Re: [time-nuts] Vintage Frequency Measurement

[Robert Atkinson via time-nuts]

Hi,Sorry if I caused confusion by calling the SCR/BC221 a wavemeter. Clearly 
it's not in the wider usage of the term, and the manual and front panel call it 
a frequency meter. However the similar British device was called a wavemeter 
"Wavemeter Class D" 
http://www.vmarsmanuals.co.uk/archive/724_Wavemeter_Class_D_No2_Working_Instructions.pdfSo
 here in the UK the 221 was often also called a wavemeter. Classic wavemeters 
were also available for example the Marconi TF975.
Robert G8RPI.

  From: Bob Camp 
 To: Discussion of precise time and frequency measurement  
 Sent: Monday, 13 February 2017, 23:46
 Subject: Re: [time-nuts] Vintage Frequency Measurement
   
Hi

With a VFO running, you have a heterodyne frequency meter. That is (at least to 
me)
a very different device than an absorption wave meter. I know way to put power 
into
a BC-221 and use it as an absorption device. 

I’m not in any way saying that the LM or the 221 are less useful. They are 
still to this day
great little boxes. The just aren’t (by my understanding) wave meters. That 
term describes
a different device that works a different way. 

Bob

> On Feb 13, 2017, at 5:52 PM, John Miles  wrote:
> 

   
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Re: [time-nuts] Vintage Frequency Measurement

[Robert Atkinson via time-nuts]

In a word,Wavemeters. Classic US onwas the BC221 with built in 100kHz crystal 
calibrator
http://radionerds.com/index.php/BC-221
British was the "Class D"http://www.royalsignals.org.uk/photos/classDno1.htm

For UHF and Microwave it was Lecher lines or cavity wavemeters.
Robert G8RPI.


  From: Scott Stobbe 
 To: Discussion of precise time and frequency measurement  
 Sent: Sunday, 12 February 2017, 6:08
 Subject: [time-nuts] Vintage Frequency Measurement
   
I was inspired recently coming across a Lampkin 105 frequency meter, as to
how  frequency measurement was done before counters.

Certainly zero-beating a dial calibrated oscillator, would be one approach.

Is there a standout methodology or instrument predating counters?
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Re: [time-nuts] purpose of time of day display units

[Robert Atkinson via time-nuts]

One must remember the original use of these displays was displaying IRIG time 
either distributed from a master clock, locally generated or from a recording 
(tape) They long predate GPS. There are more sophisticated units that include 
controls for the tape recorder so you could auto search to a certain time. 
Multiple displays could be used for locally generated time, time received from 
a remote site by fixed line or radio and time from data or video recorders.I 
have a number of them and one sits above my GPStar as the LCD on the GPStar is 
hard to read from across the workshop and it lets me have time available while 
showing timing or satellite  status on the GPS. Just picked up 3 more (RAPCO 
104 anyone have a manual for these) at the weekend.
Robert G8RPI.

  From: Bob Bownes 
 To: Discussion of precise time and frequency measurement  
 Sent: Sunday, 22 January 2017, 18:33
 Subject: Re: [time-nuts] purpose of time of day display units
   

#5) Everyone likes blinkenlights. 



> On Jan 22, 2017, at 08:55, jimlux  wrote:
> 
>> On 1/21/17 10:31 PM, Ruslan Nabioullin wrote:
>> Hi, looking at pictures of various time metrology equipment setups for
>> best practices and inspiration, I have commonly seen time of day display
>> unit(s) installed in racks containing processing or time transfer
>> equipment, e.g.,
>> http://www.xyht.com/wp-content/uploads/2015/05/Powers_Master_Clock.jpg.
>> All that these units do is merely display the time of day and sometimes
>> the date, typically by means of seven segment LED displays, of the time
>> code inputted to them (typically IRIG-B, I'm guessing).
> 
> There's a few reasons I can think of:
> 1) the display is also a distribution amplifier of some sort - one time 
> source going into rack, distributed to things in the rack (or the next rack)
> 
> 2) as phk commented, it lets you know that your time code isn't broken (i.e. 
> someone got in behind the rack and disconnected the wrong cable)
> 
> 3) It's a crude visual check - your eye/brain is pretty good at catching a 
> change in the pattern of blinky lights.  IN this situation, you'd expect all 
> the displays to change simultaneously.
> 
> 4) the equipment configuration "just growed" from a collection of smaller 
> ones, each with its own display.
> 
> We put displays like this in all of our ground support equipment (GSE) racks 
> when doing spacecraft or subsystem tests, mostly for reason #2 and #4.
> 
> You might have a GSE rack or two in the lab when you're building up the 
> subsystem.  Someone else's subsystem has their rack, also with a timecode 
> display.  When you bring the two subsystems together for integration, you 
> bring the racks with them, and it's not worth it to reconfigure.
> 
> 
> 
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Re: [time-nuts] Temperature (environmental) sensors

[Robert Atkinson via time-nuts]

I've used the Dallas (now Maxim) Thermochron iButtons in several applications. 
Looks like a thick coin with battery, ram and RTC built in. Even used dozens of 
them map temperature distribution in a aircraft fuel tank. Also available as a 
1-wire device. For precision I've used Pico Technology PT105 4 channel PRD 
interfaces.
Robert G8RPI.


  From: jimlux 
 To: time-nuts@febo.com 
 Sent: Tuesday, 3 January 2017, 15:22
 Subject: Re: [time-nuts] Temperature (environmental) sensors
   
On 1/3/17 7:08 AM, Tom Van Baak wrote:
> I have some high-end temperature and pressure instruments. But for casual use 
> in my home and mobile timing lab I use Sparkfun Weather Stations. The old URL 
> is:
>
>    https://www.sparkfun.com/products/retired/10586
>

Replaced by
https://www.sparkfun.com/products/12081
which doesn't have the USB.

By the time you add a board with a processor, you're in the $50 range..

I use these at work:

https://www.lascarelectronics.com/easylog-data-logger-el-usb-rt/
Well, actually I use the EL-USB-2-LCD.. which logs to internal memory 
and can't log/unload data at the same time and which requires a windows 
program.

That said, they work well, come with a traceable cal certificate, etc. 
I don't know that they do 0.1 degree (the data sheet says 0.5C, and I 
think that's the logging accuracy), and, well, humidity sensors are of 
dubious accuracy away from the middle of the range

https://www.lascarelectronics.com/easylog-data-logger-el-usb-2-lcd/






> It's USB, talk-only, one reading a second, temperature, pressure, humidity -- 
> about as simple as you can get. Perfect for data logging along with frequency 
> standards, GPS, counters and such.
>
> But they don't make 'em anymore. My question is what similar well-engineered, 
> talk-only, serial or USB, temperature-pressure-humidity sensors have you run 
> across and could recommend? Not to be picky bit no cheapo 1C or 0.5C sensors; 
> 0.1C or better is ok.
>
> I know it's "easy" to throw one together with an Arduino, but I'm looking for 
> something pre-packaged, something that reliably works, out-of-the-box. I have 
> backup plans but hope someone on the list knows some products they have used 
> and would recommend.
>
> We could extend the discussion to voltage and power monitors too. Or some 
> kind of universal sensor TAPR project. But for now, let's just keep it to 
> simple air / environmental sensing.
>
> Thanks,
> /tvb
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Re: [time-nuts] Is this ocxo salvageable?

[Robert Atkinson]

One other tip. If the can and base are tight fitting you can file through the 
corners of the can at 45 degrees to the sides. This breaks the stiffness of the 
can and allows the sides to be folded out slightly. Straighten them before 
re-assembly. You can build up the corners with solder to restore the original 
profile.

Robert G8RPI.





 From: paul swed paulsw...@gmail.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Wednesday, 9 April 2014, 14:04
Subject: Re: [time-nuts] Is this ocxo salvageable?
 

Totally agree with the comments here. Lot of heat and I slip an exact o
knife in to gently separate the can and base and also to gently lift the
base out.
Remember solder follows the heat so if you can tip the can apply the heat
below and the solder will tend to drip out.
The great news is since the oscillator is bad nothing to loose by trying to
get in.
Regards
Paul.
WB8TSL


On Wed, Apr 9, 2014 at 8:01 AM, J. L. Trantham jlt...@att.net wrote:

 Two other suggestions to open the can.

 If you don't have a good 'suction' de-soldering station, you can try to
 'wedge' some de-soldering braid in the seam to absorb the solder then
 proceed as Tom suggests.

 Also, if there is a way to 'grab' the can or the base, such as placing it
 in
 a vise, you can use a propane torch to heat the seam rapidly while pulling
 on the other end with a large pair of pliers.  That's how I have opened HV
 power supplies on 5061 CS Beam Standards.  They are not SMT but have a
 layer
 of thick paper wrapped around the assembly between the can and the assembly
 and were unharmed in the process.

 Good luck.

 Joe

 -Original Message-
 From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
 Behalf Of Tom Miller
 Sent: Wednesday, April 09, 2014 2:33 AM
 To: Discussion of precise time and frequency measurement
 Subject: Re: [time-nuts] Is this ocxo salvageable?

 I would agree with David. Or there is a SMT resistor or cap that is broken.

 As to opening the can, do you have a vacuum desoldering station? I usually
 use a good iron the heat the seam and at the same time suck out as much
 solder as possible. Then use a small flat blade screwdriver to pry apart
 the
 seam. You just want the seam to fail as you work it all the way around. The
 main point is to get as much of the solder out as possible.

 Take some pictures so we can see how it goes.

 Good luck,
 Tom

 - Original Message -
 From: David McQuate mcqu...@sonic.net
 To: time-nuts@febo.com
 Sent: Wednesday, April 09, 2014 2:58 AM
 Subject: Re: [time-nuts] Is this ocxo salvageable?


  The output looks differentiated, as would happen if the wire connecting
  the internal circuit to the output pin became open, leaving only a very
  small capacitance to couple the square wave out.
 
  Dave
 
  On 4/8/2014 11:46 PM, Chris Albertson wrote:
  My Bliley square wave 10MHz OCXO was working just fine for close to 30
  hours until a few hours ago.  Now it puts out a rather noisy waveform
  about
  one volt peak to peak.
 
  Two questions:
  (1) Are these things repairable, the metal can is soldered.
 
  (2) As you can see in the attached oscilloscope photo the OCXO still
 puts
  out a strong 10MHZ component.  What is the best way to filter this and
  recover a good 10MHZ square wave?
 
  In the linked photo, both channels are set to 1 volt per division.  The
  large sine wave is from a Trimble Thunderbolt and the smaller wave is
  from
  the failed ocxo  The EFC is left open (disconnected) and a you can see
  the
  frequency is spot on 10MHz.
 
  https://www.dropbox.com/s/0gy3yobd4myi4vp/waveform.jpg
 
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Re: [time-nuts] Sound impact Was FEI-5660 Rubidium Oscillator

[Robert Atkinson]

Back in 1997 when working on a car project I saw several failures of AD595 
Thermocouple converter chips due to sound. In all cases the bond wire to pin 8 
of the CERDIP package failed, presumably due to resonance (I took the top of 
the chips to check) A blob of non acid cure RTV silicone rubber on the chip 
seemed to cure it. The box with the AD595s was mounted in the rear of the car 
between the exhaust plumes of two 20,000lb thrust re-heated jet engines so the 
sound level was quite high :-) The box is in the open wheel compartment seen 
here http://upload.wikimedia.org/wikipedia/commons/4/41/ThrustSSC_back.jpg
 
 Robert G8RPI. 


 From: Bob Camp li...@rtty.us
To: Tom Van Baak t...@leapsecond.com; Discussion of precise time and 
frequency measurement time-nuts@febo.com 
Sent: Friday, 28 March 2014, 11:33
Subject: Re: [time-nuts] FEI-5660 Rubidium Oscillator
  

Hi

Crystals are susceptible to vibration. That’s pretty well documented. They have 
resonances in the mount structure. They have a 2G tip sensitivity. 

Audio when it “impacts” an oscillator induces vibration. If your noise source 
is a rocket engine, then the vibration is “non trivial”. You do indeed see 
phase noise on the oscillator from audio …

Bob

On Mar 27, 2014, at 11:42 PM, Tom Van Baak t...@leapsecond.com wrote:

 More seriously, I'm assuming you're advocating rock for the thermal mass 
 and/or mechanical.  What about a 100 pound box of sand?
 
 Mechanical. I figured a OCXO might be susceptible to microphonics, especially 
 in a recording studio. But if it's down to the level of 1 lsb of the digital 
 sampling, then no worries.
 
 Has anyone on the list ever measured this effect, even on a cheap crystal?
 
 /tvb
 
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Re: [time-nuts] Using GPS to Fine Tune a Rubidium Frequency Standard.

[Robert Atkinson]

Hi Anders,
You can buy the 2013 QST CD-ROM from ARRL which includes QEX. I'm in the UK 
and have this CD, international delivery was no problem. Cost was $25, see 
http://www.arrl.org/shop/ARRL-Periodicals-DVD-2013/  The disk is well worth the 
cost.
I've not built the project but have looked at the article. It references the 
Shera design and is basically a Trimble Resoluton T to LPRO101 GPSDO. It 
divides the 10MHz to 100kHz before comparison. I'm not qualified to comment on 
how good the design is, but you can contact me off-list if you want more 
details.


Robert G8RPI.




 From: Anders Time anderst...@gmail.com
To: time-nuts@febo.com 
Sent: Friday, 21 March 2014, 13:20
Subject: [time-nuts] Using GPS to Fine Tune a Rubidium Frequency Standard.
 

Does anyone have a copy of the QEX 2013 november article(Bill Kaune) Using
GPS to Fine Tune a Rubidium Frequency Standard?

I´m really interested in this subject, but I can´t find this magazine in
Sweden. I have contacted QEX, but it is very difficult to buy back-issues.

Have any one built this frequency standard and can tell me more about the
project?
You can access the source code for the project here:
http://www.arrl.org/files/file/QEX%20Binaries/2013/November_13/11x13_Kaune_PIC_Code.zip

/Anders
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Re: [time-nuts] Finding a spare part for HP5370B

[Robert Atkinson]

It's part No 05370-20206, no longer available from Agilent. I don't think you 
will find one easily. Best bet is to buy some plastic and make one. The 
proper plastic filter material is polarised to increase contrast but thin red 
acrylic sheet will do OK. masking the annciators may be tricky. Try a black on 
clear label maker. A professional one should be able to do the required 
mirrored (you will be sticking it to the inside of the window) and negative 
(clear on black) label.
HTH,
Robert G8RPI.
 


 From: Pascual Arbona Lopez p.arb...@securimar.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Saturday, 8 March 2014, 7:21
Subject: [time-nuts] Finding a spare part for HP5370B
  

Hello!

I have been given an HP5370B; I have checked  it and it seems to work fine, but 
unfortunately its missing the red plastic in the display window.
If anyone has one of these equipments for spare parts, I would be very grateful 
if I can buy  this part. Please contact me off list if
you can help at p.arb...@securimar.com 
  
    Many thanks
      P. Arbona



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Re: [time-nuts] FSCM 38243 Power Distribution Module

[Robert Atkinson]

From the construction and components used it isn't UHF ;-) It appears to be 7 
two way splittters in series and the transformers look to have plenty of turns.

As you have a 10MHz source why not just try it out? You should get about 9dB 
attenuation input to output with the other ports terminated in 50R. This could 
be checked by reference to a 10dB attenuator with a 50R load, diode and 
multimeter as indication if you don't have an accurate power meter. 

Or if you ship it to me I can stick it on a VNA and give you exact specs. 

HTH
Robert G8RPI.




 From: d0ct0r t...@patoka.org
To: time-nuts@febo.com 
Sent: Sunday, 2 March 2014, 5:54
Subject: [time-nuts]  FSCM 38243 Power Distribution Module
 


Does anybody knows if FSCM 38243 8-way P/D module is suitable for 10MHZ 
frequency ? The module I have, has no other information on it except 
Serial No.: 171-0100-048. Looks like its old Minicircuits product. But I 
am not sure.  I am planing to connect 10Mhz GPSDO output to it.

-- 
WBW,

V.P.

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Re: [time-nuts] How to open solder-sealed OCXOs?

[Robert Atkinson]

Hi Graeme,
A technique I've found useful is to first remove the corners of the outer can 
by filling across them. I then rake out as much of the solder along the seams 
with the back edge of a disposable snap-off craft knife / box cutter. Finally 
wedging the sharp edge to break the joint. Removing the corners releves the 
stiffness and allows the edge of the can to be bent back in a straight line 
rather than a rough set of bumps. 
On many hermetically sealed aircraft instruments they put a tear wire at the 
bottom of the solder joint with a tail sticking out. You just grasp this and 
pull. While the joint geometry on the aircraft instrument is designed for this 
(typically with a non-metallic packing under the wire) and your OCXO isn't, it 
is a good idea to leave the case slightly flaired and lay a length of tinned 
copper wire in it before ligthly soldering over the top.  


Robert G8RPI.



 From: Graeme Zimmer gzim...@wideband.net.au
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Sunday, 2 February 2014, 8:50
Subject: Re: [time-nuts] How to open solder-sealed OCXOs?
 


 What's the best way to open an OCXO in the typical solder-sealed tinned
 steel can?

Use a high wattage iron to melt the solder at one point, prise the gap 
open with a flat screwdriver, then work along the join.

Solder is soft. so once you get it started you should be able to roll it 
open like a can of tuna.

You could use a dremmel and a cutting disk, but the vibration might kill 
the Xtal.

Alternatively, a hot air gun might work if you are quick enough not to 
cook the innards.

 Zim

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Re: [time-nuts] Trimble Thunderbolt 1pps

[Robert Atkinson]

Hi,
I looked at this a while ago. The spec only defines transmission levels, it 
does NOT specify receive thresholds. All the receiver chips I've looked at, 
ancient and modern, have only positive thresholds. Most have single supplies 
and clamp the input at 1 diode drop negative WRT common after an input current 
limiting resistor, see the MC1489 datasheet. Even the MAX style devices with 
built-in charge pumps have a Input Logic-Low Voltage range of 0.8 to 1.3V

Going negative does help with noise immunity. If you drive the TX to -9V then 
you need more than 9V of noise to loose the data.

Robert G8RPI.




 From: paul swed paulsw...@gmail.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Monday, 27 January 2014, 14:44
Subject: Re: [time-nuts] Trimble Thunderbolt 1pps
 

OK I can add something here.
Yes the spec is correct. But modern receiver chips actually can work with
single side signals. You have to look at the specs of the chip to see what
they will do.
Granted noise immunity is much lower but for most of us in the 10' run
distance its good enough. I operate this way on lots of things.

Seriously sleazy way to get +/- swings as long as the data flows somewhat
all of the time like GPS. Put the unipolar signal through a 1-10UF cap.
Smaller is better to a point.
Did I really suggest that. Will never admit it.
Regards
Paul.
WB8TSL


On Mon, Jan 27, 2014 at 9:08 AM, Attila Kinali att...@kinali.ch wrote:

 On Sun, 05 Jan 2014 13:35:43 -0800
 Hal Murray hmur...@megapathdsl.net wrote:

 
  att...@kinali.ch said:
   Also keep in mind that RS-232 relies on the voltage going negative to
 encode
   a 1. I.e. getting 0V is not enough and might only work by chance
 with some
   RS-232 receivers.
 
  I think there are 2 parts to this discussion.  What do the specs say, and
  what actually happens in the real world?
 
  I think the specs say that -3 to +3 is no mans land.  A valid signal
 must be
  over +3 or under -3.

 IIRC that's right. But i haven't had a look at the standard for a very
 long time.


  In practice, the receiver chip only has one power supply.  It would take
  extra work to make the switching threshold below ground.

 That's not correct. Standard transceiver chips (like the MAX232 family)
 have an integrated charge pump to get a negative power supply.

 I have never done exact measurements, but my experience is that going
 a bit (0.5V?) below GND and slightly more above GND is enough to get
 a proper 1/0 detection. Of course, if you rely on that you get a very
 poor noise performance.



                         Attila Kinali

 --
 The trouble with you, Shev, is you don't say anything until you've saved
 up a whole truckload of damned heavy brick arguments and then you dump
 them all out and never look at the bleeding body mangled beneath the heap
                 -- Tirin, The Dispossessed, U. Le Guin
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Re: [time-nuts] Trimble Thunderbolt 1pps

[Robert Atkinson]

Hi Javier,
Our posts crossed. However the 1489 has a positive threshold (they call it turn 
off threshold) of 0.75 to 1.25V. They can be shifted to a negative trigger 
range using the response control pin but this is just a voltage divider and 
offset voltage, you still only get hysteresis of 1.1V for the A version. 
Interestingly the dataheet you linked to says the RS232D spec has a +/-3V 
threshold (6V hysteresis). I must have missed this or read a different version. 
I've still not seen a packaged receiver that meets this specification.

Reobert G8RPI.





 From: Javier Herrero jherr...@hvsistemas.es
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Monday, 27 January 2014, 15:35
Subject: Re: [time-nuts] Trimble Thunderbolt 1pps
 

On 27.01.2014 15:08, Attila Kinali wrote:
 In practice, the receiver chip only has one power supply.  It would take
 extra work to make the switching threshold below ground.
 That's not correct. Standard transceiver chips (like the MAX232 family)
 have an integrated charge pump to get a negative power supply.

Hello,

The venerable MC1489 does not need a negative supply, and can have a 
threshold below ground, without too much complication. 
http://www.onsemi.com/pub_link/Collateral/MC1489-D.PDF (the receiver 
circuit diagram is shown)

On the other side, the MAX232 has positive thresholds in the receiver 
side http://datasheets.maximintegrated.com/en/ds/MAX220-MAX249.pdf pag. 6

Regards,

Javier


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Re: [time-nuts] Trimble Thunderbolt 1pps

[Robert Atkinson]

Hi,
I'd  already admitted my miss on that one in an earlier reply (don't know how i 
missed it but it was not a controlled copy of the spec ;-) .
That not withstanding, show me a readily available receiver chip that actually 
meets that requirement. Most equipment that I've seen that would not work with 
5V logic levels was failing to respond to the positive input level not the lack 
of a negative level. Ofteh this appeared to be caused by external circuitry, 
most likely intended for EMI/ESD/surge protection.
 


 From: Mike S mi...@flatsurface.com
To: time-nuts@febo.com 
Sent: Tuesday, 28 January 2014, 2:01
Subject: Re: [time-nuts] Trimble Thunderbolt 1pps
  

On 1/27/2014 1:33 PM, Robert Atkinson wrote:
 I looked at this a while ago. The spec only defines transmission levels, it 
 does NOT specify receive thresholds.

It certainly does...

2.1.3 For data interchange circuits, the signal shall be considered in 
the marking condition when the voltage on the interchange circuit, 
measured at the interface point, is more negative than -3 volts with 
respect to Circuit AB (Signal Common). The signal shall be considered in 
the spacing condition when the voltage is more positive than +3 volts 
with respect to Circuit AB (see 6.2). The region between +- 3 volts is 
defined as the transition region. The signal state is undefined when the 
voltage is in this transition region.

- ANSI TIA/EIA-232-F (1997)

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Re: [time-nuts] Affordable (cheap) COTS / eBay kit for TIE / 1PPS phase comparison

[Robert Atkinson]

Hi,
For a low cost startup have a look at a picPET 
 http://www.leapsecond.com/pic/picpet.htm  and TimeLab
 http://www.ke5fx.com/timelab/readme.htm 
 Less than $10 including shipping!





 From: Wojciech Owczarek wojci...@owczarek.co.uk
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Wednesday, 22 January 2014, 1:23
Subject: [time-nuts] Affordable (cheap) COTS / eBay kit for TIE / 1PPS phase
comparison
 

Hi List,

I'm a software developer turned network test engineer slowly turning
timefrequency guy (not sure if this is upwards or downwards ;-) ) with
some distant background in electronic engineering.

For the last couple of years I have been increasingly involved in various
work involving IEEE 1588 and finally I started fitting out a small home lab
setup. I never really needed lab kit at home before and my work lab is
primary to do with Ethernet and IP (and timing, but outside my price
ranges), so I was wondering if you could point me in the right direction:

I'm looking for some reasonably inexpensive solution to allow me a) to do
TIE measurements of 1PPS signals against a reference and b) do phase
comparisons of different 1PPS signals - so something with REF and at least
two inputs.

I have an OCXO GPS reference (upgradable to Rb) with 1PPS, 5MHz and 10MHz
outputs which is stable enough for my needs so that part (perhaps most
important) is sorted. In terms of requirements, granularity wise, well, as
good as achievable - I'm used to 10 ns and 5 ns granularity with TIE that I
get from work kit. 50 ns or better would be perfect.

I must add that ideally I would like to avoid having to design or build the
kit myself - I would love a project, but I have time to spare to complete
one.

Any pointers much appreciated.

Best regards
Wojciech

-- 
-

Wojciech Owczarek
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Re: [time-nuts] Spectrum Analyzer Suggestions

[Robert Atkinson]

Hi Mark,
late response, but I've been looking at the 3582A. Using a mixer for PN at 
higher frequencies is OK, see  
http://www.hpmemory.org/technics/bench/3048/pn_measrmt_single.htm 
Pretty good for comparing a number of oscillators. You can use a doubler 
(HP10115A  http://www.leapsecond.com/pages/20mhz/ ) to compare a 5MHz and 
10MHz OCXO. 
The 3582A cost over $14,000 in 1990.

Robert G8RPI.






 From: Mark C. Stephens ma...@non-stop.com.au
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Sunday, 14 July 2013, 18:00
Subject: Re: [time-nuts] Spectrum Analyzer Suggestions
 

2 Seconds After I sent that, I thought, what am I saying, what can we measure 
from 0.02-25Khz besides audio or seismic events?!
The 3582A phase spectrum function is interesting.
I suppose one could employ some sort of LO/mixer to get it down to 25Khz but 
would mess the phase up anyway.

The 3582A is 25Kg, the 3585A is 40Kg.

Actually, looking at the spec sheet the 3585A is 20Hz-40Mhz, not 10Hz.
3585A Residual phase noise (typical at 40 MHz, -10 dBm input), 5 KHz offset: 
-112 dBc/Hz.  100 KHz offset: -120 dBc/Hz.
Which is about what I get in PN.exe.

3568B is specified -107dBc @ 30kHz offset, I am getting way lower than that, 
seems noise floor for me is ~-170 in PN.exe.
But I don't know how accurate it is way down there.


-marki

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf 
Of Mark C. Stephens
Sent: Monday, 15 July 2013 2:35 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Spectrum Analyzer Suggestions

I just wish John Miles could get it into the Phase noise list of sources..

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf 
Of dlewis6...@austin.rr.com
Sent: Monday, 15 July 2013 2:12 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Spectrum Analyzer Suggestions

Consider the HP 3582 for the 'lower-end', ...it is a very nice SA (using FFT). 
Slow, tho. It tops out at 25KHz, but has a long list attributes.  ...some being 
lightweight and modestly 'affordable.'

-Don Lewis
Austin, TX  (Hyde Park)









 K3wry k3...@aol.com wrote: 
 Take a look at the RIGOL analyzer.   You can get this new one for about the 
 same money

Dr Joe PALSA
804-350-2665
Sent from my iPhone.


On Jul 14, 2013, at 1:18 AM, Mark C. Stephens ma...@non-stop.com.au wrote:

Perry I have a 3585A too, The weight isn't so bad once you get used to it. :) 
Mines on a rack shelf that I can slide it out onto the workbench for 
maintenance.

Performance wise, they are fantastic for phase noise measurement using John 
Miles's Phase noise software.
Although a little slow, It is pretty nice to see what's going on down at 10 Hz.

I really can't find a replacement for my 3585A, other than the B model.

Also the boards come up cheap on eBay if you need parts.
I have almost a complete set of spare boards I bought for 10 bucks each.

So all in all, you got yourself a good Analyser, cheap to maintain and good 
specs.

Run it through the performance tests as per the manual, this SA will be a 
pleasant surprise for you :)


-marki


-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf 
Of Perry Sandeen
Sent: Sunday, 14 July 2013 1:10 PM
To: time-nuts@febo.com
Subject: [time-nuts] Spectrum Analyzer Suggestions



List,

I just purchased a HP 3585 spec analyzer on E bay for a reasonable price.  I 
wanted this instead of the 181 series as the range was more to what I’d be 
using and it was of a newer vintage.  The 3585a goes from
10 Hz to 40 MHz which is a most useful range for my purposes. so far, so good.

The problem is I didn’t know the beast weighed a svelte
88 pounds! Double Hernia time!

What I’d appreciate advice for a used spec analyzer in the $1,000 range that is 
at least much lighter.  A smaller size would also be a benefit.  I probably 
would never use it above 100 MHz. A slightly smaller screen would be OK.

Suggestions appreciated.

Regards,

Perrier
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Re: [time-nuts] HP 5328A fan - suspected issue

[Robert Atkinson]

Hi Brett,
In the 5328A the unregulated 25V DC supply and OCXO run whenever the unit is 
connected to power. The on/off switch controls the main circuits power supply. 
The triac (Q12) and opto-coupler (U6) turn on the fan when the 3.5V DC supply 
is present (its only active wthe the unit switched on). The oprimal solution 
would be to use a 24V DC fan running from the raw DC (junction of F1  R1) with 
it's negative lead switched to ground by a NPN transistor whose base is 
connected to the 3.5V DC (with a series resistor of course. I'd remove Q12 and 
U6 and all the associated 115V AC wiring. you can then pick up the 3.5V from 
the pad where U6 LED anode was connected). If you can only find a 12V fan just 
put a 12V zener in series with the fan (anode to fan cathode to F1). To slow 
the fan and reduce noise use a higher voltage zener.
Also consider one of the variable speed temeperature controlled fans with 
remote sensor. Put the sensor out of the direct airflow.

HTH,
Robert G8RPI.






 From: Brett Owen Rees bre...@gmail.com
To: time-nuts@febo.com 
Sent: Friday, 17 January 2014, 23:03
Subject: [time-nuts] HP 5328A fan - suspected issue
 

Hi all,

This is my first post to this list. I recently acquired three HP 5328A
counters and have been using one in my shack. They all seem to have fan
issues, with the fans not running in two of them and in the third unit a
resistor near the fan starts to smoke if I turn it on. All of the fans look
identical, being 110V AC units.

So, I have some questions:
- should the fan run all of the time or is it on a thermostat
- does the smoking resistor mean that the fan is seized
- can I replace it with a 5V/12V computer fan. If so, can I safely tap DC
off the power supply and will the fan introduce any electrical noise? I am
240V here so sourcing a fan 110V fan locally may be difficult

The counter I have running seems ok without the fan running. It is the pick
of the bunch with the OCXO, 525MHz and DVM option. Being the best
oscillator I have currently, I have checked it against WWV and it seems ok.
I also used it as an alignment  reference for a funcube dongle receiver
(with tcxo) and am receiving WSPR spots on frequency, so I think it is
good. I am slowly getting the time-nuts bug and am building a GPSDO with a
Morion MV89A ocxo ...

Many Thanks es 73
Brett VK6EZ


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Re: [time-nuts] R: HP 5328A fan - suspected issue

[Robert Atkinson]

Hi Antonio,
It should run when the ON/OFF switch is ON but not if it's OFF. If the fan runs 
whenever the power is connected there is a fault, probably a shorted TRIAC. 
Interestingly on the 5328B they added an RC snubber across the TRIAC which may 
indicate they had problems with the A model. Alternatively somone may have 
modified it. The military AN/USM-459 manual still shows the fan as being 
controlled. The original fan was 35 to 45 CFM (depends on the source of data) 
so a small 24V DC fan drawing around 100mA should work fine without excessively 
loading the supply. Any one know a makers part No. or frame size for the 
original fan? HP don't give these details. I'm assuming it's a 80mm unit but 
may be wrong as the 5328A is only 89mm high.

Robert G8RPI.



 From: iov...@inwind.it iov...@inwind.it
To: time-nuts@febo.com 
Sent: Saturday, 18 January 2014, 12:57
Subject: [time-nuts] R:  HP 5328A fan - suspected issue
 

I had five 5328A, three military and two normal, and still own three. The fan 
runs whenever the unit is turned on and never stops. In the military version 
the fan is much noisy.
Antonio I8IOV


Da: bre...@gmail.com
Data: 18/01/2014 0.03
A: time-nuts@febo.com
Ogg: [time-nuts] HP 5328A fan - suspected issue

Hi all,

This is my first post to this list. I recently acquired three HP 5328A
counters and have been using one in my shack. They all seem to have fan
issues, with the fans not running in two of them and in the third unit a
resistor near the fan starts to smoke if I turn it on. All of the fans look
identical, being 110V AC units.

So, I have some questions:
- should the fan run all of the time or is it on a thermostat
- does the smoking resistor mean that the fan is seized
- can I replace it with a 5V/12V computer fan. If so, can I safely tap DC
off the power supply and will the fan introduce any electrical noise? I am
240V here so sourcing a fan 110V fan locally may be difficult

The counter I have running seems ok without the fan running. It is the pick
of the bunch with the OCXO, 525MHz and DVM option. Being the best
oscillator I have currently, I have checked it against WWV and it seems ok.
I also used it as an alignment  reference for a funcube dongle receiver
(with tcxo) and am receiving WSPR spots on frequency, so I think it is
good. I am slowly getting the time-nuts bug and am building a GPSDO with a
Morion MV89A ocxo ...

Many Thanks es 73
Brett VK6EZ


-- 
Mobile: +61 468 512095
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Re: [time-nuts] also contins lanolin

[Robert Atkinson]

Hmm,
Input dynamic range of 1.2V Pk-Pk and 125Msps, like that's going to replace ALL 
my test equipment. It's also not clear if they are in Newport VA or Slovenia, 
but the plug on the mains adaptor says Slovenia. I'm stunned that 826 people 
would consider spending hundreds of dollars on this toy. It doesn't even have a 
case to protect it. 


Robert G8RPI.




 From: Don Latham d...@montana.com
To: time nuts time-nuts@febo.com 
Sent: Tuesday, 14 January 2014, 17:50
Subject: [time-nuts] also contins lanolin
 

Vey Interesting!
http://www.kickstarter.com/projects/652945597/red-pitaya-open-instruments-for-everyone
production Real Soon Now.
Don


-- 
The power of accurate observation is commonly called cynicism by those
who have not got it.
-George Bernard Shaw


Dr. Don Latham AJ7LL
Six Mile Systems LLC
17850 Six Mile Road
POB 134
Huson, MT, 59846
VOX 406-626-4304
Skype: buffler2
www.lightningforensics.com
www.sixmilesystems.com


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Re: [time-nuts] WAAS.....

[Robert Atkinson]

Hi,
This is a known problem. It's leakage form the local oscillator (LO) of the 
Ky197. The KYa97 has a 10.7 MHz IF and high side local oscillator. So the LO is 
119.9 + 10.7 = 130.6MHz. 12th harmonic is in the GPS bandwith. 
Cure is a notch filer on the KY197 antenna connector. examples are a TED 
4-70-54 
http://www.edmo.com/index.php?module=productsfunc=displayprod_id=18006 or 
Telegartner J01006A0017 or make your own with a BNC T and a bit of rigid coax 
(Experimental or permit Acft only :-).
 
Other radios including VHF Nav have similar issues. 
 
Robert G8RPI
(CEng MRAeS)


 From: J. L. Trantham jlt...@att.net
To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com 
Sent: Friday, 10 January 2014, 1:53
Subject: Re: [time-nuts] WAAS.
  

I have had loss of GPS position on a 'hand-held' unit (Garmin GPSMAP 396)
when flying into PNS.  When I switch to tower frequency (119.9 MHz) the unit
loses its position.  I think it is related to some 'spur' related to the #1
Nav/Com (King KY197) being tuned to that frequency.  If I replace the unit's
GPS antenna with the 'remote' antenna, secured to the windshield, all the
problems go away.

I think it is a 'spur' of the appropriate magnitude when the 'portable'
antenna is still installed.

Joe

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Brian Lloyd
Sent: Thursday, January 09, 2014 8:47 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] WAAS.

On 1/9/14 12:20 AM, Joe Leikhim wrote:

 GPS jamming, intentional or not is pretty serious, and the FCC takes 
 this seriously, but unless you have some pretty hard evidence they may 
 not find it.
In my case my most interesting outage was when I lost all GPS while over the
Atlantic ocean between Haiti and the island of Great Inagua in the Bahamas.
It is a bit difficult to stop and look around while flying at 8,500'. I took
it for a general GPS outage but now I suspect jamming.

When I was living on my boat in the Virgin Islands (I built a WiFi-based
WISP for marinas and anchorages in the USVI) the US Customs interdiction
boat was only about 4 slips away from me. I often talked with the agents
either going out or coming back from a run. (You do NOT want to screw with
these guys! They are armed to the teeth!) I now realize that they would jam
GPS so that the druggies couldn't get their drops right. (They also admitted
that, most of the time, they couldn't find the drug runners' boats anyway
and figured they got less than 5% of what they were after. So much for the
War on Drugs.)

The US Coast Guard had (has?) a base on Great Inagua. They run a fleet of
helicopters out of there for __ (redacted - read between the
lines). I got a kick how, when they were coming and going, they would
announce their movements to other aircraft using a civil ID rather than
their military flight ID. At this point I suspect I may have been shadowed
and my GPS jammed. Thank god my airplane still had an LF/MF automatic
direction finder (ADF) aboard. I was able to fall back to navigating using
the non-directional LF beacon on Great Inagua. After refueling at Great
Inagua I continued on sans GPS for nearly 100mi when
POOF GPS suddenly came back on.

I wonder what the FCC does if it discovers it is another governmental agency
that is doing the jamming? ;-)

I must admit, I like the idea of multi-system sensors that will track GPS,
GLONASS, and (hopefully) Galileo and the Chinese satellite-based navigation
system that is going up. For that matter, is anyone running one of the new
multi-system receivers? I notice that Garmin is selling them as a matter of
course now. The prevalence of jamming might be the reason why.

-- 

Brian Lloyd, WB6RQN/J79BPL
706 Flightline Drive
Spring Branch, TX 78070 USA
br...@lloyd.com
+1.916.877.5067


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Re: [time-nuts] Update on my previous note regarding NBS television timing reference experiment

[Robert Atkinson]

Here in the UK we had a version of this for nearly 40 years. It was called 
Ceefax or TeleText. Chunky graphics with the time, weather and lots of other 
information. it was also used for closed captioning. see  
http://en.wikipedia.org/wiki/Teletext  It was the best generally available 
time source for years. 
 
Robert G8RPI.
 


 From: Gregory Muir engineer...@mt.net
To: time-nuts@febo.com 
Sent: Thursday, 2 January 2014, 23:31
Subject: [time-nuts] Update on my previous note regarding NBS television
timing reference experiment
  

I did a little digging and managed to find a paper on the original television 
time experiment which was authored by David Howe of NBS, now head of the Time 
and Frequency Metrology Group at NIST.  It can be found at 
http://www.google.com/url?sa=trct=jq=esrc=sfrm=1source=webcd=2cad=rjaved=0CDYQFjABurl=http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F3092613_Nationwide_Precise_Time_and_Frequency_Distribution_Utilizing_an_Active_Code_within_Network_Television_Broadcasts%2Ffile%2F9fcfd5089a1d534c56.pdfei=Ze_FUsrXJ-LsyQGY0oHYCwusg=AFQjCNGw2wK-8_RYN98R_72AlRLcm2BAUAbvm=bv.58187178,d.aWc(Google
 cached - whew!).

I stand corrected in my assumption that the timing signal was not related to 
the VITS interval in the video signal.  They actually were inserting the signal 
on line 1.  At the time Mr. Howe was involved in the development of the 
hardware that was deployed in the field for the experiment.   He stated that 
the received code provided unambiguous time to 12 hours, with a resolution of 1 
nanosecond and long-term stability of 10 nanoseconds for 10-second averaging.

It's rather odd as to why I can't remember the sordid details off the top of my 
head regarding a project that took place 42 years ago

Greg
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Re: [time-nuts] Motorola GPS antenna type GCNT20A3A

[Robert Atkinson]

I know Goldmine would not sell duff stuff knowingly, but the Engineering 
Sample label worries me a little. Often this is indicates a non-functioning 
item for display or trial fit purposes. Then again it maybe not. I can't find 
out as they don't ship outside the USA.
Robert G8RPI.



 From: Russ Ramirez russ.rami...@gmail.com
To: time-nuts@febo.com 
Sent: Wednesday, 11 December 2013, 23:57
Subject: [time-nuts] Motorola GPS antenna type GCNT20A3A
 

FYI, in case anyone should be interested. $20

http://www.goldmine-elec-products.com/prodinfo.asp?number=G19738

Russ
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Re: [time-nuts] MS3106R10SL-4S connector question

[Robert Atkinson]

Hi,
John is correct. The plastic pin is used when a contact position is not wired. 
You put the unwired pin in first and then insert the plastic pin behind it, 
thick end first. It replaces the wire to seal that individual hole and also 
maintain correct seal pressure on the other wires. Blue for #16 pins, Red for 
#20. Not required if you don't need a full environmental seal. 

Robert G8RPI. CEng, MRAeS, EASA licenced avionics engineer. (i.e. this is a 
definitive answer, I can certify that one of these is correctly installed on an 
aircraft :-)





 From: J. Forster j...@quikus.com
To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency 
measurement time-nuts@febo.com 
Sent: Tuesday, 10 December 2013, 2:58
Subject: Re: [time-nuts] MS3106R10SL-4S connector question
 

It's what I said. A blanking pin for the hole in the rubber seal, except
that it's only for the seal, not the whole connector.

-John




 Take a look at ebay auction 261315795465.  It's a mil-spec connector and I
 don't see any way for the connector pins to come out.  It looks like it's
 probably pressure tight.  You can see the blue plastic pin in the third
 picture.  It's almost like it has something to do with the rubber strain
 relief/enviro shield, but I dunno what.

 Bob





 From: J. Forster j...@quikus.com
To: Bob Stewart b...@evoria.net; Discussion of precise time and
 frequency measurement time-nuts@febo.com
Sent: Monday, December 9, 2013 8:33 PM
Subject: Re: [time-nuts] MS3106R10SL-4S connector question


If the contacts are loose and individually extractable/insertable, the
 pin
is probably a dummy pin to substitute for the more expensive brass/gold
pins. This is so the rubber does not distorted over time.

-John


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Re: [time-nuts] MS3106R10SL-4S connector question

[Robert Atkinson]

Hi Bob,
Not quite. You push the thick end of the plastic plug (technically a wire hole 
filler which says it all) into the rubber seal from the wire (back) side of 
the connector. You should of course have put an uncrimped pin in the positon 
first. 
There is some guidance here 
http://www.pavetechnologyco.com/faq/pdf/csg130-132.pdf
Note that this is a MIL-DTL-5015 series connector and is also available with 
fixed solder pins (class A and C) rather than the removeable pis of the class R 
if to are bored see 
http://www.assistdocs.com/search/document_details.cfm?ident_number=5201StartRow=1PaginatorPageNumber=1doc_id=5015status_all=ONsearch_method=BASIC
and click on the revision H pdf icon.

HTH,
Robert G8RPI





 From: Bob Stewart b...@evoria.net
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Tuesday, 10 December 2013, 18:38
Subject: Re: [time-nuts] MS3106R10SL-4S connector question
 

Thanks Robert.  So, am I right in thinking that you insert the small end from 
the connector side of the rubber grommet and pull it through until the thick 
part just touches the narrowed place in the grommet?  They have it sized to 
imply that.  Are there any assembly documents on the net that lay it out in a 
straightforward manner?  I couldn't find anything related to the plastic pin.  
Note that this is for future info.  I've assembled my connector with 2 wires 
and given it my blessing.  =)

Bob






 From: Robert Atkinson robert8...@yahoo.co.uk
To: j...@quikus.com j...@quikus.com; Discussion of precise time and 
frequency measurement time-nuts@febo.com 
Sent: Tuesday, December 10, 2013 12:27 PM
Subject: Re: [time-nuts] MS3106R10SL-4S connector question
 

Hi,
John is correct. The plastic pin is used when a contact position is not wired. 
You put the unwired pin in first and then insert the plastic pin behind it, 
thick end first. It replaces the wire to seal that individual hole and also 
maintain correct seal pressure on the other wires. Blue for #16 pins, Red for 
#20. Not required if you don't need a full environmental seal. 

Robert G8RPI. CEng, MRAeS, EASA licenced avionics engineer. (i.e. this is a 
definitive answer, I can certify that one of these is correctly installed on 
an aircraft :-)


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[time-nuts] Man killed in quartz crystal accident

[Robert Atkinson]

The US Chemical Safety Board have released their report into the 2009 accident 
at NDK's synthetic crystal growing facility in Belvidere IL  
http://www.csb.gov/assets/1/19/CSB_CaseStudy_NDK_1107_500PM.pdf 
It also describes the process.

Basically a 50ft autoclave failed, killing a member of the public at a rest 
stop 650ft away. Looks like management decisions, probably based on cost, 
overriding engineering advice even following an earlier minor incident. The 
letters from a consulting engineer in the annex make interesting reading. It 
illustrates the importance of those professional engineers amongst us notifying 
and recording any safety issues we discover. The facility is still shut down 
and the insurance company won't settle as NDK were told of possible issues.

Robert G8RPI.
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Re: [time-nuts] Crude Survey Technique

[Robert Atkinson]

Hi Jim,
I disagree, the Medium Landing Compass IS accurate to better than 30 minutes 
(0.5deg). This is also the smallest graduation so it can be read to better than 
15 minutes. The calibration chart is given to 10 minutes every 15 degrees. It 
does of course indicate the orientation of the local magnetic field. To ensure 
there is no local distortions you need to do a site survey. This can be 
acheived by comparing bearings to a distant object along a baseline or taking 
reciprical bearings. CAA CAP562 part 8 leaflet 1 
http://www.helitavia.com/docs/CAP562_2007_08.pdf  
has lots of good info.

(full version here http://www.caa.co.uk/docs/33/CAP562RFS.pdf  large file over 
10MB)

Robert G8RPI (CEng, licenced aircraft engineer for 30 years, I've done many 
aircraft swings)  




 From: Jim Lux jim...@earthlink.net
To: time-nuts@febo.com 
Sent: Friday, 22 November 2013, 14:25
Subject: Re: [time-nuts] Crude Survey Technique
 

On 11/21/13 11:32 PM, Robert Atkinson wrote:
 I'd also go for a compass if you want magnetic north, but then I have a good 
 one, a medium landing compass. Mine dates from WWII but they are still made 
 http://www.sirs.co.uk/ground/landing_compasses/patt2/landing_resource
 These are used to align the standbay and remote reading compasses on 
 aircraft. Good to half a degree. If you need better ther is the Watts Datum 
 Compass.

 Robert G8RPI.

That compass is *precise* to 1/2 degree, but not *accurate* to 1/2 
degree. It comes with a calibration card, and is presumably used in a 
place with a uniform field (e.g. for calibrating an aircraft compass, 
which is done in an open area with no known magnetic anomalies).  If 
you're in a different environment, the card values may be incorrect.

It is essentially as comparison standard.  You put it next to the 
aircraft and move both in a systematic pattern and you use it to 
calibrate out the variations in the plane's internal compass.

However you're going to be subject to the local magnetic field anomalies 
(and they're surprisingly large).

http://minerals.usgs.gov/news/newsletter/v1n2/3aeromag.html

On the 1km scale maps in the USGS reports, you can see magnetic 
anomalies of 500 nT.  Earth's field is about 30-60 microTesla, so these 
anomalies are in the one part in 100 kind of range.  It is true that 
the gradient is fairly small: It is unlikely you have an anomaly of 500 
nT and your neighbor has -200 nT. But it's obvious that the magnetic 
variation (angle between true and indicated magnetic north) isn't the 
nice smooth surface implied by the map of variation you get with the 
compass.

http://dspace.sunyconnect.suny.edu/bitstream/handle/1951/47859/Winslow_MS.pdf;jsessionid=7D7A116045A54816C9DCF963AF3D2580?sequence=1

is a short paper that talks about gradients in a small scale anomaly of 
0.22 nT/meter  (and I get the impression that that is big).

There's also other locally produced magnetic fields you'd have to worry 
about.

I gave an EM class a problem to figure out if you could tell whether 
you could use a hand compass to tell if the Pacific Intertie 1MV HVDC 
link (3000 A) was operating bipolar or unipolar. (at 50 meters, the 
field from one wire is about 6 microTesla, so yes, you can detect it)


http://msi.nga.mil/MSISiteContent/StaticFiles/HoMCA.pdf
is all about calibrating a ship's compass
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Re: [time-nuts] Crude Survey Technique

[Robert Atkinson]

I'd also go for a compass if you want magnetic north, but then I have a good 
one, a medium landing compass. Mine dates from WWII but they are still made 
http://www.sirs.co.uk/ground/landing_compasses/patt2/landing_resource
These are used to align the standbay and remote reading compasses on aircraft. 
Good to half a degree. If you need better ther is the Watts Datum Compass.
 
Robert G8RPI.
 
 From: Chris Albertson albertson.ch...@gmail.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Thursday, 21 November 2013, 23:28
Subject: Re: [time-nuts] Crude Survey Technique
  

On Thu, Nov 21, 2013 at 11:11 AM, Don Latham d...@montana.com wrote:
 Lord no, John. No red wagon is needed. Use a pole and the equation of
 time, and a good watch or clock. At local noon, a shadow will be a n-s
 line.

How accurate do you need to be?   The above requires a very tall pole
to case a 300 foot long shadow.  Then you have to be quick to measure
because the Earth turns at  .25 degrees per minute.

If you need a very tall pole that is 100% vertical then hang a
weighted rope from a tall support.  Then go to the other end and watch
the seconds tick down.

A GOOD magnetic compass can do this job too.  Easier then finding s
1,000 food tall pole.   The better compasses have some kind of optical
aid for sighting a line.

-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] Crude Survey Technique

[Robert Atkinson]

The simplest ones do it by difference in position from one fix to another. no 
need for a map for True North, just trig. For Magnetic North you need a map 
with variation data. More advanced units have magnetic sensors and 
accelerometers. An interesting question that I once spent some hours discussing 
in a pub (bar) about 20 years ago is how does an inertial navigation unit 
determine True North without the aircraft moving? No magnetic sensors, just a 
self contained black box. We know it did it because we had just finished 
installing one and watched it do it. We worked it out after a few pints ;-) 
Hint, it takes longer the closer to the pole you are. For Magnetic headings you 
still need a table of variations. At least one common aircraft inertial nav 
unit has magvar tables that are several years out of date with the OEM (well 
current IP owner, they bought out the real OEM) say it's not possible to update 
them!

Robert G8RPI.





 From: Neville Michie namic...@gmail.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Thursday, 21 November 2013, 21:46
Subject: Re: [time-nuts] Crude Survey Technique
 

How do the car mounted GPS guidance devices find North?
Is it by deciding which direction you are moving on the map that they have 
stored?
It is amazing how quickly they show the orientation of the map/your direction 
of travel.
Do they have a sensor to register when you turn a corner?
What they do does not seem possible from just a series of position fixes.
cheers,
Neville Michie





On 22/11/2013, at 7:45 AM, tmil...@skylinenet.net wrote:

 If you want true north, set up a camera that has time or bulb shutter at the 
 south end of your property. Put in a marker stake. take a time exposure at 
 night with the camera facing north. If you expose for about 30 minutes, you 
 will get a landscape with the stars rotating around the north star. You can 
 then mark the north location on your property under the north star.
 
 A compass siting can give the mag north.
 
 
 From: time-nuts-boun...@febo.com time-nuts-boun...@febo.com on behalf of 
 Brian Lloyd br...@lloyd.com
 Sent: Thursday, November 21, 2013 2:04 PM
 To: Discussion of precise time and frequency measurement
 Subject: Re: [time-nuts] Crude Survey Technique
 
 On Thu, Nov 21, 2013 at 12:52 PM, johncr...@aol.com wrote:
 
 I wish to establish a north south line on my property to an accuracy of
 +/- 2 degrees.
 Could this be done by loading a T-bolt, Antenna, Power source, and laptop
 into my
 little red wagon? The idea being to find two positions several hundred ft
 apart where either LH or T-bolt Mon report the same latitude? Will either
 of these programs report to sufficient accuracy? The base line would be 300
 ft, though more is possible.I realizes that the T-bolt is not a survey
 device, but I can spend several hours fixing each position if required.
 
 
 True north or magnetic north? In any case, a good lensatic compass and
 knowing your magnetic variation should easily get you to within 2 degrees
 and is a lot easier than doing a survey with your GPS.
 
 
 --
 Brian Lloyd, WB6RQN/J79BPL
 706 Flightline Drive
 Spring Branch, TX 78070
 br...@lloyd.com
 +1.916.877.5067
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Re: [time-nuts] Off-Topic Question -- German Composition Resistors

[Robert Atkinson]

May be a bit of drift and reading back to front. Some years ago we bought a 
quantity of moulded carbon compostion resistors from a top US manufacturer. A 
sample check showed that none of them met the 10% tolerance. The maufacturer 
said bake them for a day two! The resistors then passed. Why not replace them 
with modert types you ask? Type approved equipment with the original designers 
long gone and the current type certificate holder unwilling or unable to 
approve the change. Welcome to the world of aviation where we are still 
supporting equipment designed 50 or more years ago.

Robert G8RPI.





 From: Adrian rfn...@arcor.de
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Thursday, 21 November 2013, 20:53
Subject: Re: [time-nuts] Off-Topic Question -- German Composition Resistors
 

Hi Bruce,
no. Same color code here.
However, certain carbon composition resistors from the 60's/70's are 
notoriously unreliable. The common effect is drift to significantly 
higher values. Besides that, they can get pretty noisy.
Adrian

brucekar...@aol.com schrieb:
 While tracing out a PC board from an instrument manufactured in Germany, I
 quickly discovered the color code on 1/4-watt composition resistors is not
 the same as that commonly used in the US  For example, I would measure
 about 10,000-ohms across a presumably good resistor that appeared to be marked
 2700-ohms.  Has/does Germany used a different code for such parts?
  
 Bruce, KG6OJI
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Re: [time-nuts] powering Trimble Thunderbolt with -5V rather than -12V

[Robert Atkinson]

Hi,
Interesting investigation, thanks for sharing. Another option I have used was 
+12V  +5V  with the -12V rail powered by a 9V output isolated DC-DC converter 
from an old thin ethernet network card. These come in either 5V or 12V input 
and are effecitvely free (you also get 10MHz isolaton transformers filters and 
Balun on most cards). They are the fat 24pin DIL module. A little additional 
filtering may be desirable. So they work on -9V to0. this then just needs a 
+12V +5V disk drive type supply (linear) and the DC-DC converter. I still think 
the Condor / PowerOne HTTA 16W linear open frame supply (e.g. ebay item 
221307930971 no connection) is the best solution though.
 
Robert G8RPI. 
 From: Stewart Cobb stewart.c...@gmail.com
To: time-nuts@febo.com 
Sent: Thursday, 31 October 2013, 6:11
Subject: [time-nuts] powering Trimble Thunderbolt with -5V rather than -12V
  

Executive summary:  you can power a surplus gold Thunderbolt using a
-5V supply in place of a -12V supply, and it will probably work just
fine.

Details:  The manual for Trimble Thunderbolts specifies power supplies
of +5V, +12V, and -12V.  It turns out that power supplies that provide
+5V, +12V, and -5V are easier to obtain locally.  I began to wonder
what circuitry in the Thunderbolt required -12V, and whether it would
run just as well on -5V.  So I took one apart and started probing.

As far as I can tell, the -12V supply goes to only two places.  One is
the negative supply pin for the quad op-amp (LT1014) in the DAC
circuit for the OCXO.  The other is a strange little circuit involving
a 2N3904 (SOT-23 marked 1A) near the 232 driver chip, right next to
the serial port.  This circuit seems to be comparing the -12V input
with one of the charge-pump pins on the 232 chip.  Its output (?)
connects to a test point labeled MON.  I assumed this was
non-critical and decided to ignore it.

The LT1014 op-amp is rated for operation on supply voltage as little
as 5V and as much as 30V (+/- 15V).  The spec sheet says the output
saturates about (1V typical / 3.5V max over temperature) above the
negative supply.  Presumably, if the op-amp is not asked to generate
output voltages lower than -1.5V, it should run fine with a -5V
negative supply.
The only negative voltages I could find, probing around the op-amp
circuit, were generated by AC-coupling digital square waves.  None of
the op-amp outputs were negative.  (My DAC steady-state value was
around +300mV, which appeared many places in the circuit.  Presumably
a slightly negative DAC value would also appear in many places, but as
long as it's greater than -1500mV, it won't matter.)

Armed with theoretical and practical confirmation that this should
work, I tried it.  And, oddly enough, it appears to be working.  Two
different Thunderbolts have been powered by +5/+12/-5 supplies, and
both have settled down and started tracking exactly as one would
expect.  For one, the settled DAC voltage was within a few
millivolts of the value it had on the specified power supplies,
shortly before the change.  The other had not been powered on for a
while and is still settling, but it seems happy.

There is a subtle possibility for concern, in that the sensitive DAC
signals near ground are now about 3.5V away from the center of the
op-amp supply range.  This could theoretically cause increased
distortion, offset, or offset drift due to the larger common-mode
voltage on the op-amp inputs.  In practice, it does not appear to be
an issue.

This note applies to the common surplus Thunderbolts in the
gold-anodized box, with the Trimble-branded OCXO.  All of those I've
tried seem to settle with DAC voltages near zero.  If you try this
with another style of Thunderbolt, you're on your own.

Cheers!
--Stu
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Re: [time-nuts] Trimble replacement part-2

[Robert Atkinson]

Hi Frank,
I would NOT put the spare TB on a PC powersupply. Check out both TB's on the 
bench using decent linear supplies. I don't like using PC supplies on critical 
equipment. They are typically designed for a specific (high) load on one output 
(5V on early ones 12V on more modern) to maintain regulation on the other 
outputs. They are designed down to a cost and are often not great in terms of 
suppressing spikes and surges. You are running a sub 15W TB on a 100-300W PSU. 
And then there is the phase noise issue. Whay put a $30 PSU on $1000 Frequency 
standard? A 3 line analog supply is easy to build at most 2 transformers two 
bridge rectifiers a few capacitors and 3 78xx series regulators. Surplus (or 
new) linear supplies are available, I use a HTAA-16W-AG by Power-One / Condor / 
SL Power,  like ebay items 300956540240 300956540566 ($15 each). Even new from 
Mouser they are under $100. These high quality 100% duty cycle units are 
slightly underated for start-up
 current on the +12V rail, but with virtually no load on the -12V and low load 
on the +5V it works fine. I'm in the UK on 50Hz mains so its worse case, the 
PSU has 20% more capacity on 60Hz.
Bin the switcher!


Robert G8RPI.



 From: Frank Hughes hp_cisco...@yahoo.com
To: time-nuts@febo.com time-nuts@febo.com 
Sent: Saturday, 12 October 2013, 22:49
Subject: [time-nuts] Trimble replacement part-2
 

Hi, 
Well, now I have determined that the TB
is actually bad and/or the goofy PC power brick is no longer making
correct volts. 

http://i180.photobucket.com/albums/x257/fish1_07/am/trimble_trouble_zps70b440a7.png
 

I had one spare Trimble remaining to
replace it with. 
Not sure what model the new one is, the
enclosure is red and a different form factor than the smaller anodized
Aluminum TB that failed. 

New one works fine: 
http://i180.photobucket.com/albums/x257/fish1_07/am/Trimble_replaced_10_12_2013_zps5042b487.png
 

Funny thing, my HP 59309A Clock had
stopped working, I thought it had a failure too, but when a stable
10Mhz signal appeared at the HP input, the ancient HP clock is back
to abby-normal again! 
I should remember that the HP is also a miners canary for the TB...

In a state of delusion, I sent an EM to
Jackson Labs sales to see if they will sell a Fury 
to an individual..can't imagine what
Quan-1 $$$ is going to be... 

73 
Frank 
KJ4OLL
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Re: [time-nuts] trimble antenna connector

[Robert Atkinson]

Hi

Trimble recommend 75R CATV or similar cable for the Thunderbolt as it's lower 
loss (even with the mismatch loss to 50R it's an advantage), hence the F type 
plugs. Adaptors are cheap and available even here in the UK where the F type is 
a fairly new entry into the market. Using 75R cable with F plugs is even easier.

Robert G8RPI.




 From: Eric Garner garn...@gmail.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Friday, 4 October 2013, 17:38
Subject: [time-nuts] trimble antenna connector
 

why do older  thunderbolts use an F connector for the antenna? (the
current version uses a BNC).
It seems like it needlessly complicates installation at a base station.

I've always wondered this.

-- 
--Eric
_
Eric Garner
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Re: [time-nuts] DIY GPS antenna...

[Robert Atkinson]

Hi,
I built a number of the air spaced patch antennas,  
http://www.express-builder.com/docs/gpsant/ , several years ago for APRS 
mobiles and even with older GPS modules (Garmin), they gave usable performance.

Robert G8RPI.





 From: Attila Kinali att...@kinali.ch
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Sunday, 29 September 2013, 18:38
Subject: Re: [time-nuts] DIY GPS antenna...
 

On Sun, 29 Sep 2013 19:00:54 +0200
Attila Kinali att...@kinali.ch wrote:

  That sounds like a pinwheel antenna.  I've wondered how hard it would 
  be to build one, but I've never seen a DIY version and the math is way 
  beyond me.  The only commercial version that I've seen is from 
  Novatel.  Do they control all the patents?
 
 Building one should be fairly easy. Just use standard PCB fabrication
 and you can build the whole structure with high accuracy. The design
 itself is the hard thing to come up with. I think, for us mere mortals
 the only way to come up with something half decent is to use a genetic
 algorithm that goes trough various designs and selects the best one.
 Unfortunately, i'm not aware of any antenna design software suitable
 for such a task.

BTW: if you want to build your own GPS antenna, the easiest designs
are

* Patch antenna 
    If you don't use any ceramic material, it's just two rectangular
    copper plates ontop of eachother with some spacers, although
    bit big. There are IIRC closed formulas to calculate the size
    of the patch and the position of the feed. One example of this
    kind is [1]

* Cross-Dipole antenna
    Like the patch antenna, this one follows the idea of having
    two arms at a right angle, which differ slightly in length.
    Very easy to calculate, but it becomes large and you need more
    free space around it than the patch antenna and probably a ground
    plate as reflector as well. If you dont feel like building this
    one out of wires for the fear of getting the measures wrong, make
    a PCB design with a slit in the middle to put two PCBs at a right
    angle together. The traces on the PCB then form the antenna which
    you just have to solder together.

* Helical antenna
    I haven't had a look at those, but i guess they are not too
    difficult to calculate (there are at least a few ham radio
    designs out there and i'm sure Rothammel has the formulas).
    Some form of platic tube could form as a base material where
    you wind wire around it.
    The clasic 4 wire helical design with a rigid coax core is well
    known and there are quite a few desscriptions out there, e.g. [2]
    And if you are at JPL, you are free to but this antenna into
    a salad bowl ;-)


I would probably prefer the patch or cross dipol antenna made out of
PCB material, such that the bottom of the ground plate PCB would contain
the LNA.

            Attila Kinali



[1] http://www.express-builder.com/docs/gpsant/
[2] http://lea.hamradio.si/~s53mv/navsats/analog.html

-- 
1.) Write everything down.
2.) Reduce to the essential.
3.) Stop and question.
        -- The Habits of Highly Boring People, Chris Sauve
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Re: [time-nuts] Beating 20MHz was Shielding a DAC line

[Robert Atkinson]

Hi Bob,
You say you are not ready to go GPS. I assume you mean a GPSDO. If you have a 
'scope you can use just about any GPS with a 1pps output. trigger the scope 
from the 1pps while monitoring the 20MHz sine wave and adjust for minimum drift 
of the trace. A timing GPS module will be better (you can get a used Oncore UT 
plus for under $20 on ebay) but anything will be better than beating an HF 
signal by ear.
 
HTH,
Robert G8RPI. (too many Bobs  :-) 
 


 From: Bob Albert bob91...@yahoo.com
To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency 
measurement time-nuts@febo.com 
Sent: Friday, 27 September 2013, 2:24
Subject: Re: [time-nuts] Shielding a DAC line
  

This is off topic but I'm unsure how to do it properly.

I am trying to 'discipline' a couple of sources.  I zero beat with 20 MHz WWV 
but can't tell the difference between fading and the beat, so I am stuck in the 
vicinity of 1 Hz possible error.  That's 50 ppb I think.

What can I do to take the next step to bring the oscillators in closer 
agreement?  I am not ready to go GPS or buy a rubidium standard.


Bob




From: Bob Stewart b...@evoria.net
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Thursday, September 26, 2013 6:13 PM
Subject: Re: [time-nuts] Shielding a DAC line


Hi Bob,

I should have mentioned that I added a new 5MHz output, and the coax ran within 
1/8 of the single DAC wire going to the OCXO.  I don't think anything else 
changed, but of course there could be some flake of something on the DAC line 
that I missed.  I put on the RG-174 and I see that it's still locking high.  I 
suppose it could be just that it was a long power cycle to the oscillator.  
Come to think of it, this thing does like to move to a new voltage sometimes 
when I have it off to mess with something.  So, maybe it's just the oscillator 
being cranky.  I haven't had it off for more than just a few seconds in a long 
time.  If I weren't in test and development mode where anomalies are good, I 
think I'd put the old one back in.

Thanks as always,

Bob






 From: Bob Camp li...@rtty.us
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Thursday, September 26, 2013 7:54 PM
Subject: Re: [time-nuts] Shielding a DAC line
 

Hi

I suspect that you have a ground offset between the OCXO's ground return and 
the DAC's ground reference. The signal *should* be DC, Shielding it won't 
hurt, but it really should not help much.  If anything is an issue a simple 
R/C filter at the OCXO pin should nuke it better than coax will.

Bob

On Sep 26, 2013, at 8:09 PM, Bob Stewart b...@evoria.net wrote:

 I made some minor hardware changes to my GPSDO today and I see that it's 
 locked to a new DAC voltage about 21mV higher.  So, I was wondering about 
 shielding the short run to the OCXO.  I have immediately available RG-174 
 and I'm putting that in.  But, should this be some sort of steel shelled 
 semi-rigid coax?  Maybe it's a dumb question, but I thought I'd ask.
 
 Bob - AE6RV
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Re: [time-nuts] Varian 921-0062 ion pump supply question

[Robert Atkinson]

Hi Corby,
What pins are the line and the neutral connected to at the moment? What pins 
are linked?
What you describe is typical of a 110/120/220/240 setup with the windings 
between 1 8 and 29 being the 10V taps. 
You could try connecting a low voltage AC supply (between5 and 15 v from a 
transformer) to the amins input and measuring the transformer input voltages. 
This will give you the voltage ratios and phasing.
I'll try to find the manual online and see where the tap goes.
 
Robert G8RPI.
 


 From: cdel...@juno.com cdel...@juno.com
To: time-nuts@febo.com 
Sent: Thursday, 19 September 2013, 22:56
Subject: [time-nuts] Varian 921-0062 ion pump supply question
  

Here is the deal.

The 4 terminal TX wiring is pretty obvious. (I have a unit with the 4
terminal to compare with)

The 6 terminal I have ohmed out and it is not obvious!

Pins 1 to 3 and 2 to 4 (.5 Ohms) appear to be the 120VAC windings and
hooking them in parallel should do the trick.

As wired for 240 VAC 1 to 3 and 2 to 4 are in series which makes sense.

However when the 4 terminal is wired for 240VAC a wire comes off the
input center tap to provide 120VAC to some circuits in the unit.

The 6 terminal when wired for 240VAC has an extra wire connected to pin
8.

Pin 8 to 1 and pin 9 to 2 show .2 Ohms so they look like maybe taps for a
different input voltage slightly different from 120VAC.

The problem there is that the wire to pin 8 which would logically go to
the center tap as above goes to this pin 8 tap which makes no sense!

Of course it could have been miswired when I got it!

All the manuals I can find by Goggling show the 4 pin TX!

Was hoping someone might have a unit with the 6 pin TX wired for 120VAC
so they could advise me!

Thanks,

Corby

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Re: [time-nuts] Varian 921-0062 ion pump supply question

[Robert Atkinson]

Hi Corby,
I had a look at some circuits and it’s pretty much what I expected. The 120V
tap supplies control relays including the external pressure relay (pin F on
rear panel connector, pin E is neutral) and neon indicators. The supply to the
HV transformer is relay controlled so you would have to bypass that to do the
low voltage power-up trick. The four terminal transformer has odd numbering
with one winding between 1  3 and the other between 2  4. This allows
the same rigid shorting links to be used for both 120 and 240V, one each
between 12 and 34 for 120V and two stacked between 34 for 240V.  The safe 
option would be to apply 12V ac
across 13 with no links and check the voltages and phase on the other windings
and taps. The secondary should be 1/10 of that expected. If it high you need to
use the additional taps on terminals 89. One possibility is that these
taps are an alternative to a tapped secondary for HV adjustment. For 120V input
the extra tap wire should be connected to the input supply so you have line 
voltage across pins E F of the pressure relay connector.
Don’t forget that there is another switch or links on the control PCB for the
small transformer.
 
HTH
Robert G8RPI.

 


 From: cdel...@juno.com cdel...@juno.com
To: time-nuts@febo.com 
Sent: Thursday, 19 September 2013, 22:56
Subject: [time-nuts] Varian 921-0062 ion pump supply question
  

Here is the deal.

The 4 terminal TX wiring is pretty obvious. (I have a unit with the 4
terminal to compare with)

The 6 terminal I have ohmed out and it is not obvious!

Pins 1 to 3 and 2 to 4 (.5 Ohms) appear to be the 120VAC windings and
hooking them in parallel should do the trick.

As wired for 240 VAC 1 to 3 and 2 to 4 are in series which makes sense.

However when the 4 terminal is wired for 240VAC a wire comes off the
input center tap to provide 120VAC to some circuits in the unit.

The 6 terminal when wired for 240VAC has an extra wire connected to pin
8.

Pin 8 to 1 and pin 9 to 2 show .2 Ohms so they look like maybe taps for a
different input voltage slightly different from 120VAC.

The problem there is that the wire to pin 8 which would logically go to
the center tap as above goes to this pin 8 tap which makes no sense!

Of course it could have been miswired when I got it!

All the manuals I can find by Goggling show the 4 pin TX!

Was hoping someone might have a unit with the 6 pin TX wired for 120VAC
so they could advise me!

Thanks,

Corby

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Re: [time-nuts] Varian 921-0062 ion pump supply question

[Robert Atkinson]

Hi Corby,
How's it wired now? Basically it should be two windings in series, say line to 
1, 2 linked to 3 and neutral to 4. To set to 120V leave line and neutral were 
they are and link 2 to 4 and 3 to 1. As a double check for phasing when you 
lift the link between 2 and 3 check for winding resistance between 1 and 2  and 
separately 3 and 4. They should benear identical resistance values. Change tag 
numbers to suit your original wiring.

HTH,
Robert G8RPI.





 From: cdel...@juno.com cdel...@juno.com
To: time-nuts@febo.com 
Sent: Thursday, 19 September 2013, 20:43
Subject: [time-nuts] Varian 921-0062 ion pump supply question
 

Hi,

I'm working on a Varian 921-0062 ion pump controller for the pumps used
in a Maser.

I just got it in and it is wired for 240 VAC and I want 120VAC.

My manual and the ones I can find on line show a power TX with 4 input
terminals which they show how to strap for 240 or 120 VAC.

My unit has TX has 6 terminals 1/2/3/4/8/9.

Does anyone know how to wire this TX for 120 VAC?

Thanks,

Corby Dawson

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Re: [time-nuts] DIY Choke Ring Antennas?

[Robert Atkinson]

Be aware,
Googling helibowl at work may take you to websites selling glassware used for 
recreational purposes that may not be appreciated by the IT police ;-)
 
Robert G8RPI.
 


 From: Jim Lux jim...@earthlink.net
To: time-nuts@febo.com 
Sent: Tuesday, 17 September 2013, 5:31
Subject: Re: [time-nuts] DIY Choke Ring Antennas?
  

On 9/16/13 6:51 PM, Bob Stewart wrote:
 With all the talk about choke rings, and having spent all my pennies 
 elsewhere, I looked around to see if there were any do-it-yourself versions.  
 I found this one: http://www.mauve.gr/var/DIY_Choke_Ring_GPS_Antenna.htm.  
 Is it worth the effort, other than as an experiment?  Are there any other 
 homebrew versions out there that anyone has tried?  Granted, I have no real 
 complaints about the amplified patch I have sitting on my HP stack which is 
 right under a massive central air system, but it sounds like a project after 
 my PLL is finished and my Rb standard is boxed up nicely.

The JPL'ers are fond of the Helibowl.. A helix wound on a plastic cup, 
mounted in a inexpensive mixing bowl, or those things you put under the 
elements/burner in a stove.  I've asked several times about specific 
dimensions and they're always sort of vague: I think it depends on the 
specific model of plastic cup and mixing bowl available at the local 
discount store when they make the antenna.

If you look up the dimensions of the choke rings, you'll see there's a 
fair amount of variability, so the nested straight sided cake pan is 
probably not a bad strategy, as well.





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Re: [time-nuts] Req: Decent GPS Antenna Active/PassiveRecommendation

[Robert Atkinson]

Hi John,
I use one of the 26dB active timing antenna like ebay item 271266449940 or 
170889540720 but a quick look shows fluke.l is selling a 38dB one 300956651110 
that might be good if you have a long antenna run. You don't say what 
receiver(s) you have, but the Thunderbolt needs a gain antenna. It's always 
best to put the gain at the antenna. On the subject of feeders, while the 
systems are 50R impedance, it is common to use 75R cable TV or satellite coax. 
It's cheaper and lower loss at 1.5GHz than common 50R cable. The loss due to 
mismatch is less than the reduced line loss. Trimble rcommend this approach.

HTH,
Robert G8RPI.





 From: David J Taylor david-tay...@blueyonder.co.uk
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Sunday, 15 September 2013, 10:14
Subject: Re: [time-nuts] Req: Decent GPS Antenna Active/PassiveRecommendation
 

Hello David,

Thanks for the pic!

Well, I need something that I can put outside, in the weather, with my
verticals, and other antennas.  I am a Ham radio enthusiast, and I want
something I can properly mount and can be an all-weather device and can
live happily 'in the farm' so to speak.

I should have been more specific.

Thanks Again,
John Westmoreland
AJ6BC - (that's my call sign)
===


Thanks for the clarification, John.  I'm sure others will answer your 
question, but here I have not found the need for an outdoors GPS antenna, 
being located on the top floor of a two-storey building, in a good VHF 
location.  This with one exception - an older Garmin GPS 18 LVC, which had 
the sensitivity of decade-old devices, not the modern chips.  That just sits 
on the sloping roof, actually on the opposite side of the roof from these 
antennas:

  http://www.satsignal.eu/wxsat/atovs/pic_old-and-new.jpg

from:
  http://www.satsignal.eu/wxsat/atovs/index.html

73,
David GM8ARV
-- 
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk 

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Re: [time-nuts] Req: Decent GPS Antenna Active/Passive Recommendation

[Robert Atkinson]

Hi Bob,
Many of the midrange antennas have one or more significant differences from the 
cheap pucks. Firstly they generally have better filtering, many pucks have 
none. This is important if you are co-located with transmitters.  Secondly many 
use quad-helix antenna elements rather than the off-set feed ceramic patches in 
the pucks. The heical elements have better control of the radiation pattern and 
along with a larger radome are less likely to be affected by external 
contamination. I also wonder how the tuning of a cheap ceramic patch holds up 
over the range of temperatures seen by a fixed antenna. Modern receivers 
compensate well for poor antennas, try using an early receiver on an internal 
patch and you won't get great results.

Robert G8RPI.





 From: Bob Camp li...@rtty.us
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Sunday, 15 September 2013, 22:19
Subject: Re: [time-nuts] Req: Decent GPS Antenna Active/Passive Recommendation
 

Hi

Worth noting: 

The mid class antennas are not a lot different electrically than the low 
end antennas. The main differences are mechanical:

1) You get a much more weather tight housing
2) You get a rational way to mount the antenna 
3) There's a connector on it so you can put a good piece of coax on it
4) The housing *may* be more immune to snow / ice buildup and bird nests

RDR Electronics on the usual auction site appears to be selling some nice ones 
at the moment.

Bob

On Sep 15, 2013, at 4:36 PM, Hal Murray hmur...@megapathdsl.net wrote:

 
 j...@westmorelandengineering.com said:
 Well, I need something that I can put outside, in the weather, with my
 verticals, and other antennas.  I am a Ham radio enthusiast, and I want
 something I can properly mount and can be an all-weather device and can live
 happily 'in the farm' so to speak. 
 
 I split GPS antennas into 3 clumps.
 
 At the low cost end are the small mouse or hockey-puck type units, 
 usually with a magnetic mount.  They typically come with 10 or 15 feet of 
 thin (lossy) cable.  Ballpark price is $10.
 
 In the middle are the typical cones that you see on cell phone stations.  The 
 Lucent 26 dB ones are common on eBay.  Ballpark price is $50.  The same or 
 very similar thing is also available with different brand names.  Some of 
 them come with a pipe mounting setup such that the coax and connector is 
 inside the pipe and out of the weather.
 http://www.megapathdsl.net/~hmurray/time-nuts/Lucent-Antenna.jpg
 
 At the top end are the choke ring antennas intended for surveying.  They are 
 mostly out of my price range so I haven't looked carefully.
 
 --
 
 I haven't seen a GPS antenna without an amplifier, but I haven't been 
 looking.  They also include a filter.  See the LightSquared flame-wars for a 
 discussion of filters.
 
 I think the choke ring antennas usually let L1 and L2 through while most 
 others are L1 only.
 
 The other important consideration is the sensitivity of your receiver.  Every 
 couple of years a new generation comes out that is a few dB better than the 
 previous ones.  (Has anybody seen a Moore's Law type graph?)
 
 Modern receivers are sensitive enough to work indoors with a non-fancy 
 antenna, at least most of the time.  YMMV etc, and indoors probably doesn't 
 include buildings with a lot of steel.  It doesn't cost much to try.
 
 If you have an old recycled GPSDO such as a TBolt or Z3801A, the receiver is 
 much less sensitive and a good antenna position helps a lot.  Of course, it 
 also depends upon what you want to do and/or how nutty you are feeling.
 
 There is yet another dimension.  GPS receivers come in two modes: navigation 
 and timing.  Navigation units need 3 or 4 satellites to figure out where (and 
 when) they are located.  The timing units assume they are not moving and that 
 they know their location.  They should be able to maintain timing with only 1 
 satellite.
 
 
 -- 
 These are my opinions.  I hate spam.
 
 
 
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Re: [time-nuts] Thunder Bolt Display...

[Robert Atkinson]

Hi,
I thought one post was OK (just), but by the third advert I thought the 
questions should be asked.
Sorry for lowering the S/N.
 
Robert G8RPI.
 


 From: Burt I. Weiner b...@att.net
To: time-nuts@febo.com 
Sent: Friday, 13 September 2013, 6:08
Subject: [time-nuts] Thunder Bolt Display...
  

Well, I thought it was appropriate for this group.  But, what do I 
know.  I would probably get one except that I don't have a 
Thunderbolt.  Even so, it was interesting to see the video.  Well done, Adam.

Burt, K6OQK

Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California  U.S.A.
b...@att.net
www.biwa.cc
K6OQK 

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Re: [time-nuts] ThunderBolt Display - Update

[Robert Atkinson]

Hi Adam,
If you do not normally monitor this email reflector or contribute to it, why 
are you using it it promote your commecial product?
Are you going to make the circuit and code (or programmed MCUs) available to 
list members?
 
Robert G8RPI.
 


 From: Adam Maurer m...@vklogger.com
To: time-nuts@febo.com 
Sent: Thursday, 12 September 2013, 6:56
Subject: [time-nuts] ThunderBolt Display - Update
  

Hello all

An update:
ThunderBolt Display started shipping over a week ago.
31 out the 50 have already been sold.

I have made a video on the display, and you can see a working example here:
http://www.youtube.com/watch?v=BSSZ6BcggBo

Any new orders for the  “jumbo” sized green and standard sized inverted blue 
variants will incur a 2 week wait, as these LCDs are only ordered in 
as-required.
I do have a number of standard sized green units available for immediate 
shipping though on a first-in basis.

I am away for 3 weeks in October, so if you want a display sooner than later, 
you should consider placing an order in the next few days, as it take 2 weeks 
for the LCDs to arrive.

For more information of this device, please refer to:
http://vk4ghz.com/thunderbolt-display/
You will find the latest revision of User Guide and Tech Supplement PDFs 
available as well.
PayPal is welcome on the proviso I receive the full amount and you take care of 
any PayPal fees, if applicable.
(This changes from one region to another)
One way to avoid fees is to make sure your PayPal account has funds in it, and 
never draw upon other accounts (especially a credit card).

Once these are gone, they are gone, and 130 units will be out there in 12 
countries (so far).

I do not normally monitor this email reflector, so please email me directly, if 
you want to obtain a ThunderBolt Display.


Cheers,
Adam, VK4GHZ
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Re: [time-nuts] ThunderBolt Display - Update

[Robert Atkinson]

Hi Adam,
I have copied this to our outmoded reflector. At least it's low noise and high 
quality.

Sorry but dispite having been a licenced amateur for 35 years, I don't meet 
your 55+ demographic.
I am aware that amateur radio has an aging demographic. That is why I have 
tutored for the UK licence for 30 years with student ages as low as 10. 

If you paid $3k for 50 double sided PTH PCBs you need to find a new supplier.

I HAVE invested my own money in group projects (not time nuts), in one case an 
PIC driven LCD display add on for an instrument. I was able to sell these on 
ebay for $75 and to list/group members for $50. Circuit, source code and Hex 
file are published and freely available. I also supplied programmed PICs on 
request. So you are wrong in your statement I seriously doubt somebody like 
you would (invest in making up kits for a group. I do value my own time which 
is why I don't waste it on email forums full of people who have lots of opinion 
but no knowledge.

You are correct, I don't contribute much to Time Nuts, I'm here to learn. I 
have contributed the odd manual PDF (originals purchased and scanned by myself) 
and some bits and pieces to members off-list.

I also sell support software on PROM for other equipment, again at discount to 
relevant list members and with full details available. Many people do prefer to 
pay me to program devices, but at least I give them the option and assistance 
to do it themselves.


Don't know what you typed into google, but when I put g8rpi in the third item 
was an open design for a low noise high voltage power supply of mine. You don't 
have to waffle on on youtube to contribute! You seem very fond of your voice 
and face. 



You imply your display is not a commercial product. I guess its not as it does 
not appear to comply with C-Tick, FCC or CE requirements :-)


I'm aware of the time and effort required to make webpages, I've had formal 
training on the subject.
I don't have a webpage, I contribute directly to specific groups. I don't need 
to boost my ego online.
Your main website looks like a shop to me. Your other webpage 
http://www.qsl.net/vk4cp/ is interesting
Your other product the Icom Multi-send looks a great design, or not. $79 for 
a PIC 3 Sil relay a few connectors and an undrilled case.

 
On your display, why no circuit? looking at the pictures it has TWO 28 pin 
Microchip devices. If these are both MCUs I don't think much of your coding 
skills My display used a single 14 pin PIC. 

And a rotary SWITCH for mode selection, how quaint and old fashioned. Also why 
the 3.3V regulator? 

You claim 0.02V accuracy. Really? I see no voltage reference and if you are 
using the PICs internal ADC thats only 10 bits so about 0.015V resolution for 
0-15V input. With no other errors that's 0.03V (+_1 LSB) at best. I guess you 
could have a Vref and offset circuit on the other side of the PCB though.
Couldn't you have included your commander functionaliy? This would save users 
from the messing about with programmers that you seem to think they hate (yes I 
know you said you have supplied programmed chips).

Don't know what problem you have with engineers, without them you would not 
have much equipment.
For the record I'm a Chartered Engineer, Member of the Royal Aeronautical 
Society. I've been a licenced aircraft engineer for 30 years and currently 
design avionics and systems. That includes work on VH aircraft, this grumpy old 
engineer may have designed a critical part on the next aircraft you fly on!


I did not initiate a personal attack on somebody, nor did I say that you do 
not contribute anything (I said you did not contribute to the Time nuts list, 
by your own admission you don't). I asked three questions. Obviously these 
touched a nerve.



G'day,

Robert Atkinson CEng MRAeS G8RPI.








 From: Adam Maurer m...@vklogger.com
To: Robert Atkinson robert8...@yahoo.co.uk 
Sent: Thursday, 12 September 2013, 13:13
Subject: Re: [time-nuts] ThunderBolt Display - Update
 


Robert, I don’t bother with email reflectors, because they are too last 
century.
email reflectors are ok if you are 55+, but they do not do anything 
positive to engage the much needed younger demographic into ham radio.
 
In case you haven’t noticed, ham radio is literally dying of old age.
Do you honestly think younger people with smartphone these can get 
interested in these 1990’s text based email reflectors?
They want something more engaging these days.
I’m sorry (for you) that your demographic fails to appreciate this.
 
I posted about the display because it was suggested by another ham (who is 
a timenuts member) that I might be able to help others with a solution.
Quite a few timenuts members now have this display, and they absolutely 
like it.
 
The fact that you have this expectation that everything will be served on a 
silver platter for nothing, and obviously place ZERO value on your own time to 
develop something like

Re: [time-nuts] First frequency counter

[Robert Atkinson]

Hi Edesio,
Welcome to the group. The HP 5316A you are looking at is an excellent little 
counter. While not up to extreme time nut standards, they work well and in my 
opinion would make a much better first counter than (say) one of the modern low 
end (not known brand) new counters or microcontroller based modules/kits. I 
have one and it gets as much use as my 5370B. It's not rack bound for starters. 
While small it has the features of a full size universal counter. If the 
auction goes much higher it may be worth looking at dealers. I can get a 5316B 
with HPIB in the UK for under 100 UK pounds.
 
Robert G8RPI.
 


 From: Edesio Costa e Silva time-n...@tardis.net.br
To: time-nuts@febo.com 
Sent: Friday, 6 September 2013, 12:26
Subject: [time-nuts] First frequency counter
  

Hi Folks!

I am following the time-nuts for sometime but this is the first time I post
a message and I hope it is not off-topic.

As I live in Brazil, I can not find used equipment in the local market. My
(only?) option is to import some. Since money is always a scarce resource
and the shipping costs from U.S. are very high, I must opt for some small,
light and old equipment. Would this one
(http://www.ebay.com/itm/231044866809) be a nice option for a first
frequency counter / time interval counter? Feel free to suggest alternatives.

Thanks in advance,

Edésio

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Re: [time-nuts] NOT Lady Heather without a PC

[Robert Atkinson]

Sorry for confusion caused by my using the L H words :-) it's called 
Thunderhead and is a lot cheaper than some solutions if you just want a desktop 
monitor or can hack an iPaq handheld into your Thunderbolt's case.
Details including complied EXE for PocketPC and source code is 
herehttp://fuzzythinking.com/projects/thunderhead/

Robert G8RPI.
 


 From: Chris Albertson albertson.ch...@gmail.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Monday, 19 August 2013, 5:00
Subject: Re: [time-nuts] Lady Heather without a PC
 

On Sun, Aug 18, 2013 at 6:36 PM, Didier Juges shali...@gmail.com wrote:

 Go up about 7 or 8 messages.
 It is not a version of Lady Heather for the PocketPC, it is a monitor
 software for the Thunderbolt that runs on certain PocketPC (those like the
 iPaq that have a hardweare serial port). It is very far from the extended
 functionality of Lady Heather, but useful as a health indicator.


Got a link to the source, it could serve as a start

-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] Lady Heather without a PC

[Robert Atkinson]

Sorry to reply to my own post. 
I was wrong on the name of the PocketPC software. It's called Thunderhead see 
http://fuzzythinking.com/projects/thunderhead/

Robert G8RPI.



 From: Robert Atkinson robert8...@yahoo.co.uk
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Thursday, 15 August 2013, 21:17
Subject: [time-nuts] Lady Heather without a PC
 

Hi Chris,
I've posted this before, but it's worth saying again. I use the PocketPC 
version of Lady Heather on an IPAQ. These are available for next to nothing on 
Ebay and can run in a dock on the bench or you can gut it and embed it in a 
cased Thunderbolt. worn out batteries are not an issue as we have constant 
power available. They just need 5V. One with an SD card slot is good so you 
don't have to re-load the code from a PC if the power does go out.


Robert G8RPI.



From: Chris Albertson albertson.ch...@gmail.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Wednesday, 14 August 2013, 18:36
Subject: Re: [time-nuts] ThunderBolt Display


What was the problem you found.  Other then a new to you platform?  I'm
trying to understand why reading serial data would be hard.

An advantage of the Adruino is that you don't need to make a PCB.  Even if
you want to do something like add a graphical display or and SD card for
logging they just plug in, no solder required.

Of course the pre-buillt display is even easier but can't be modified.

One of my loner term goals is to move lady heather like functions onto a
small uP based device.  It seems wasteful to use a PC for this.


On Wed, Aug 14, 2013 at 10:16 AM, Russ Ramirez russ.rami...@gmail.comwrote:

 Yeah, after trying to (reliably) get the time out of the pertinent TSIP
 message using an Arduino UNO, I can understand your statement Adam about
 the Arduino approach. It kinda works, but it felt like I was fighting the
 implementation of the controller card and that I should cut-over to my own
 solution using an Atmel, PIC or TI chip that I could just load C code into.
 One of this lists members gave me the code I needed, so ironically using
 the UNO made the project more difficult.

 Russ
 K0WFS
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Re: [time-nuts] Lady Heather without a PC

[Robert Atkinson]

Hi,

This is not my software. See http://fuzzythinking.com/projects/thunderhead/
I just used the complied file, but the source code is there of you want 
to change it. The iPAQ I built in was an H2200 series running PocketPC 
2002. I've also ran it on a H3900 series (H3950) running PocketPC 2003. I used 
an SD card to store the exe file.  A quick check on ebay shows 
2200 iPAQs on buy it now for $25. 

Robert G8RPI.


 From: Chris Albertson albertson.ch...@gmail.com
To: Robert Atkinson robert8...@yahoo.co.uk; Discussion of precise time and 
frequency measurement time-nuts@febo.com 
Sent: Friday, 16 August 2013, 19:44
Subject: Re: [time-nuts] Lady Heather without a PC
 


What OS runs on the IPAQ?  

Did you have to re-build LH from source?

Edit:  OK now I see you are running some other software called thunderhead.   
Same questions apply



On Thu, Aug 15, 2013 at 1:17 PM, Robert Atkinson robert8...@yahoo.co.uk wrote:

Hi Chris,
I've posted this before, but it's worth saying again. I use the PocketPC 
version of Lady Heather on an IPAQ. These are available for next to nothing on 
Ebay and can run in a dock on the bench or you can gut it and embed it in a 
cased Thunderbolt. worn out batteries are not an issue as we have constant 
power available. They just need 5V. One with an SD card slot is good so you 
don't have to re-load the code from a PC if the power does go out.


Robert G8RPI.



 From: Chris Albertson albertson.ch...@gmail.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Wednesday, 14 August 2013, 18:36
Subject: Re: [time-nuts] ThunderBolt Display


What was the problem you found.  Other then a new to you platform?  I'm
trying to understand why reading serial data would be hard.

An advantage of the Adruino is that you don't need to make a PCB.  Even if
you want to do something like add a graphical display or and SD card for
logging they just plug in, no solder required.

Of course the pre-buillt display is even easier but can't be modified.

One of my loner term goals is to move lady heather like functions onto a
small uP based device.  It seems wasteful to use a PC for this.


On Wed, Aug 14, 2013 at 10:16 AM, Russ Ramirez russ.rami...@gmail.comwrote:

 Yeah, after trying to (reliably) get the time out of the pertinent TSIP
 message using an Arduino UNO, I can understand your statement Adam about
 the Arduino approach. It kinda works, but it felt like I was fighting the
 implementation of the controller card and that I should cut-over to my own
 solution using an Atmel, PIC or TI chip that I could just load C code into.
 One of this lists members gave me the code I needed, so ironically using
 the UNO made the project more difficult.

 Russ
 K0WFS
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--

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Redondo Beach, California
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Redondo Beach, California 
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[time-nuts] Lady Heather without a PC

[Robert Atkinson]

Hi Chris,
I've posted this before, but it's worth saying again. I use the PocketPC 
version of Lady Heather on an IPAQ. These are available for next to nothing on 
Ebay and can run in a dock on the bench or you can gut it and embed it in a 
cased Thunderbolt. worn out batteries are not an issue as we have constant 
power available. They just need 5V. One with an SD card slot is good so you 
don't have to re-load the code from a PC if the power does go out.


Robert G8RPI.



 From: Chris Albertson albertson.ch...@gmail.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Wednesday, 14 August 2013, 18:36
Subject: Re: [time-nuts] ThunderBolt Display
 

What was the problem you found.  Other then a new to you platform?  I'm
trying to understand why reading serial data would be hard.

An advantage of the Adruino is that you don't need to make a PCB.  Even if
you want to do something like add a graphical display or and SD card for
logging they just plug in, no solder required.

Of course the pre-buillt display is even easier but can't be modified.

One of my loner term goals is to move lady heather like functions onto a
small uP based device.  It seems wasteful to use a PC for this.


On Wed, Aug 14, 2013 at 10:16 AM, Russ Ramirez russ.rami...@gmail.comwrote:

 Yeah, after trying to (reliably) get the time out of the pertinent TSIP
 message using an Arduino UNO, I can understand your statement Adam about
 the Arduino approach. It kinda works, but it felt like I was fighting the
 implementation of the controller card and that I should cut-over to my own
 solution using an Atmel, PIC or TI chip that I could just load C code into.
 One of this lists members gave me the code I needed, so ironically using
 the UNO made the project more difficult.

 Russ
 K0WFS
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-- 

Chris Albertson
Redondo Beach, California
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[time-nuts] Distribution Amp 75R socket compatability

[Robert Atkinson]

Hi Dave,
The old thin pin 75R BNC sockets are rare these days. Most equipment now uses 
intermateable sockets that use the same size contact as 50R but with reduced 
diameter dielectric to maintain the impedance match. Fully compatible with 50R 
without damage. The only small drawback is that the old thin pin plugs (if you 
have any) may not make good contact.

HTH,
Robert G8RPI.





 From: Dr. David Kirkby drkir...@gmail.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Thursday, 8 August 2013, 12:08
Subject: Re: [time-nuts] Rb video
 

On 6 August 2013 09:37, Raj vu2...@gmail.com wrote:
 Found this on Hack-a-day

 http://www.youtube.com/watch?v=chrzrod3tQY

 Cheers

 --
 Raj, VU2ZAP

Interesting video. I decided to but one of the distribution amps. I
already have the rubidium. There were a few things that struck me in
the video.

1) Having a PIC to control an LED seems a bit OTT. Personally I'd just
stick a second LED - one as a power indicator, the other as a lock
indicator, rather than make it flash when warming up, and solid when
locked.

2) If one does have a flashing LED, it would be better if it is
slower, in case there are any epilepitcs about. As someone who suffers
from photosensitive epilepsy, I would not want it flashing any faster
than 1 Hz. He should just about be ok, but I'd feel a bit happier if
it was slower.

3) I'm not really convinced there is a need to change the output
impedance from 75 to 50 Ohms. The impedance mis-match is pretty small.

4) More concerning to me would be the fact the output connectors are
75 Ohm, and so would be damaged with the larger male pin of a 50 Ohm
connector. I guess one might get away with it given one is not going
to be disconnecting this a lot, but I think I'd buy 75 Ohm BNC plugs
to put on one end of the cable, and 50 Ohm BNC plugs on the other end,
sticking a bit of heatshrink on the 75 Ohm end of the cable so I know
they are not standard BNC cables.
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Re: [time-nuts] 5MHz x 10MHz

[Robert Atkinson]

Hi
Most of the British Racal standards are 5MHz. It may well have been down to 
what was the best performance of the nationally avilable crystals. Everthing is 
a compromise.
It is easy to double a 5MHz output to 10MHz. One way is to pass it through a 
bridge rectifier (high speed diodes of course) and then filter it. old 10Mbs 
thin ethernet filters from network cards work well. Check the archives and do 
a websearch.


Robert G8RPI.




 From: Bob Camp li...@rtty.us
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Friday, 2 August 2013, 20:12
Subject: Re: [time-nuts] 5MHz x 10MHz
 

Hi

It may well have been teamed up with a piece of Russian designed equipment.

Bob

On Aug 2, 2013, at 2:40 PM, Euclides Chuma eucli...@w2c.com.br wrote:

 Hi,
 
 I thank all for your responses.
 
 My question arose because I bought a TFL Rubidium Standard and the signal 
 output is 5 MHz. It is a great rubidium standard so I dont understand the 
 reason of the 5 MHZ signal output since the 10 MHz is the common standard.
 
 Best regards
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Re: [time-nuts] More pictures of the mystery Collins Ru

[Robert Atkinson]

PS has anyone done any PIC Have Quick stuff?
If I told you I'd have to shoot you ;-)

Robert.




 From: Brooke Clarke bro...@pacific.net
To: time-nuts@febo.com 
Sent: Sunday, 28 July 2013, 23:58
Subject: Re: [time-nuts] More pictures of the mystery Collins Ru
 

Hi:

The military UHF voice radio scrambling depends on accurate time, hence the 
Have Quick (and follow on programs) time 
transfer standard.
Rb standards were used to maintain that time in the early days.

The O-1814 Rb standard was used to keep time on the ground accurate so that 
when a plane flew in from far away the 
crypto would be in sync.
http://www.prc68.com/I/O1814.shtml

PS has anyone done any PIC Have Quick stuff?

Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html

Brooke Clarke wrote:
 Hi:

 I think (3).  See:
 http://en.wikipedia.org/wiki/TACAMO
 http://en.wikipedia.org/wiki/Ground_Wave_Emergency_Network - some converted 
 to DGPS

 Have Fun,

 Brooke Clarke
 http://www.PRC68.com
 http://www.end2partygovernment.com/2012Issues.html

 Robert Atkinson wrote:
 Hi Tim,
 Three possible reasons for needing a Rb standard,
 1/ Coherent detection with a local clock
 2/ Hyperbolic navigation (local reference improves the fix and holdover)
 3/ Secure communications.

 Robert G8RPI




 
   From: Tim Shoppa tsho...@gmail.com
 To: Discussion of precise time and frequency measurement time-nuts@febo.com
 Sent: Sunday, 28 July 2013, 15:25
 Subject: Re: [time-nuts] More pictures of the mystery Collins Ru

 Googling a little bit, I find several references to a Collins rubidium
 package AFS-81 for airborne survivable VLF communications in the 60's
 (predating this unit by maybe two decades). Still trying to wrap my head
 around why that would need rubidium unless it was an airborne WWVB
 replacement or something.

 Googling also turned up the modern Rockwell-Collins 617A-1 VLF amp which
 seems to be a dinky solid state unit that is rated at a third of a
 megawatt. Still having a hard time wrapping my mind around that! Maybe I'm
 off by 2 or 3 orders of magnitude or the picture is just the control head,
 the real amplifier is the size of a building. A third of a megawatt must be
 the size of the fixed transmitters used for VLF submarine communications.

 Tim N3QE


 On Sun, Jul 28, 2013 at 9:40 AM, Pete Lancashire 
 p...@petelancashire.comwrote:

 maybe I should read things more often .. yikes I need a vacation


 On Sun, Jul 28, 2013 at 7:01 AM, George Dubovsky n4ua...@gmail.com
 wrote:

 Well, the outside label does claim it was made by GENRAD... ;-)

 73,

 geo - n4ua


 On Sat, Jul 27, 2013 at 9:24 PM, Pete Lancashire 
 p...@petelancashire.com
 wrote:

 https://plus.google.com/u/0/photos/111617808980322733757/albums/5890266601277045697
 The board with the edge connector was inside the same bag the
 connector was in, the bag was taped to the unit.

 I pulled the ends off first, but was immediately stopped with foam, it
 is
 glued in place.
 Then when I finally got the lid with all the screws off, all there is,
 is
 one board covered in potting compound.

 The compound breaks away pretty easily. One can see where a couple
 parts
 were
 replaced and there soft RTV was used. There are two precision resistors
 in
 that area.

 The biggest surprise is the General Radio logo on the board !

 goo.gl/1XGG2F
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Re: [time-nuts] More pictures of the mystery Collins Ru

[Robert Atkinson]

Not true,
Many aircraft OMEGA / VLF navigation systems used Rb clocks. Most if not all 
the FRKs on the surplus market with the 10MHz output on the multipole connector 
rather than a SMA came from OMEGA / VLF units. I used to fix the systems.

Robert G8RPI.





 From: Max Robinson m...@maxsmusicplace.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Sunday, 28 July 2013, 23:24
Subject: Re: [time-nuts] More pictures of the mystery Collins Ru
 

If they needed an airborne rubidium standard it must have been for digitally 
scrambled communications.  That has been around since the 60s.

Regards.

Max.  K 4 O DS.

Email: m...@maxsmusicplace.com

Transistor site http://www.funwithtransistors.net
Vacuum tube site: http://www.funwithtubes.net
Woodworking site 
http://www.angelfire.com/electronic/funwithtubes/Woodworking/wwindex.html
Music site: http://www.maxsmusicplace.com

To subscribe to the fun with transistors group send an email to.
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- Original Message - 
From: Tim Shoppa tsho...@gmail.com
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com
Sent: Sunday, July 28, 2013 9:25 AM
Subject: Re: [time-nuts] More pictures of the mystery Collins Ru


 Googling a little bit, I find several references to a Collins rubidium
 package AFS-81 for airborne survivable VLF communications in the 60's
 (predating this unit by maybe two decades). Still trying to wrap my head
 around why that would need rubidium unless it was an airborne WWVB
 replacement or something.

 Googling also turned up the modern Rockwell-Collins 617A-1 VLF amp which
 seems to be a dinky solid state unit that is rated at a third of a
 megawatt. Still having a hard time wrapping my mind around that! Maybe I'm
 off by 2 or 3 orders of magnitude or the picture is just the control head,
 the real amplifier is the size of a building. A third of a megawatt must 
 be
 the size of the fixed transmitters used for VLF submarine communications.

 Tim N3QE


 On Sun, Jul 28, 2013 at 9:40 AM, Pete Lancashire 
 p...@petelancashire.comwrote:

 maybe I should read things more often .. yikes I need a vacation


 On Sun, Jul 28, 2013 at 7:01 AM, George Dubovsky n4ua...@gmail.com
 wrote:

  Well, the outside label does claim it was made by GENRAD... ;-)
 
  73,
 
  geo - n4ua
 
 
  On Sat, Jul 27, 2013 at 9:24 PM, Pete Lancashire 
 p...@petelancashire.com
  wrote:
 
  
  
 
 https://plus.google.com/u/0/photos/111617808980322733757/albums/5890266601277045697
  
   The board with the edge connector was inside the same bag the
   connector was in, the bag was taped to the unit.
  
   I pulled the ends off first, but was immediately stopped with foam, 
   it
 is
   glued in place.
   Then when I finally got the lid with all the screws off, all there 
   is,
 is
   one board covered in potting compound.
  
   The compound breaks away pretty easily. One can see where a couple
 parts
   were
   replaced and there soft RTV was used. There are two precision 
   resistors
  in
   that area.
  
   The biggest surprise is the General Radio logo on the board !
  
   goo.gl/1XGG2F
   ___
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Re: [time-nuts] More pictures of the mystery Collins Ru

[Robert Atkinson]

Hi Tim,
Three possible reasons for needing a Rb standard,
1/ Coherent detection with a local clock
2/ Hyperbolic navigation (local reference improves the fix and holdover)
3/ Secure communications.

Robert G8RPI





 From: Tim Shoppa tsho...@gmail.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Sunday, 28 July 2013, 15:25
Subject: Re: [time-nuts] More pictures of the mystery Collins Ru
 

Googling a little bit, I find several references to a Collins rubidium
package AFS-81 for airborne survivable VLF communications in the 60's
(predating this unit by maybe two decades). Still trying to wrap my head
around why that would need rubidium unless it was an airborne WWVB
replacement or something.

Googling also turned up the modern Rockwell-Collins 617A-1 VLF amp which
seems to be a dinky solid state unit that is rated at a third of a
megawatt. Still having a hard time wrapping my mind around that! Maybe I'm
off by 2 or 3 orders of magnitude or the picture is just the control head,
the real amplifier is the size of a building. A third of a megawatt must be
the size of the fixed transmitters used for VLF submarine communications.

Tim N3QE


On Sun, Jul 28, 2013 at 9:40 AM, Pete Lancashire p...@petelancashire.comwrote:

 maybe I should read things more often .. yikes I need a vacation


 On Sun, Jul 28, 2013 at 7:01 AM, George Dubovsky n4ua...@gmail.com
 wrote:

  Well, the outside label does claim it was made by GENRAD... ;-)
 
  73,
 
  geo - n4ua
 
 
  On Sat, Jul 27, 2013 at 9:24 PM, Pete Lancashire 
 p...@petelancashire.com
  wrote:
 
  
  
 
 https://plus.google.com/u/0/photos/111617808980322733757/albums/5890266601277045697
  
   The board with the edge connector was inside the same bag the
   connector was in, the bag was taped to the unit.
  
   I pulled the ends off first, but was immediately stopped with foam, it
 is
   glued in place.
   Then when I finally got the lid with all the screws off, all there is,
 is
   one board covered in potting compound.
  
   The compound breaks away pretty easily. One can see where a couple
 parts
   were
   replaced and there soft RTV was used. There are two precision resistors
  in
   that area.
  
   The biggest surprise is the General Radio logo on the board !
  
   goo.gl/1XGG2F
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Re: [time-nuts] GPS Spoofing

[Robert Atkinson]

It seems you can't rely on the human backup. The UK Marine accident 
Investigation Branch Has recorded numerous accidents due to poor lookout. See
http://www.maib.gov.uk/cms_resources.cfm?file=/KarinSchepersReportWeb.pdf
http://www.maib.gov.uk/cms_resources.cfm?file=/CoastalIsle.pdf
http://www.maib.gov.uk/cms_resources.cfm?file=/Beaumont.pdf
http://www.maib.gov.uk/cms_resources.cfm?file=/Seagate_ReportWeb.pdf
for recent examplesThe other problem is that AIS, a significant anti-collision 
aid, relies on GPS and is susceptable to spoofing.

Robert G8RPI.



 From: Chris Albertson albertson.ch...@gmail.com
To: j...@quikus.com; Discussion of precise time and frequency measurement 
time-nuts@febo.com 
Sent: Saturday, 27 July 2013, 4:18
Subject: Re: [time-nuts] GPS Spoofing
 

I boat?  The backup is a competent captain.  He'd see the compass heading
move and quickly disengage the autopilot.   I had a boat for years  I'd
notice a 5 degree change.  Mine was a sailboat so I'd be more sensitive to
heading changes than a power boater but still the human is the backup.

Most autopilots don't directly follow GPS, they use GPS to determine a
heading, follow it then use GPS to detect drift and re-compute the heading.
the heading would be held by a compass sensor in a low-cost setup or in a
larger setup a lazer ring gyro backed up by a compass.     So a spoofed GPS
would cause the autopilot to think there was a bigger crooswnd or current
and make a bigger heading change.

I bet you could hijack a drone not a manned vehicle the pilot is trained to
monitor the automation and he'd very quickly turn it off thinking it was
broken.






On Fri, Jul 26, 2013 at 8:41 AM, J. Forster j...@quikus.com wrote:

 Prof. Humphry from Texas just reported being able to spoof GPS in the Med
 and take over the nav system of a luxury yacht. He's done this before with
 a drone in the US.

 LORAN as a backup, at least?

 -John

 ==



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-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] Thunderbolt SMPS question

[Robert Atkinson]

Hi Chris,
See http://www.leapsecond.com/pages/tbolt/power.htm and 
http://www.leapsecond.com/pages/tbolt/noise.htm
I use a Condor / PowerOne HTAA-16W triple output linear. Technically it low on 
current for the +12V, but as full current is only drawn during warm up and the 
-12V is virtually unloaded, it copes well and is nice and quiet.

Robert G8RPI. 





 From: Chris Wilson ch...@chriswilson.tv
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Thursday, 18 July 2013, 11:55
Subject: [time-nuts] Thunderbolt SMPS question
 



  18/07/2013 11:47

I have been chasing a really awkward BT ADSL line noise / line drop
issue for weeks. In the end I realised why connecting to the BT master
socket with an extension cable to the router stopped the issues, yet
connecting the original twisted pairs BT cable brought it back I
had installed a Thunderbolt on the roof and its SMPS was behind a
studded wall in my upstairs office, right near the BT jack, with the
cable running *right* by. I *THINK* either the TB itself, its power
supply that came with it from China, or just possibly a 5V SMPS I use
to power one of David Partridge's divider boards, also next to the TB
power supply is the culprit. The 5V SMPS is just a wall wart, but
regulated and branded. I can easily find another, or even build a
little linear supply for it. I don't think the divider board itself is
the cause.


However, I am unsure just what, and how critical, the demands of the TB
are. Has anyone had this sort of issue with a TB power supply, or had
cause to either find another, or find an alternative? I am not yet
sure if the PS is a sealed up box, or if a repair may be an option. Any
advice please? Thanks.

-- 
       Best Regards,
                   Chris Wilson.
mailto: ch...@chriswilson.tv

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Re: [time-nuts] ADSL in UK was Thunderbolt SMPS question OT

[Robert Atkinson]

Hi Chris,
It is very likely that the cause of interference pick-up (not the actual 
source) is BT's odd wiring scheme. The extensions use a third wire for the 
ringing signal. This unbalances the wiring making pick-up more likely on 
extensions. The ringing signal is basically just the incomming line B DC 
blicked with a 1.8uF capacitor. This is only required for old phones with 
mechanical ringers. Try disconnecting the ring wire at the master socket. It's 
connected to terminal 3 and should be Orange with White bands. Leave just 
terminals 2 and 5 (Blue with White bands and White with bands) connected to the 
extension sockets. Even if you are not having trouble this will often produce a 
substantial increase in speed. See 
http://www.wppltd.demon.co.uk/WPP/Wiring/UK_telephone/uk_telephone.html for 
info on phone wiring.

Robert G8RPI.




 From: Chris Wilson ch...@chriswilson.tv
To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com 
Sent: Thursday, 18 July 2013, 18:28
Subject: Re: [time-nuts] Thunderbolt SMPS question
 



 Hi

 It's also likely to have issues if you don't have something between -7 and
 -13 on the V- supply. Current is low (10ma?). A good linear regulator is
 useful on the +12. The +12 rail drops back to  200 ma under most conditions
 once the oven has warmed up.

 Bob




18/07/2013 18:26

Thanks Bob, Robert and Azelio. I spoke too soon, the damned noise is
back with the TB and divider supplies unplugged. I was really hopeful
I'd cracked it there. Time to call my ISP to get BT out. Living in the
sticks satellite internet is appealing right now :)

-- 
       Best Regards,
                   Chris Wilson.

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Re: [time-nuts] Lead acid battery noise levels - super caps

[Robert Atkinson]

Interesting idea. 
Capacity equates to about 115mAH (.310WH / 2.7V) and thats to zero output, so 
not an endurance option.
 
Robert G8RPI



From: David t_list_1_o...@braw.co.uk
To: time-nuts@febo.com 
Sent: Thursday, 11 July 2013, 22:17
Subject: Re: [time-nuts] Lead acid battery noise levels


Its just over 10 years since I've used lead acid batteries as the lo 
noise power option for a low phase noise reference source use in the 
development of a jitter measurement instrument , we used discrete regs 
rather than  '317s etc, it worked fine but I can't pass on the details. 
I still have the reference without the batteries which went for 
recycling long ago, the possible new twist I've not seen noise data on 
is not batteries but Ultracapacitors intended for regenerative breaking:

http://www.maxwell.com/products/ultracapacitors/products/d-cell-series

It's nice to try something new and being new might be a way to sidestep 
environmental concerns.

Regards
David

 Message: 7

Date: Thu, 11 Jul 2013 11:48:39 -0600 (MDT)
From: Don Lathamd...@montana.com
To: Discussion of precise time and frequency measurement
    time-nuts@febo.com
Subject: Re: [time-nuts] Lead acid battery noise levels
Message-ID:
    454263ca57f18f7fee4702b190662d3e.squir...@webmail.montana.com
Content-Type: text/plain;charset=iso-8859-1

But Hg batteries are So Moot! We're simply not allowed to have them or
make them. Nanny won't have them in the house.
I have a couple of Accutron clocks that would love to see a mercury cell.



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Re: [time-nuts] How dangerous if a Rb lamp broken?

[Robert Atkinson]

Hi,
Not quite,  The raduim is still very active. The glow stops because the ZnS 
breaks down. The light emissson relies on the crystaline structure of the ZnS 
plus a small amount of doping, typically silver. The alpha particles break down 
the crytaline structrure causing the glow to weaken. Most will still show a 
very faint glow if you let your eyes adapt in complete darkness for about 15 
minutes.
One reason why stopped hands can darken the srystal of a watch more than the 
numerals is distance. Inverse square law applies, thae hands are about half the 
distance so four tine the radiation. Alphs leaves are even lower as even a inch 
or two of air will stop them.
 
Robert G8RPI.



From: Bill Hawkins b...@iaxs.net
To: 'Discussion of precise time and frequency measurement' 
time-nuts@febo.com; 'Tom Miller' tmil...@skylinenet.net 
Sent: Thursday, 11 July 2013, 0:11
Subject: Re: [time-nuts] How dangerous if a Rb lamp broken?


Since this thread doesn't appear to have a half-life, perhaps this needs
some explanation.

The zinc sulfide fluoresces when an atom or more of radium decays. The
fluorescence will still occur in the presence of ionizing radiation. The
radium, OTOH, is nearly dead. Probability says that some number of atoms
will leave their radioactive state and become inert (Lead? I haven't got
time to look it up so I'll share my ignorance with you. Someone will
correct me and the thread will never die.) The rate at which a mass of
radium becomes inert is expressed as its half-life, which is the TIME
that it takes for half of the remaining radium to become inert. The
decay is exponential, as are so many natural things. You'll need a
sensitive Geiger counter to see if there's any life left in the radium.
Or you could expose the watch to a photomultiplier in total darkness to
see if it scintillates.

In other words, it doesn't burn out.

Bill Hawkins


-Original Message-
From: Chuck Harris
Sent: Wednesday, July 10, 2013 5:29 PM

The dial is painted, the hands are actually metal frame, and the
luminous paint is a wax that is put on the hand kind of like a soap
bubble.

The luminous material in the paint is very dead, as the hands and digits
no longer glow at all.  I guess there is a limit to how long ZnS:Cu can
take the exposure and still glow.

-Chuck Harris


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Re: [time-nuts] Lead acid battery noise levels

[Robert Atkinson]

I'd guess that NiMH cells would be similar to Nicads. Cadmium has been banned 
in the EU, except where it is essential. The power tool manufacturers 
successfully negotiated an exemption, so they are still available. 
I did note that the paper only considered Johnson and shot noise. The very low 
frequency noise caused by electrochemical / electrolyte movement was not 
addressed.

Robert G8RPI.





 From: David Kirkby david.kir...@onetel.net
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Thursday, 11 July 2013, 15:25
Subject: Re: [time-nuts] Lead acid battery noise levels
 

On 11 July 2013 05:47, Mark Spencer mspencer12...@yahoo.ca wrote:
 Eric:

  http://tf.nist.gov/general/pdf/1133.pdf

 discusses the noise levels of various batteries.

 Regards
 Mark S


Sod's Law comes into play here. From a quick read of that, it seems
NiCd are best, but they are being phased out. I was told they were
banned in Europe, but I don't know if that is true. I'm pretty sure
I've seen NiCd tools in the local DIY store, so I doubt it is true.

Dave
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Re: [time-nuts] How dangerous if Rb lamp broken?

[Robert Atkinson]

Hi Hui,
This is a little off-topic for time nuts, but here goes. the 
Becquerel is a measurement of radioactivity, 1Bq being one decay per 
second. Bg/gm is specific activity so if you have 1g of material with a 
specific activity of 200Bq/g you will have 200 decays per second. We 
need to use this as not all the Rb in a lamp is Rb 87 and the weight 
quoted includes it all. The Sievert is a measurement of effective dose. 
It depends on time, quantity of radioactive material, type and energy of
 radiation emitted, distance and the organ exposed. It is not a simple 
calculation or conversion. As Rb87 is a beta emitter with a maximum 
energy of 272 keV, it will only produce localised effects. externally it
 will only cause skin exposure and you would need megabecquerels in 
direct contact to cause something like a sunburn. Anything else
 would need internal exposure.
Rb87 is of so little concern that the 
standard dose rate calculation program I use does not even list it. 
Chemically Rb is similar to potassium, K, which is essential to humans. 
 Natural K contains 0.0117% of the radioactive isotope K40. A typical 
70kg human male is 0.2%K so has more than 3000Bq of K40.  So if you 
swallowed 2mg of the Rb from a bulb AND the body absorbed ALL of it, the
 total additional dose would be less than 0.1% of that you are getting 
from the natural K in your body. In practice it would be even less 
because your body would not absorb it all and that it did absorb would 
probably displace some K. Intact Rb cells cells have on detectable 
external radiation. My half gram estimate came from a web search of peer
 reviewed articles. 
The US occupational ingestion limit is 1mCi or 
37000Bq per year. Inhallation is twice that. US labs can discharge water
 to the sewer with 370Bq/liter of Rb87  
Rb cells are perfectly safe for all practical purposes. An injury from the 
broken glass is probably much more of a risk!


HTH,Robert G8RPI.



 From: Hui Zhang ba...@163.com
To: Robert Atkinson robert8...@yahoo.co.uk; Discussion of precise time and 
frequency measurement time-nuts@febo.com 
Sent: Wednesday, 10 July 2013, 14:53
Subject: Re:Re: [time-nuts] How dangerous if Rb lamp broken?
 


Hello Robert:
I am a little confuse how exactly much Rb87 in a bulb? Some people say
that it's couple millgram,  but you tell
me it's half a millgram, which is ture? 
You message is good new to me, it let me relax, but I don’t
understand Bq/gram unit, would you please convert it to mSV unit, I can know
the how many mSV of human is safety by search by internet. I mean in extreme
situration, if all Rb87 of buld sprinkled in my table, how many exposure value
will I accepet in 24 Hour? 
I found some people (other electronics fan) wrote a formula about
Rb87 radioactivity calculation, that is:
1mg Rubidium * 27.835 * 0.27835 * 6.02 *10^23 /
87/4.88/10^10/2/365/24/3600*1=625.
So, decay energy=0.283MeV, about 600 electron per second, Is this calculation
correct?
 
27.835=Percent of Rb87
6.02*10^23 = Avogadro's constant
87= Atomic weight
4.88*10^10== Half time of Rb87 (Year)
2 = Rb87 decay to half
365 = day of year
24 = hour of day
3600 = second of hour
  
  I
am very glad to read many relay of my email, I want say thanks for everyone. As
you said why people be afraid of Rb87 but not other things, I think maybe
because we don’t understand it. Such as, I don’t afraid of RF exposure, because
I know it, I am a HAM and learned many RF exposure knowledge, but of atom and
radioactivity, I have only poor knowledge. 
 
 
Thanks everyone again, this is amazing mail-list. Say sorry for my poor English.
 
Hui


At 2013-07-09 19:40:50,Robert Atkinson robert8...@yahoo.co.uk wrote:
Hi Hui,
Most bulbs use a mix of Rb87 and Rb85 with an activity of around 1500 Bq/gram 
with less than half a millgram in a typical bulb, that's less than a Bq per 
bulb (about 20 picocuries). You will get more ardiation from using low sodium 
salt (potassium chloride) on your food. Potasium is essential for life and Rb 
is chemically similar.
In short don't worry.
Robert G8RPI (also a geiger nut and collector of radioactive material)



From: Hui Zhang ba...@163.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Tuesday, 9 July 2013, 5:07
Subject: [time-nuts] How dangerous if Rb lamp broken?


Dear Group:
I have four compact Rb Stanard, but I am worried about what if my Rb lamp 
broken in accident someday? How dangerous of this situration? Is Rb87 came out 
from Rb lamp will be a disaster? You know I haven't any beta rays detect 
instrument.


Hui
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Re: [time-nuts] How dangerous if Rb lamp broken?

[Robert Atkinson]

Hi Hui,
Most bulbs use a mix of Rb87 and Rb85 with an activity of around 1500 Bq/gram 
with less than half a millgram in a typical bulb, that's less than a Bq per 
bulb (about 20 picocuries). You will get more ardiation from using low sodium 
salt (potassium chloride) on your food. Potasium is essential for life and Rb 
is chemically similar.
In short don't worry.
Robert G8RPI (also a geiger nut and collector of radioactive material)



From: Hui Zhang ba...@163.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Tuesday, 9 July 2013, 5:07
Subject: [time-nuts] How dangerous if Rb lamp broken?


Dear Group:
    I have four compact Rb Stanard, but I am worried about what if my Rb lamp 
broken in accident someday? How dangerous of this situration? Is Rb87 came out 
from Rb lamp will be a disaster? You know I haven't any beta rays detect 
instrument.


Hui
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Re: [time-nuts] How dangerous if Rb lamp broken?

[Robert Atkinson]

Hi
Why are so many people radiophobic? As in ionising radiation. There are far 
more hazardous things in our hobby, electrocution and falling from a height be 
two of the big killers. I defy anyone to come up with a confirmed case of death 
caused by radiation as part of our hobby. Lead, solder flux, mercury, PCB's 
(the chemical in some caps and transformers) and cleaning solvents are all more 
harmful to our health. The use of radioisotopes directly or indirectly saves 
lives every day. Coal fired powerstations release more long life radioactive 
isotopes ro the environment than a nuclear one would ever be permitted to, plus 
a load of heavy metals. 
 
Rant off,
Robert G8RPI.



From: Volker Esper ail...@t-online.de
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Tuesday, 9 July 2013, 11:33
Subject: Re: [time-nuts] How dangerous if Rb lamp broken?



Hi,

Toxicity is not the problem. Radioactivity was my biggest concern, when 
I ordered my first Rb-clock.The manufacturer told me, there's no 
radioactivity, that you have to fear. When the package came I used a 
Geiger tube to calm myself down - there was no measurable activity at all.

If the clock doesn't work anymore, be careful when opening it, the bulb 
could be broken (though impropable). I don't know how the Rubidium will 
react in such a case, but it can react with the air and start to burn 
(but remember, it's a very small amount) and you could get some mg of a 
strong base, which is corrosive/caustic.

To come to the point: You won't be able to wreak havoc with a Rb-lamp...

Volker


Am 09.07.2013 11:40, schrieb Attila Kinali:
 On Tue, 09 Jul 2013 11:24:27 +0200
 Magnus Danielsonmag...@rubidium.dyndns.org  wrote:

    
 On 07/09/2013 06:07 AM, Hui Zhang wrote:
      
 Dear Group:
      I have four compact Rb Stanard, but I am worried about what if my Rb 
lamp broken in accident someday? How dangerous of this situration? Is Rb87 
came out from Rb lamp will be a disaster? You know I haven't any beta rays 
detect instrument.
        
 Considering that you have 48,8 milliard years in half-time, you are
 pretty safe. The problem is rather that it reacts to water and becomes a
 strong base, so you want to keep it dry and well protected. Keeping it
 in a clock chassi is good enough.
      
 IIRC Rb is hygroscopic, ie keeping dry wont help, it will react with
 the air humidity as well. But then, you have only a couple mg of Rb
 in the cell. And the whole thing is enclosed. So you wont get much
 exposure anyways. As for toxidity, AFAIK Rb by itself is not toxic.
 Rb solution is, as Magnus said, a strong base, but you will get very little
 of it and and i am not aware of any toxidity beside being a stron base.
 So don't let it get into your eyes and you will be fine :-)

 For comparison: Natrium hydroxide is sold in tablet form as un-clogging agent.
 It is, for it being a strong base, rated with a high toxidity/danger class,
 (about the same as hydrochloric acid) but is not toxic in it self.
 Handling it is safe, unless you throw a lot of it into water.
 In dry form, the most danger it poses is making soap out of the fat
 in your skin :-)

             Attila Kinali

    


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Re: [time-nuts] HP 5370B dropping mains voltage

[Robert Atkinson]

My reply did not go to the group  due to finger trouble,

Out of phase drops (bucks) the voltage, in phase boosts it. If you want 
variable 
boost/buck use a center tapped variac across the mains and connect the 
primary (rated at half supply voltage, easy in 240V countries) of the fixed 
transformer between the center tap and winding. 
With a 
resistive load as the voltage is reduced, the load current 
reduces so you can do the sums easily. The units I've used it on are 
constant power so the current increases with reducing voltage. However 
it does not matter as we are not generating power. The POWER is the same
 either side of the transformer (ignoring the small transformer losses),
 only the voltage and current change. The transformer is just supplying 
current, it does not matter if it bucks or boosts the voltage. With 
constant load power and transformer, a buck will have have higher 
current at the supply side, a boost will have lower. With a fixed 
resistance load the situation reverses because the power changes with 
the square of the voltage. The maximum load current is set by the 
current rating of the transformer secondary. This is why you can boost 
say 220V to 230V with a 100VA transformer and drive a 2300VA load 
(10Ax10V =100VA, 10Ax230V=2300VA) Some companies actually market power 
savers
 that are just a buck transformer. These things
 only work with resistive loads, or to a small extent, induction motors.
 
For modern equipment with switch mode power supplies they just increase 
the losses.

On insulation, As others have pointed out, a quality transformer will have 
adequate insulation ratings. and there is less differential than normal between 
primary and secondary. The main issue on conventional transformers would be a 
short secondary to frame. Making sure the frame is grounded an input fused 
caters for this. I used Toroids which were tape wrapped. The metal plate they 
were mounted on is grounded.  At least one machine was subject to an individual 
UL inspection (we were a UK company selling world wide) at MIT (no, not the 
audiophools:-) That I attended. The UL inspector had no problem with the boost 
arrangement which was specifically discussed. We did have an intersting 
discussion on shortwave UV light exposure though. Never ground the top of the 
bolt holding down a toroid, It forms a shorted turn.

Robert G8RPI.




 From: Mark C. Stephens ma...@non-stop.com.au
To: Robert Atkinson robert8...@yahoo.co.uk; Discussion of precise time and 
frequency measurement time-nuts@febo.com 
Sent: Saturday, 6 July 2013, 22:39
Subject: RE: [time-nuts] HP 5370B dropping mains voltage
 

How Does that Work Robert?
I mean why out of phase?

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf 
Of Robert Atkinson
Sent: Sunday, 7 July 2013 12:57 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] HP 5370B dropping mains voltage

Hi Marki, 

Dropping the mains voltage is easy. Get a mains to low voltage transformer. 
Connect the primary across the mains and the secondary in series opposition 
(out of phase) with the mains supply. Foar example a 100VA 12V transformer will 
drop your mains to just under 238V with a maximum load of 8A (the current 
rating of the secondary). 


HTH,
Robert G8RPI.




From: Mark C. Stephens ma...@non-stop.com.au
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Saturday, 6 July 2013, 13:25
Subject: Re: [time-nuts] HP 5370B Leds pulsing slowly, buttons selecting 
normally, PB ...


Hi Nigel, 


The only screw type electro can find is 29000uf@10V. it's the same dimensions.
Should I risk the strain on the rectifiers (another 10Kuf is rather a lot)?
Without this timer I am dead in the water so I need to do the right thing 
here...

That's why I posted on the Agilent group too, I need to be sure that I do the 
right thing!

By the way, the failed electro measures 39uf :)

I reckon, the line voltage here is 250v and the equipment is set for 240V, that 
extra 10V on the mains is why I am having so much equipment failure.
Also the Heat sink on the 5370B got so hot I mounted a 5 fan across it to keep 
it at a respectable temperature.

How can I drop the Mains to 240V, I have a boat load of gear that needs to be 
powered concurrently.
(8566A, 8568B, 3585A, 5335A, 5370B, 8901A, etc, powered on together) we are 
starting to talk some serious current there.


-marki


-Original Message-
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Re: [time-nuts] Smithsonian Time/Nav Exhibit

[Robert Atkinson]

For those of us who would have to navigate a long way, there is a on-line 
http://timeandnavigation.si.edu/


Robert G8RPI.




 From: Jim Lux jim...@earthlink.net
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Monday, 1 July 2013, 13:56
Subject: [time-nuts] Smithsonian Time/Nav Exhibit
 

I had a chance to go through the Time and Navigation exhibit at the 
National Air and Space Museum last week. From a time standpoint, 
there's probably not much there that time-nuts don't know already, but 
it's kind of cool to see cleaned up examples of equipment from days gone 
by. (there's an old cesium beam from NIST on display, and a Symmetricom 
cesium turned on and counting, but also a lot of old GPS stuff... lots 
of Rb and Cs for space)

Quite a lot of the exhibit space was devoted to the problem of air 
navigation, which, now that I've seen the exhibit, I can understand what 
challenge it was.  Over centuries, folks had figured out how to navigate 
on ships and on land, but those are inherently slow moving, so you can 
do things like take multiple sextant sights and reduce them.

But planes move fast, so you don't have as much time to do it. It took 
real guts to be the navigator in the little cockpit out front of the 
plane, taking sights with your body out in the wind.  And the poor 
fellow who was sucked out of a plane when taking sights standing on his 
seat and the astrodome blew out.

It was interesting to see how many different schemes were used for 
(mostly radio based) nav in airplanes over a fairly short time. Low 
Frequency DF, A/N Ranges, VOR, LORAN, etc.  I didn't see Omega.

They have an inertial nav unit there from a sub, but not much 
explanation of how inertial nav works.

They talk about the DSN (and actually have a 4 bay rack of the old 
time/frequency  distribution gear on display), but not much discussion 
on exactly how we do navigation for deep space.
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Re: [time-nuts] Oncore UT+ Battery Backup

[Robert Atkinson]

As a side note, I'd use lithiums rather than AA's 

(alkaline) purely because they don't tend to leak corrosive electrolyte all 
over your expensive electronics if (when) you forget to change them. Lithiums 
have a longer shelf life too.



From: mike cook mc235...@gmail.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Thursday, 27 June 2013, 6:28
Subject: Re: [time-nuts] Oncore UT+ Battery Backup



Le 27 juin 2013 à 07:04, Mark C. Stephens a écrit :

 I do believe the UT+ will try to charge the battery while on, so some sort of 
 rechargeable lithium cell is in order. 
 

Yes, you need to connect our battery via Pin1if not using a rechargeable on 
board. 

 -Original Message-
 From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On 
 Behalf Of Bob Stewart
 Sent: Thursday, 27 June 2013 2:11 PM
 To: Time Nuts
 Subject: [time-nuts] Oncore UT+ Battery Backup
 
 My UT+ unit does not have the onboard battery.  In looking at the various 
 manuals, I see that the battery backup voltage is from +2.5 to +5.25V.  So, 
 should I grab a 3V lithium cell and mount off an old motherboard, or should I 
 use a pair of AA batteries in a holder I think I have around here 
 somewhere?  Or is it just whatever comes to hand is fine?  I think the 
 drain is only micro-amps.
 
 Bob - AE6RV
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Re: [time-nuts] Cross border shipping == was: GPS receivers W/timing outputs greater than 1PPS

[Robert Atkinson]

It actually even easier than ever now. Ebay.com do a global postage programme 
http://pages.ebay.co.uk/shipping/globalshipping/buyer-tnc.html#paymentsplit
 
The seller ships it to a US processing center (an item I just won went to 
Kentucky) and they preprocess the customs. I prepaid which saves the £7.5 
collection charge that the UK postoffice levies on the receipient to collect 
the customs fees. OK sometimes an item might miss customs in the UK but you 
can't count on it.
 
Robert G8RPI.



From: Graham planoph...@aei.ca
To: time-nuts@febo.com 
Sent: Thursday, 27 June 2013, 10:46
Subject: [time-nuts] Cross border shipping == was: GPS receivers W/timing 
outputs greater than 1PPS


Often times it is not the perception of additional but rather the 
additional paper work involved in the customs declaration and possibly 
having to go to the post office and wait in line to get the parcel on 
it's way.

To be far, many who list their items as US Only will when I ask, mail 
them also to Canada. I have noticed a trend lately however, were many 
will list the shipping as First Class International flat fee (or 
something like that) which is often 2x or more what it could really be. 
There are many sellers which have it all figured out, provide first rate 
service and reasonable postage charges. The others just haven't quite 
gotten their yet or the amount of their sales going cross border are so 
few in number they have just adopted a way of dealing them which 
provides them the least amount of work.

There is another US seller Dans Small Part who has lots of good items 
at good prices but will not mail cross border. Fortunately there are 
always other options.

cheers, Graham ve3gtc




On 13-06-26 11:04 PM, Mike M wrote:
    Mark C. Stephens
    Wed Jun 26 10:12:53 EDT 2013

     RDR have some fantastic stuff.

     But they won't ship outside of USA.

     I have  tried everything but according to Mark  Cole  the manager,
     The loss  of  time  and  the  additional  risk  of international
     shipping doesn't fit with our business profile

    I don't  know  why  they  think  there  is  additional  risk with
    international shipments. Just send it with a signature required, and
    it has exactly the same risk as any ordinary shipment in the US. But
    a lot of vendors feel the same way.

  

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Re: [time-nuts] +12 Volts 1A (plus a bit) supply?

[Robert Atkinson]

Hi Bob,
As adrian has said, 20V off load is not really excessive. Assuming you are 
using the blue wires and associated bridge rectifier, this was designed to run 
a pair of +5V and -5V regulators, a 7805 and 7905. This means if anything the 
voltage is a little low for 12V output. Try bolting the 7805 to the existing 
TO3 heatsink bracket. The problem is heatsinking not the requlator per se. 
Personally I'd use an LM317 as it's rated for 1.5A and is available in TO3 (but 
the TO220 LM317T will fit too). It has lower drop-out and better protection 
than a 7805 and only needs a couple of resistors to set the voltage. As it's 
not constant 1A and you are not (hopefully) using the isolated 5V supply 
winding (red wires) the transformer should be big enough. Avoid switchers if 
you can, they tend to increase phase noise on the OCXO output.

Robert G8RPI.





 From: Bob Stewart b...@evoria.net
To: Time Nuts time-nuts@febo.com 
Sent: Thursday, 27 June 2013, 20:49
Subject: Re: [time-nuts] +12 Volts 1A (plus a bit) supply?
 

Hi Hal and other responders,

I believe that the OCXO uses an ON-OFF type of regulation.  So, no, it doesn't 
use 1A all the time.  Maybe I should just put an ammeter in the line and see 
what kind of duty cycle it has after it's at temperature.


I tried a 7812 regulator with a small dissipator on it.  It goes into overheat 
mode almost immediately and the output voltage starts quickly doing down.  The 
case does have provisions for a single TO-3 transistor conducting heat to the 
back of the case with no radiating fins.  I had briefly considered using a 
zener and a 2N3055.

I think that instead of worrying this to death, I'm just going to use a brick 
to get it together, and then if something comes up later that I like, I'll put 
that in.  I did like the looks of that PT5102 but it's at end of life, and 1A 
is right at it's limit.  I've given some consideration to seeing whether I can 
pull a few turns off the transformer secondary, as well.


Bob - AE6RV



- Original Message -
 From: Hal Murray hmur...@megapathdsl.net
 To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency 
 measurement time-nuts@febo.com
 Cc: hmur...@megapathdsl.net
 Sent: Thursday, June 27, 2013 2:24 PM
 Subject: Re: [time-nuts] +12 Volts 1A (plus a bit) supply?
 
 
 b...@evoria.net said:
  The transformer gives me about 20 volts DC out.  Dropping 8 volts at 1 amp
  is just a lot of power to void with a resistor.  I'd like to avoid 
 having
  that much waste heat in the unit.
 
 Does it really take 1A after it's warmed up?
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Re: [time-nuts] +12 Volts 1A (plus a bit) supply?

[Robert Atkinson]

Doh,
It's late here, that should have been ...bolting the 7812 to the existing TO3 
heatsink..
Robert.





 From: Robert Atkinson robert8...@yahoo.co.uk
To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency 
measurement time-nuts@febo.com 
Sent: Thursday, 27 June 2013, 22:09
Subject: Re: [time-nuts] +12 Volts 1A (plus a bit) supply?
 

Hi Bob,
As adrian has said, 20V off load is not really excessive. Assuming you are 
using the blue wires and associated bridge rectifier, this was designed to run 
a pair of +5V and -5V regulators, a 7805 and 7905. This means if anything the 
voltage is a little low for 12V output. Try bolting the 7805 to the existing 
TO3 heatsink bracket. The problem is heatsinking not the requlator per se. 
Personally I'd use an LM317 as it's rated for 1.5A and is available in TO3 (but 
the TO220 LM317T will fit too). It has lower drop-out and better protection 
than a 7805 and only needs a couple of resistors to set the voltage. As it's 
not constant 1A and you are not (hopefully) using the isolated 5V supply 
winding (red wires) the transformer should be big enough. Avoid switchers if 
you can, they tend to increase phase noise on the OCXO output.

Robert G8RPI.





From: Bob Stewart b...@evoria.net
To: Time Nuts time-nuts@febo.com 
Sent: Thursday, 27 June 2013, 20:49
Subject: Re: [time-nuts] +12 Volts 1A (plus a bit) supply?


Hi Hal and other responders,

I believe that the OCXO uses an ON-OFF type of regulation.  So, no, it doesn't 
use 1A all the time.  Maybe I should just put an ammeter in the line and see 
what kind of duty cycle it has after it's at temperature.


I tried a 7812 regulator with a small dissipator on it.  It goes into overheat 
mode almost immediately and the output voltage starts quickly doing down.  The 
case does have provisions for a single TO-3 transistor conducting heat to the 
back of the case with no radiating fins.  I had briefly considered using a 
zener and a 2N3055.

I think that instead of worrying this to death, I'm just going to use a brick 
to get it together, and then if something comes up later that I like, I'll put 
that in.  I did like the looks of that PT5102 but it's at end of life, and 1A 
is right at it's limit.  I've given some consideration to seeing whether I can 
pull a few turns off the transformer secondary, as well.


Bob - AE6RV



- Original Message -
 From: Hal Murray hmur...@megapathdsl.net
 To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency 
 measurement time-nuts@febo.com
 Cc: hmur...@megapathdsl.net
 Sent: Thursday, June 27, 2013 2:24 PM
 Subject: Re: [time-nuts] +12 Volts 1A (plus a bit) supply?
 
 
 b...@evoria.net said:
  The transformer gives me about 20 volts DC out.  Dropping 8 volts at 1 amp
  is just a lot of power to void with a resistor.  I'd like to avoid 
 having
  that much waste heat in the unit.
 
 Does it really take 1A after it's warmed up?
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Re: [time-nuts] HP and other equipment failure

[Robert Atkinson]

Hi Perry,
While I agree with everything else you say, you CAN have too much filter 
capacitance. At least where dc rectifier / filter (smoothing) circuits are 
concerned. Increasing C causes increased ripple current and inrush current and 
can overstress rectifiers and transformers. Not actually a problem in most 
cases, but if the rectifier or transformer is already marginal, blindly 
slapping in a much (2x) larger capacitor can cause troubles.

Robert G8RPI.





 From: Perry Sandeen sandee...@yahoo.com
To: time-nuts@febo.com time-nuts@febo.com 
Sent: Friday, 14 June 2013, 5:48
Subject: [time-nuts] HP and other equipment failure
 



All,  
 
There has been an on and off discussion of
equipment failure so I’d thought I’d add my experience.
 
First I’ve been repairing HP equipment since 1976
before many of you were born.
 
I now have over 16 pieces of HP test equipment and
several units now need repair.
 
In my experience, the vast amount of failures are
electrolytic caps with some aggravated by heat.
 
Someone floated the notion of not repairing HP
equipment but cannibalizing it for parts.
 
Please bear with me on my long story.
 
After WWII there were all sorts of surplus stores
selling everything in the mid-fifties.  I
even remember an add in popular Mechanics magazine for a Norden bombsite for
$29.95.  Much of my allowance was spent
on mysterious wonders like a IFF receiver.  Hams reveled in B-29 prop pitch 
motors for rotating beam antennas.  Since it was 28 volt stuff it was far, far
cheaper than commercial equivalents.
 
Then it all gradually disappeared.  Now people want $75 or more for a cruddy
ARC-5 receiver.
 
 Now this is
how it applies to us today.
 
If one peruses the Ebay adds for HP test equipment
one frequently sees a statement like *removed from a place that went out of
business* or something similar.
 
True, the equipment we are buying is 20 years old
or older.  But it is going away never to
return.  I saw an old Ebay invoice from
12 years ago where I won a working HP 3586B for $50.  The shipping cost me 
more!  Now a non-functional unit sells for $400.
 
These prices are only going to continue to rise as
the supply continues to diminish.
 
But this equipment is repairable unlike the
questionable test equipment from China.  Doing preventative maintenance on this 
equipment is not optional if you
want it to continue working.  All electrolytic
caps should be replaced, except for tantalums.  That will be more on a case by 
case business.
 
This is equipment you can repair.  This is not very true for the newer stuff.
 
On the HP 3586B for example, there are a dozen or
so of TVA atoms.  When I do mine I expect
it will then lock below 500 KHz as it is specified.  The HP 5370B needs far 
more cooling than
provided.  I have even given thought to
adding additional resistances to the pass transistor collectors on the outside
by the heat sink.  I found on my two that
the mother board was scorched from overheating by rectifier diodes.  This will 
have to wait until after we have
moved.  I will also add EFC to the 10811 oscillator.
(Why that feature was omitted can be answered by Ric).  
 
There are two long standing truths about
electronic equipment.  One you can’t have
too much filter capacitance.  Two, you
can’t cool too much.  (Please spare me
the  liquid nitrogen or submarine battery
comments.)
 
Regards,

Perrier



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Re: [time-nuts] Cheap 9.8Mhz Sa.22c's

[Robert Atkinson]

Hi Mark,
According to the manual, YES you can select different frequencies. See 
http://www.rdrelectronics.com/skip/feb/SA22c.pdf
The seller doen't ship to the UK, fancy forwarding one for me?

Robert G8RPI.





 From: Mark C. Stephens ma...@non-stop.com.au
To: time-nuts@febo.com time-nuts@febo.com 
Sent: Sunday, 2 June 2013, 18:52
Subject: [time-nuts] Cheap 9.8Mhz Sa.22c's
 

These are 9.8304Mhz, is possible to move them to 10Mhz?

http://www.ebay.com/itm/Symmetricom-SA-22c-9-8304MHz-Precision-Rubidium-Oscillator-5V-and-15V-NICE-/261223397404


-marki


Kind Regards,
Mark Stephens

Mark Clemens Stephens | Customer service engineer | Non-Stop Computer Ltd
* +61 2 9011 8186 | ( +61 428 256 334 | * 
ma...@non-stop.com.aumailto:ma...@non-stop.com.au

Non-Stop Computer PTY LTD
79 Devon St
North Epping
NSW 2121
Australia
Timezone: AEST (UTC +10)

Email: serv...@non-stop.com.aumailto:serv...@non-stop.com.au

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Re: [time-nuts] Cheap 9.8Mhz Sa.22c's

[Robert Atkinson]

Hi Magnus,
According to the datasheet 10MHz is a standard output. The Manual say you can 
change the factory setting using SSIP ( Symmetricom Serial Interface Protocol).
Unless of couse the particular units have been restricted. I don't thnik so as 
both the factory set frequency and 10MHz are coved by the standard unit.

Robert G8RPI.





 From: Magnus Danielson mag...@rubidium.dyndns.org
To: time-nuts@febo.com 
Sent: Sunday, 2 June 2013, 19:06
Subject: Re: [time-nuts] Cheap 9.8Mhz Sa.22c's
 

On 06/02/2013 07:52 PM, Mark C. Stephens wrote:
 These are 9.8304Mhz, is possible to move them to 10Mhz?

 http://www.ebay.com/itm/Symmetricom-SA-22c-9-8304MHz-Precision-Rubidium-Oscillator-5V-and-15V-NICE-/261223397404

I looked at it, and no. They change the core oscillator, and then you 
can alter the divide power of 2 but other than that no luck.

This limits their uses outside the intended usage.

Cheers,
Magnus
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Re: [time-nuts] Good (cheap) PIC chip choice for project?

[Robert Atkinson]

Hi Jason,
Firstly I'm pro PIC so what I say is likely biased ;-)
Look at one of the Microchip PicKit 3 (or even PicKit 2) starter kits. See 
http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGEnodeId=1406dDocName=en538340
The 

DV164131PicKit 3 Debug Express is about $70 and includes a development board, 
in-circuit programmer/debugger and C complier. The programmer will also program 
the earlier series Flash PICs.
Pics are great for little projects were an Arduino is to costly or big. The 
little 8 and 16pin PICs are cheap enough to replace things like 555 timers, 
discrete logic etc. Throw in an onboard comparator, ADC and PWM you have a 
whole host of applications it can cope with. If you are not a C person look at 
ME Labs PicBasicPro, www.melabs.com
Don't go for the high end devices and DSPic unless you really need their 
capabilities.

Robert G8RPI.








 From: Jason Rabel ja...@extremeoverclocking.com
To: time-nuts@febo.com 
Sent: Saturday, 25 May 2013, 20:08
Subject: Re: [time-nuts] Good (cheap) PIC chip choice for project?
 

My reasoning for using a PIC (or similar) is mostly two factors.

First, simplicity... The few things I have in my head that I've wanted to do 
aren't complicated or require special busses. It is
things that you could *probably* do with a whole pile of logic chips, or keep 
it simple with just one PIC. ;)

Second, cost... Spending $30-$40 for a one time project is fine. But say after 
10 or so, the cost savings of a $2 chip vs $30
embedded system starts to add up.

I agree with you that I need to figure out the project details first and what 
I'm trying to integrate with and work backwards. I'm
really glad people are giving me feedback though I didn't know so many 
different options existed (and at so many different price
points). If you don't ask, you will never learn. ;) Both the Arduino and TI 
Launchpad offerings look very intriguing.

I'm on no deadline, so time is not an issue. I just wanted a new challenge and 
this is something I've wanted to dive into for a long
time.

Learning a programming language is not an issue. While I mostly write code in 
PHP, Perl, and shell scripts these days, I used to and
am still somewhat familiar with C/C++. Most other programming languages I've 
used in the past are now probably considered archaic or
defunct. ;)

Looks like I have a lot of reading to do now. Everyone's responses have been 
most helpful!

Jason

 How did you decide to use a PIC and not one of the others such as the
 AVR MSP or whatever?   I don't want to argue for any of the others but
 if you can't list 5 or 6 good reasons to use a PIC and you are not
 able to say why the oters cn't work for you then you've just selected
 something at random without thinking.  SO as a check, see if you can
 list pros and cons.

 You have to decide what you are going to USE the device for first.
 Some are bets for different purposes.  And also how much time you are
 willing to invest in learning.   How much programming experience do
 you have?

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Re: [time-nuts] Follow-up question re: microcontroller families

[Robert Atkinson]

Hi Charles,
I'm biased, but here goes.
With regard to long term support it's hard to beat Microchip products. They 
still supply (or at least a pin equivalent) and support all their controller 
products.
They built their business on support and low cost, reliable development tools. 
You are not forced to re-learn everything when you move to a new family either.

Robert G8RPI.





 From: Charles P. Steinmetz charles_steinm...@lavabit.com
To: TimeNuts time-nuts@febo.com 
Sent: Saturday, 25 May 2013, 21:09
Subject: [time-nuts] Follow-up question re: microcontroller families
 

On another thread, Bob wrote:

If the objective is to complete a very simple, low powered project 
and be done with it, go with the Arduino. If the objective is to 
learn an empire, be very careful about which empire you pick. The 
ARM boys are quickly gobbling up a lot of territory that once was 
populated by a number of competing CPU's. Learning this stuff, and 
getting good at it is a significant investment of time.

I'm starting a new thread because I don't want to hijack the first 
one, which I'm hoping will continue to provide useful information 
about the broad continuum of available devices, from the easy enough 
for a child to assemble and program to the need to learn machine language.

My question here is more pointed: If one is going to learn a new 
system today for timing and other measurement/control projects, which 
empire is likely the best one to choose?

Of course, much depends on what do you want to do with it?  So, 
perhaps, the ultimate answer will be several families, each for a 
class of applications.  But on the other hand, some families may have 
a range of models that fulfill a wide range of applications.  Also, 
my personal approach does not require squeezing each project into the 
most minimal hardware possible -- as long as the added expense isn't 
huge, I'm fine with using more resources than necessary for smaller 
tasks if it means my investment in learning the system (and in 
programming tools) is leveraged more broadly.  Also, my personal 
needs generally do not run to battery or other low-power systems, so 
low power drain is not of great importance to me.

Some of the more systemic (less application-oriented) factors would 
be, which system is more versatile?  Which has the most useful PC 
cards (or development kits) available that do not require the user to 
start with a bare chip?  Which is likely to be around and supported 
longer?  Which is easier to program?  For which is one likely to find 
more programs to study and pirate, more libraries, etc.?  Which is 
easier to outfit with removable memory (USB drives, memory cards, 
etc.)?  Which has better and faster ADCs and DACs?  I'm sure there 
are lots of other factors worth considering, as well.

There may be good resources already available that address these 
issues.  If so, pointers would be appreciated.

Any books people recommend to get a feel for applying and programming 
these devices?

Much appreciated,

Charles







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Re: [time-nuts] Changing FE-5650A frequency?

[Robert Atkinson]

Hi Alec,
Well done and thanks for the credit. I had not looked under the board for the 
crystal or spotted the divider.
One comment. in your blog and ebay description you say that the unit runs on 
15V. The M suffix 5650A is actually designed for a normal aircraft 28V DC 
supply (typical specification range 22-32V). It may run on 15V but it may be 
stressing the power supply circuit and / or under-running the oven. The 
external (28V) supply to the Marconi unit is just filtered, switched and 
connected to the FE-5650A without regulation. It appears that these units have 
options 08, 09, 22 and 25 rolled up into the M military suffix. By the way, 
these units can cost $10,000 or more each for specials see 
http://www.dlis.dla.mil/webflis/pub/pub_search.aspx

Robert G8RPI.





 From: Alexander Wright ale...@gmail.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Saturday, 20 April 2013, 2:33
Subject: Re: [time-nuts] Changing FE-5650A frequency?
 

Success! I've managed to set mine to 10MHz. I've documented this on my blog: 
http://blog.m0tei.co.uk/post/2013/04/20/Mystery-Aircraft-Parts-and-Atomic-Clocks

Thanks to those who offered suggestions.

Regards
Alec
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Re: [time-nuts] Changing FE-5650A frequency?

[Robert Atkinson]

Hi Alec,
Well done and thanks for the credit. I had not looked under the board for the 
crystal or spotted the divider.
One comment. in your blog and ebay description you say that the unit runs on 
15V. The M suffix 5650A is actually designed for a normal aircraft 28V DC 
supply (typical specification range 22-32V). It may run on 15V but it may be 
stressing the power supply circuit and / or under-running the oven. The 
external (28V) supply to the Marconi unit is just filtered, switched and 
connected to the FE-5650A without regulation. It appears that these units have 
options 08, 09, 22 and 25 rolled up into the M military suffix. By the way, 
these units can cost $10,000 or more each for specials see 
http://www.dlis.dla.mil/webflis/pub/pub_search.aspx

Robert G8RPI.





 From: Alexander Wright ale...@gmail.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Saturday, 20 April 2013, 2:33
Subject: Re: [time-nuts] Changing FE-5650A frequency?
 

Success! I've managed to set mine to 10MHz. I've documented this on my blog: 
http://blog.m0tei.co.uk/post/2013/04/20/Mystery-Aircraft-Parts-and-Atomic-Clocks

Thanks to those who offered suggestions.

Regards
Alec
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Re: [time-nuts] Changing FE-5650A frequency?

[Robert Atkinson]

Hi Alec,
I'm an expert searcher ;-). I actually searched for FE-5650 and NSN (NATO Stock 
Number or National Stock Number to Americans) and then plugged the NSN into 
Webflis. There are lots of websites out there that trawl for part numbers and 
NSNs and then try to charge you for information that is freely available 
elsewere. Another good source of data is military specifications. Assist Quick 
search is good but the search engine is a bit fussy http://quicksearch.dla.mil/ 
 try plugging crystal into the title keyword search.

Robert G8RPI.




 From: Alexander Wright ale...@gmail.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Saturday, 20 April 2013, 12:11
Subject: Re: [time-nuts] Changing FE-5650A frequency?
 

On 20/04/13 10:03, Robert Atkinson wrote:
 Hi Alec,
 Well done and thanks for the credit. I had not looked under the board for the 
 crystal or spotted the divider.
 One comment. in your blog and ebay description you say that the unit runs on 
 15V. The M suffix 5650A is actually designed for a normal aircraft 28V DC 
 supply (typical specification range 22-32V). It may run on 15V but it may be 
 stressing the power supply circuit and / or under-running the oven. The 
 external (28V) supply to the Marconi unit is just filtered, switched and 
 connected to the FE-5650A without regulation. It appears that these units 
 have options 08, 09, 22 and 25 rolled up into the M military suffix. By the 
 way, these units can cost $10,000 or more each for specials see 
 http://www.dlis.dla.mil/webflis/pub/pub_search.aspx
 
 Robert G8RPI.
 

Robert,
Good point, well observed!
The power-trends thing inside the package is an adjustable 3A switching 
regulator which seems to be set to nominally ~15.3V (91k setting resistor to 
ground). When i crank up the input voltage, the output voltage of the regulator 
settles to around 15.5v once the input voltage reaches around 19v. According 
the the datasheet the dropout voltage of those regulators is 4V, which means 
these frequency standards should be happy with any input from 19.5-38v.

Where did you find the info about pricing for these? I searched in that form 
for FE-5650A and couldn't find it. I tried searching the whole stable 
oscillator thing's NSN to no avail. I did expect these must have been very 
expensive when they were new though!


On 20/04/13 04:10, WB6BNQ wrote:  Hi Alex,

 Your alternate assumption is the correct one.  Working the formula backwards 
 with the assumptions that the 800 KHz is spot on would then dictate that the 
 DDS out is exactly 12.8 MHz with the final value of the physics package being

 50,255,058.6495

 based upon my HP-35s calculator.

 Many construction and environmental factors affect the actual final frequency 
 of the physics package.  Plus there is some small variance about the center 
 frequency with which signal levels are still strong enough to allow 
 functionality.  The C-field adjustment allow for tweaking within that small 
 variance.  Fortunately, this ability allows for putting the Rb right on the 
 assumed true frequency.

 Provided you have a higher reference source (i.e., Cesium or a well tamed GPS 
 arrangement), the way to properly adjust the Rubidium is to adjust the 
 physics package C-field pot to it minimum frequency point, then set the DDS 
 to the closest point just below the desired frequency and then re-adjust the 
 C-field pot to come up onto the proper frequency.  This is a slow repetitive 
 process requiring time and patience.  The degree of patience will directly 
 correlate with the precision obtained.

 However, if you are not dying to have absolute accuracy, but more interested 
 in the stability provided by the Rb, then do not mess with the C-field pot.  
 If you do not have the means for the calibration, it would, most likely, be 
 safe to assume that the Rb is within 1x10-9 if other means are used to make 
 sure some gross error is not evident.

 I read your blog and, besides the success, it looked like you were having 
 fun.  Good luck,

 BillWB6BNQ


Bill,
I thought as much, thanks for confirming! I'll keep an eye out for any 
callibrated frequency reference I can borrow for 10 minutes to set this with, 
but otherwise I'll leave it as is.


On 20/04/13 09:37, gandal...@aol.com wrote: Hi Alec
 I see your web page and Ebay auction, are you able to supply one still
 complete and unmodified in its original enclosure?
 Regards
 Nigel
 GM8PZR

Nigel,
You mean just the FE-5650A enclosure or the whole stable oscillator thing? Do 
you want to ping me off list?

Regards,
Alec
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Re: [time-nuts] Brooks Shera ASM release

[Robert Atkinson]

Me too,
Didn't say anything before to keep the noise down.
 
Robert G8RPI.



From: Alan Melia alan.me...@btinternet.com
To: time-nuts measurement time-nuts@febo.com 
Sent: Tuesday, 16 April 2013, 0:40
Subject: Re: [time-nuts] Brooks Shera ASM release


Bert  I am grateful for the work you and friends have done.

Is there any way we can add our names to some expression of thanks from
members of the Group to his  widow Karen and her helpers for their work in
making the checked source code for the GPSDO available to us and maybe leave
a  token of remembrance of his worldwide friends, for his family?

Even if it is just a me too replying to this message.

Alan Melia (G3NYK)  Ipswich, UK

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Re: [time-nuts] Connectors

[Robert Atkinson]

Hi Rick,
According to 3M the self amalgamating tape (130) is not UV resistant. They 
recommend covering it with 33+ to keep the light off.  Not sure about the 
ScotchKote. The self amalgamating tape forms an air and watertight seal. It has 
no sulpher so no silver tarnishing. The trick with the 33+ cover layer is to 
minimse the amount of streach. This stops it unravelling. It's just there to 
block the UV. In particular, cut the end of the tape, don't pull it or tear it 
to separate the tape. Here in the UK a common alternative for connector 
protection was Denso tape, a fabric mesh tape filled with a petroleum mastic. 
http://www.denso.net/densotape/  It was developed for protecting idustrial 
pipework. Very effective but messy.
Going back to 3M tapes, I've used 130 and a 3M high temperature fibreglass tape 
to do a roadside repair to a burst car radiator top hose. Used a patch of 130 
(not streached or wrapped) over the hole, double wrap of fibreglass to keep 
that in place. Overlap wrap of 130, more fibreglass, final layer of 130. Lasted 
for a week of 160 miles a day of highway driving until the new hose arrived. I 
was working on a custom machine for 3M in early September 2001 (my return was 
delayed due to the flight ban) and had access to the staff  discount store, I 
came back with a lifetime supply of tape :-)

Robert G8RPI.





 From: Richard (Rick) Karlquist rich...@karlquist.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Saturday, 13 April 2013, 19:56
Subject: Re: [time-nuts] Connectors
 


OK, so we seem to have:

1)  Scotch 130 rubber tape
2)  Scotch 33 electrical tape
3)  Scotchkote

in that order.

So the rubber tape waterproofs
the connection and the scotch kote
protects it from UV, so what does
the electrical tape do?

Or maybe, the electrical tape does
the waterproofing and the rubber tape
just keeps goo off the connector.  But
of course, that can be done with the well
known technique of winding the connector
with electrical tape adhesive side out.

Do we know that the rubber tape is not UV
proof?

Or none of the above.

Can someone in the know clarify this?

Thanks,

Rick
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Re: [time-nuts] Connectors glue lined heatshrink

[Robert Atkinson]

Hi Dave,
Not quite, they do use irradiation crosslinking to make the heatshrink tube, 
but the hotmelt adhesive is a completly separate layer. They do different 
combinations of tube and glue for different applications. Really cool are the 
pre-forms that look like a parallel tube but shrink down into two sises with a 
smooth transition. The mold the final shape and then streach it (hot) into a 
parallel tube. They also do multiple entry versions. Raychem are leaders in 
this. They also do shrink metal parts.

Robert G8RPI.




 From: DaveH i...@blackmountainforge.com
To: n...@verizon.net; 'Discussion of precise time and frequency measurement' 
time-nuts@febo.com 
Sent: Sunday, 14 April 2013, 3:08
Subject: Re: [time-nuts] Connectors
 

Kind of a cool technology -- they bombard the outside of the tube with an
electron beam that cross-links the polymer but leaves the inside untouched.
The outside becomes hard but still shrinks.  The inside just melts into a
goo when heated.

Dave 

 -Original Message-
 From: time-nuts-boun...@febo.com 
 [mailto:time-nuts-boun...@febo.com] On Behalf Of Peter Gottlieb
 Sent: Saturday, April 13, 2013 15:24
 To: time-nuts@febo.com
 Subject: Re: [time-nuts] Connectors
 
 Think of heat shrink with a layer of hot melt glue on the 
 inside. Such stuff is 
 used in most outdoor and especially underground utility 
 wiring.  Shrink the 
 tubing and it melts the glue and the contracting tubing 
 forces the glue into 
 every crevice making a great waterproof splice.
 
 
 On 4/13/2013 5:07 PM, Hal Murray wrote:
  Can someone in the know clarify this?
  I'm not in the know.
 
  Several years ago, I found a short chunk of coax that the 
 cable TV guys had
  left on the ground.  It included a piece of heavy wall 
 shrink tubing.  There
  was a layer of sticky goop between the coax and the shrink tubing.
 
 
 
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Re: [time-nuts] GPS antenna??

[Robert Atkinson]

Hi Rob,
See my earlier post on using repeaters / re-radiators in the UK. Ofcom are 
insitituting a light licencing scheme for GPS / GNSS repeaters. The 
transmit antenna must be inside and the licence fee is £75. No mention that 
I've seen of type approval but they should of course meet CE requirements. 
Connecting an active and passive antenna  back to back (with a bias tee or 
inline amp) is illegal in the UK unless you get a licence from Ofcom first. A 
quick seach on Ofcon GPS repeaters will bring up a bunch of references.
 
Robert G8RPI.





From: Rob Kimberley robkimber...@btinternet.com
To: 'Tom Van Baak' t...@leapsecond.com; 'Discussion of precise time and 
frequency measurement' time-nuts@febo.com 
Sent: Tuesday, 9 April 2013, 12:51
Subject: Re: [time-nuts] GPS antenna??

Unfortunately, (I think this is still valid in the UK), we are not allowed
to use GPS re-radiators. I need to check latest rules  regs.
Rob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Tom Van Baak
Sent: 08 April 2013 22:12
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS antenna??

Alan,

Google for words like GPS re-radiator or GPS repeater. There are also units
on eBay. If not to buy, at least to study examples.

The one I have is made by www.gpssource.com but it seems you could build one
yourself. It's easy to test by looking at your indoor SV count and reception
levels. With patch antennae you don't have to worry about RHCP issues,
right?

/tvb


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Re: [time-nuts] GPS antenna??

[Robert Atkinson]

Hi Alan and Tom,
Note that under the Wireless Telegraphy Act 2006  here in the UK, active GNSS 
repeaters have to be licenced. See 
http://194.33.160.59/radiocomms/ifi/enforcement/gpsrepeaters/
and 
http://stakeholders.ofcom.org.uk/enforcement/spectrum-enforcement/gpsrepeaters/
Even a normal active antenna connected to another antenna would qualify as a 
repeater. Also the transmit antenna must be indoors so your through window 
scheme is out. How about a strip of closed cell foam with a slit for the coax  
that you can trap in the window? This will allow the coax in while keeping the 
drafts out.

Regards,
Robert G8RPI.





 From: Tom Van Baak t...@leapsecond.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Monday, 8 April 2013, 22:12
Subject: Re: [time-nuts] GPS antenna??
 
Alan,

Google for words like GPS re-radiator or GPS repeater. There are also units on 
eBay. If not to buy, at least to study examples.

The one I have is made by www.gpssource.com but it seems you could build one 
yourself. It's easy to test by looking at your indoor SV count and reception 
levels. With patch antennae you don't have to worry about RHCP issues, right?

/tvb

- Original Message - 
From: Alan Melia alan.me...@btinternet.com
To: time-nuts measurement time-nuts@febo.com
Sent: Monday, April 08, 2013 9:59 AM
Subject: [time-nuts] GPS antenna??


 Hi all an interesting problem you may have encountered, I want to use a GPS 
 frequency standard inside a building with no opening windows (opening 
 windows are known as air conditioning in the UK :-))  )
 This is part of a two day amateur microwave conference so we should have the 
 expertise.
 
 I intend to try and pass the signal through a a double glazed glass window 
 unit (hopefully not metalised) using a couple of patch antennas. The outer 
 GPS antenna is active so will need  a 5v supply via an inserter. Inner patch 
 active, outer patch passive to avoid problems of feedback. Main antenna can 
 be shielded from the coupling either physically or with a slab of 
 absorber.
 
 Has anyone tried this? does it work?.any gotchas?
 
 Thanks
 Alan
 G3NYK 


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Re: [time-nuts] Trimble SVeeSix -- was DATUM 9390-52054 Grief again...

[Robert Atkinson]

Hi,
IIRC the early Trimble Placer vehicle tracking GPS receivers used the SVee6 and 
SVee8. I think the Placer 400 used  the SVee6. These units turn up on ebay etc 
at very low cost.

Robert G8RPI.





 From: gandal...@aol.com gandal...@aol.com
To: time-nuts@febo.com 
Sent: Sunday, 7 April 2013, 8:53
Subject: [time-nuts] Trimble SVeeSix -- was DATUM 9390-52054 Grief again...
 
The Trimble TNL 22880-B was indeed the original SV6, or SVeeSix as  Trimble 
chose to call it, I have just confirmed this from a photo I took some  time 
ago, and of which I can supply a copy if required.

The SVeeSix manual from 1992 is here.
http://rapidshare.com/files/446743737/Trimble_SveeSix.pdf

and a much smaller, optimised version, here..
http://rapidshare.com/files/446744995/Trimble_SveeSix_Optimised.pdf

Thanks for these should be directed to Rob Kimberley on the list who  
provided the original printed copy.

This original SVeeSix was approx 4 x 3.5 inches and was  eventually 
replaced by the SVeeEight of similar appearance and  again the same size.
The SVeeSix Plus and SVeeEight Plus were the same modules mounted  in metal 
boxes.
The SVeeEight Plus manual from 2000 is available on the Trimble ftp  site.

I know of at least one application where an SVeeEight PCB module has been  
used as a drop in replacement for an SVeeSix, the Rapco 1804M GPS frequency  
standard, albeit using the opposite serial port, but don't know if this was 
an out of the box drop in or whether the port needed to be configured  
first.

The smaller, 1.8 x 3.3 inches, version of the SVeeSix is  the SVeeSix-CM3 
embedded module, and the 1997 manual for that is also on  the Trimble ftp 
site in the manuals/CM3 folder.

It's possible that an SVeeSix-CM3 could be configured as an SVeeSix  
replacement but I've not investigated this, both the SVeeSix and SVeeEight came 
 
fitted with 1 or 2 standard serial ports on DB9 connectors, the SVeeSix-CM3 
used  an 8 pin header with I/O at TTL levels.

Regards

Nigel
GM8PZR



In a message dated 06/04/2013 23:10:28 GMT Daylight Time, b...@att.net  
writes:

(Note:  additional information about the receiver module has been  added.)

Burt

Gang,

You will remember several months ago I  had some stranges that I 
thought were related to a defective Vectron  oscillator in one of my 
DATUM 9390-52054.  That turned out to be a  the internal switching 
power supply so I replaced it with an external  Cisco unit.  I've done 
this in three units, two are mine and one  belongs to Stu, K6YAZ.

Well, I now have a different grief in one of my  units.  It had been 
cooking along swell with no problem ever since I  replaced the power 
supply.  This morning I notice that one of my  units had the lock and 
tracking lights out.  The display said that  the signal level was low 
and there were no usable satellites.  The 10  MHz output is also about 
20 or more dB low.  I assumed the power  supply is all right because 
the display was working and it said it was  9-E9, not so good, but 
working - sorta.  I swapped antennas and the  good Datum was happy so 
I know the antenna is ok.  when I got inside  I checked the power 
supply rails and they're within .05 Volts of where  they should 
be.  There is 5 Volts on the GPS module and there is 4.96  Volts on 
the antenna Type-N connector (measured with the antenna line  
disconnected.)  Power cycling the DATUM did not resolve the  problem.

Does anyone know if the symptoms above will occur if the 10  MHz 
oscillator is defective?  I can understand it not tracking or not  
locked, but could this cause the receiver to not see or indicate any  
satellites?  Since I only have two of these units on line, I'm very  
reluctant to start swapping modules because I would be without any  
working reference, so I need to keep one up and running.  Both of my  
units are on a UPS, and according to the clocks in the kitchen, the  
bedroom, and the old VCR, we've not had a power interruption.

I do  not recognize the GPS receiver module, but it has the following 
number on  it:  TNL 22880-B.  I have the schematics for the overall 
DATUM  9390-25054, but the GPS module in just a block.  By the way, 
the GPS  block on the DATUM overall schematic is marked, SV6 / 
(TANS).  I  suspect this means something noteworthy.

Any guidance would be  appreciated.

Thanks,

Burt

Burt I. Weiner  Associates
Broadcast Technical Services
Glendale, California   U.S.A.
b...@att.net
www.biwa.cc
K6OQK  

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Re: [time-nuts] Changing FE-5650A frequency?

[Robert Atkinson]

Hi Alex,
These units were used as timing references for secure communication systems 
(Havequick). see ebay item 130832014630. Unfortunatly they are an older design 
with a two chip DDS. The other problem is that the M designation is for 
military and means they have been partially encapsulated with polyurethene 
foam. You can cut it away but it is very easy to damage the PCB. Frequency 
setting is by DIP switches (under the foam) allowing full range of frequency 
selection. However the output filter is narrow so you can't go far from 800kHz. 
Did you buy all seven?

Robert G8RPI.





 From: Alexander Wright ale...@gmail.com
To: time-nuts@febo.com 
Sent: Sunday, 7 April 2013, 0:41
Subject: [time-nuts] Changing FE-5650A frequency?
 
Hi all,
I've recently ripped some FE-5650A's out of some old equipment, but they seem 
to be a custom build, here you can see they have the option just listed as -:
http://cambridge.m0tei.co.uk/files/IMG_20130330_232647.jpg

They seem to be single rail (15v) supply with an 800kHz output. I wonder, does 
anyone know if it's possible to change its frequency? As far as i'm aware this 
model doesn't have serial control.

Thanks,
Alec M0TEI
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Re: [time-nuts] Changing FE-5650A frequency?

[Robert Atkinson]

Hi Herbert,
These units are different to the picture at 
http://www.qsl.net/z/zl1bpu/PROJ/FE5650-2.jpg
They have dip switches and no PIC. The option is covered in one of the manual 
out there but I'm sitting at the wrong computer to dig out the details.

Robert G8RPI.





 From: Herbert Poetzl herb...@13thfloor.at
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Sunday, 7 April 2013, 15:10
Subject: Re: [time-nuts] Changing FE-5650A frequency?
 
On Sun, Apr 07, 2013 at 11:27:23AM +0100, Alexander Wright wrote:
 On 07/04/13 05:01, WB6BNQ wrote:
 Hi Alec,

 You may be in luck.  However, I would need some additional pictures, 
 particularly
 of the connector on the bottom, also some of the inside.


 Bill,

 Thanks for your reply! Here are some photos of the inside: 
 http://m0tei.co.uk/fe5650pics/

 You'll see that it comes with a custom machined plate screwed
 onto the front - this was how it was mounted in the thing i
 pulled it out of. It can be removed but i found it easier to
 take the thing apart with it on. A thermostatic switch used to
 bolt onto it to (presumably) act as a thermal cutout.

The baseplate (2xLM2941, LP2952) basically is the power
supply/regulation, so nothing interesting there.

 You'll also notice that the boards we're probably interested
 in are potted it some sort of white compound - it's hard but
 crumbly - feels like some sort of polymer foam. I've started
 to pick it off a bit but could you just confirm that this is
 actually a sensible thing to do before I go all out scraping 
 it off? 

The purpose of the polymer foam is isolation to keep a 
stable temperature throughout the boards.

http://www.qsl.net/z/zl1bpu/PROJ/FE5650-2.jpg

The top layer in this image is the DDS board, and it is
basically identical to the FE5680A, which means it can
be adjusted in a wide range, but only does digital synthesis
based on the reference frequency.

But let's see what Bill says to the pictures ... :)

best,
Herbert

 Thanks!

 The primary physics package is a stand alone analog Rubidium frequency 
 standard

 that outputs 50.255* MHz frequency.  That signal is used to drive various 
 output
 board configurations, included inside the unit, to provide a customer 
 required
 output frequency.  The more recent revised units (they look the same) use 
 a new
 digital scheme that is much more of a hassle.


 This unit is probably from late 1996/1997 if that helps?

 The one that I and a number of people are familiar with is the 
 5650-option-58
 model whose output was a 1pps.  To get the 1pps the 50.255+ MHz signal was 
 used
 to drive a Direct Digital Synthesizer (DDS) that produced 8.3+ MHz signal 
 that
 was then divided down via normal TTL dividers to produce the 1pps.  The 
 DDS is
 capable of being changed to other frequencies up to about 20 MHz, however, 
 the
 filter following the DDS needs to be changed or bypassed to properly 
 filter the
 new frequency.  Bypassing is the easiest method but would require using an
 external filter to get rid of aliasing and spurs.

 I put together a zip file of various information on FEI-5650-option 58 
 that will
 help you get familiar with the family line.  If you have problems with the 
 link
 let me know.  Also, after you get a successful download let me know so I 
 can
 reduce the FTP storage level, thank you.

 http://pages.suddenlink.net/stevewingate/cryptic1/for alec on 
 5650-option-58.zip

 BillWB6BNQ


 Awesome, looks like there's some great info there! Unfortunately i'm not 
 sure hoe relevant it is to mine since my option doesn't seem to do RS232


 On 07/04/13 04:17, Herbert Poetzl wrote:

 Open it up, take some nice pictures of the circuit boards
 and components and I can probably tell you what might be
 possible (after looking at them :).


 Thanks Herbert! Pictures above^

 As far as i'm aware this model doesn't have serial control.

 best,
 Herbert


 Best regards,
 Alec


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Re: [time-nuts] Trimble SVeeSix -- was DATUM 9390-52054 Grief again...

[Robert Atkinson]

Hi Nigel,
I've had a couple of early Placers and am fairly sure it was a SVee6 but it was 
some time ago. I bought it surplus in the USA in 1998. I may still have one up 
in the attic. I'll go and dig.

Robert G8RPI.





 From: gandal...@aol.com gandal...@aol.com
To: time-nuts@febo.com 
Sent: Sunday, 7 April 2013, 18:37
Subject: Re: [time-nuts] Trimble SVeeSix -- was DATUM 9390-52054 Grief again...
 
Hi Robert,

You need to be careful on this one.

I've never owned a Placer 400, so can't be 100% sure, but whilst  I have 
seen it suggested that it contained an SVeeSix I've have also  seen at least 
one quite emphatic comment, from a not very happy  user, stating that it's 
definitely not an SVeeSix, but that there was a  firmware upgrade available 
for the Placer 400 at one time to  make it SVeeSix compatible, whatever that 
might imply.

What I can confirm is that the version that's more generally available on  
Ebay, the Placer 450, consists of a single board inside the housing that  
integrates a GPS receiver with the control section.
I discovered this the hard way after I bought a couple, and expecting  them 
to contain one of the usual Trimble GPS modules with  a separate PCB for 
the control section, silly me:-)

Quite what the GPS section of that board might be derived from I don't  
know, but it would seem very unlikely that it's going to be a drop in  
replacement for a standard module.

Nigel
GM8PZR



In a message dated 07/04/2013 17:47:40 GMT Daylight Time,  
robert8...@yahoo.co.uk writes:

Hi,
IIRC the early Trimble Placer vehicle tracking GPS receivers  used the 
SVee6 and SVee8. I think the Placer 400 used  the SVee6. These  units turn up 
on 
ebay etc at very low cost.

Robert  G8RPI.





From:  gandal...@aol.com gandal...@aol.com
To: time-nuts@febo.com  
Sent: Sunday, 7 April 2013, 8:53
Subject: [time-nuts] Trimble SVeeSix  -- was DATUM 9390-52054 Grief again...

The Trimble TNL 22880-B was  indeed the original SV6, or SVeeSix as  
Trimble 
chose to call it, I  have just confirmed this from a photo I took some  
time 
ago, and of  which I can supply a copy if required.

The SVeeSix manual from 1992 is  here.
http://rapidshare.com/files/446743737/Trimble_SveeSix.pdf

and  a much smaller, optimised version,  here..
http://rapidshare.com/files/446744995/Trimble_SveeSix_Optimised.pdf

Thanks  for these should be directed to Rob Kimberley on the list who  
provided the original printed copy.

This original SVeeSix was  approx 4 x 3.5 inches and was  eventually 
replaced by the SVeeEight  of similar appearance and  again the same size.
The SVeeSix Plus and  SVeeEight Plus were the same modules mounted  in 
metal 
boxes.
The  SVeeEight Plus manual from 2000 is available on the Trimble ftp   site.

I know of at least one application where an SVeeEight PCB module  has been  
used as a drop in replacement for an SVeeSix, the Rapco  1804M GPS 
frequency  
standard, albeit using the opposite serial port,  but don't know if this 
was 
an out of the box drop in or whether the port  needed to be configured  
first.

The smaller, 1.8 x 3.3 inches,  version of the SVeeSix is  the SVeeSix-CM3 
embedded module, and the  1997 manual for that is also on  the Trimble ftp 
site in the  manuals/CM3 folder.

It's possible that an SVeeSix-CM3 could be  configured as an SVeeSix  
replacement but I've not investigated this,  both the SVeeSix and SVeeEight 
came  
fitted with 1 or 2 standard  serial ports on DB9 connectors, the 
SVeeSix-CM3 
used  an 8 pin header  with I/O at TTL  levels.

Regards

Nigel
GM8PZR



In a message  dated 06/04/2013 23:10:28 GMT Daylight Time, b...@att.net  
writes:

(Note:  additional information about the receiver  module has been  added.)

Burt

Gang,

You will  remember several months ago I  had some stranges that I 
thought were  related to a defective Vectron  oscillator in one of my 
DATUM  9390-52054.  That turned out to be a  the internal switching  
power supply so I replaced it with an external  Cisco unit.   I've done 
this in three units, two are mine and one  belongs to Stu,  K6YAZ.

Well, I now have a different grief in one of my   units.  It had been 
cooking along swell with no problem ever since  I  replaced the power 
supply.  This morning I notice that one of  my  units had the lock and 
tracking lights out.  The display  said that  the signal level was low 
and there were no usable  satellites.  The 10  MHz output is also about 
20 or more dB  low.  I assumed the power  supply is all right because 
the  display was working and it said it was  9-E9, not so good, but  
working - sorta.  I swapped antennas and the  good Datum was  happy so 
I know the antenna is ok.  when I got inside  I checked  the power 
supply rails and they're within .05 Volts of where  they  should 
be.  There is 5 Volts on the GPS module and there is  4.96  Volts on 
the antenna Type-N connector (measured with the  antenna 

Re: [time-nuts] Trimble SVeeSix -- was DATUM 9390-52054 Grief again...

[Robert Atkinson]

Hi  Nigel, 
Had a dig and did not find a placer (yet, I've a lot of stuff up there :-) Did 
find a small Nav-Guide 4700 that seems to be a VHF differential system with a 
Trimble ACE  GPS. Can't find any info on it.


Robert G8RPI.




 From: gandal...@aol.com gandal...@aol.com
To: time-nuts@febo.com 
Sent: Sunday, 7 April 2013, 19:16
Subject: Re: [time-nuts] Trimble SVeeSix -- was DATUM 9390-52054 Grief again...
 
Hi Robert

I'd certainly be interested to hear what you find as I've been after a  
couple of spare SVeeSixes or Eights for some time now, although the Placer 400  
itself doesn't seem to be very common these days either.

I've looked again at the comment stating it's not an SVeeSix and it does  
seem a bit odd as the startup message quoted certainly matches what I see  
from an SVeeSix in a Rapco 1804M, so I'm not sure what caused the  insistence 
that it isn't.

Regards

Nigel
GM8PZR


In a message dated 07/04/2013 18:51:22 GMT Daylight Time,  
robert8...@yahoo.co.uk writes:

Hi  Nigel,
I've had a couple of early Placers and am fairly sure it was a SVee6  but 
it was some time ago. I bought it surplus in the USA in 1998. I may still  
have one up in the attic. I'll go and dig.

Robert  G8RPI.





From:  gandal...@aol.com gandal...@aol.com
To: time-nuts@febo.com  
Sent: Sunday, 7 April 2013, 18:37
Subject: Re: [time-nuts] Trimble  SVeeSix -- was DATUM 9390-52054 Grief 
again...

Hi Robert,

You  need to be careful on this one.

I've never owned a Placer 400, so can't  be 100% sure, but whilst  I have 
seen it suggested that it contained  an SVeeSix I've have also  seen at 
least 
one quite emphatic comment,  from a not very happy  user, stating that it's 
definitely not an  SVeeSix, but that there was a  firmware upgrade 
available 
for the  Placer 400 at one time to  make it SVeeSix compatible, whatever 
that  
might imply.

What I can confirm is that the version that's more  generally available on  
Ebay, the Placer 450, consists of a single  board inside the housing that  
integrates a GPS receiver with the  control section.
I discovered this the hard way after I bought a couple,  and expecting  
them 
to contain one of the usual Trimble GPS modules  with  a separate PCB for 
the control section, silly  me:-)

Quite what the GPS section of that board might be derived from I  don't  
know, but it would seem very unlikely that it's going to be a  drop in  
replacement for a standard  module.

Nigel
GM8PZR



In a message dated 07/04/2013  17:47:40 GMT Daylight Time,  
robert8...@yahoo.co.uk  writes:

Hi,
IIRC the early Trimble Placer vehicle tracking GPS  receivers  used the 
SVee6 and SVee8. I think the Placer 400  used  the SVee6. These  units turn 
up on 
ebay etc at very low  cost.

Robert   G8RPI.





From:   gandal...@aol.com gandal...@aol.com
To: time-nuts@febo.com  
Sent: Sunday, 7 April 2013, 8:53
Subject: [time-nuts] Trimble  SVeeSix  -- was DATUM 9390-52054 Grief 
again...

The Trimble TNL  22880-B was  indeed the original SV6, or SVeeSix as  
Trimble  
chose to call it, I  have just confirmed this from a photo I took  some  
time 
ago, and of  which I can supply a copy if  required.

The SVeeSix manual from 1992 is   here.
http://rapidshare.com/files/446743737/Trimble_SveeSix.pdf

and   a much smaller, optimised version,   here..
http://rapidshare.com/files/446744995/Trimble_SveeSix_Optimised.pdf

Thanks   for these should be directed to Rob Kimberley on the list who  
provided the original printed copy.

This original SVeeSix was   approx 4 x 3.5 inches and was  eventually 
replaced by the  SVeeEight  of similar appearance and  again the same size.
The  SVeeSix Plus and  SVeeEight Plus were the same modules mounted  in  
metal 
boxes.
The  SVeeEight Plus manual from 2000 is available  on the Trimble ftp  
site.

I know of at least one application  where an SVeeEight PCB module  has been 

used as a drop in  replacement for an SVeeSix, the Rapco  1804M GPS 
frequency  
standard, albeit using the opposite serial port,  but don't know if  this 
was 
an out of the box drop in or whether the port  needed  to be configured  
first.

The smaller, 1.8 x 3.3 inches,   version of the SVeeSix is  the SVeeSix-CM3 
embedded module, and  the  1997 manual for that is also on  the Trimble ftp 
site in  the  manuals/CM3 folder.

It's possible that an SVeeSix-CM3 could  be  configured as an SVeeSix  
replacement but I've not  investigated this,  both the SVeeSix and 
SVeeEight 
came  
fitted with 1 or 2 standard  serial ports on DB9 connectors, the  
SVeeSix-CM3 
used  an 8 pin header  with I/O at TTL   levels.

Regards

Nigel
GM8PZR



In a  message  dated 06/04/2013 23:10:28 GMT Daylight Time, b...@att.net  
writes:

(Note:  additional information about the  receiver  module has been  
added.)

Burt

Gang,

You will  remember several months  ago I  had some stranges that I 
thought were  

Re: [time-nuts] OT - DC-10 gyros

[Robert Atkinson]

Hi Bill,
The rated voltage is probably 26V AC rather than 28. I bulit a 3 phase inverter 
for a test rig last year and just used 3 cheap MOSFET power amplifier kits off 
ebay. Changed the feedback C's to limit high frequency response and it was nice 
and stable. When testing put a automotive stop lamp ~20W 12V in series with the 
output, it will protect the output devices and provide a warning if things go 
wrong.
 
Robert G8RPI (CEng MRAeS, still use synchro stuff for the day job!)



From: Bill Ezell w...@quackers.net
To: time-nuts@febo.com 
Sent: Wednesday, 27 March 2013, 22:59
Subject: Re: [time-nuts] OT - DC-10 gyros

I neglected to mention that. The DC resistance of the motor windings is roughly 
200 ohms. I estimate the power draw is  2 watts. Haven't measured the 
inductance.

I probably could just use some FETs and build a simple class-B amp. The sine 
wave doesn't have to be absolutely pure. Frequency stability (at least, in a 
real application) is more important, since the gyro response depends upon the 
rotational speed of the wheel. Not that I'm going to actually use it for 
anything other than just getting it working. :)

On 03/27/2013 6:21 PM, time-nuts-requ...@febo.com wrote:
 For thumbsized gyros, the power-drain is probably very slight.

-- Bill Ezell

They said 'Windows or better'
so I used Linux.

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Re: [time-nuts] OT - DC-10 gyros

[Robert Atkinson]

Hi Bill,
The amp I used was similar to this circuit 
http://www.circuitstoday.com/100w-mosfet-power-amplifier which is a common 
design. Supply is 45V (unregulated rectified and filtered 30V transformer) so 
will drive 26V out OK.
I've also used modules from ILP in the past, sometimes with a step-up 
transformer. To be honest even a square wave chopped up 35V DC would probably 
work OK for these little rate gyros, but they are quieter on a sinewave.
 
Robert G8RPI.



From: Bill Ezell w...@quackers.net
To: time-nuts@febo.com 
Sent: Thursday, 28 March 2013, 11:18
Subject: Re: [time-nuts] OT - DC-10 gyros

It's almost certainly part of the flight stability / autopilot system, as 
suggested privately by another time-nut.
The gyros spin up nicely and run quietly, so sounds like the bearings are fine.

I was using an old Yamaha amplifier I had around for the 400Hz drive. I think 
I'm going to go the audio amp route. The biggest problem I'm having with 
replacing it is that I haven't found a small amp yet that has enough output 
voltage. I'm going to breadboard up something tonight - simple phase-shift 
oscillator driving a pair of FETs in class B configuration with a low-pass 
filter to clean things up. It actually doesn't have to be all that clean. The 
gyros are electromechanical devices after all, they're just little split-phase 
AC motors.

As for what I'm going to do with it, why, the same thing we do with our time 
and frequency related projects - play with it. :) My goal is to get the 
electronics package fully functional. Fortunately, everything is analog using 
transistors you can actually see and quad 741 op-amps in real dip packages, and 
even better, only double-sided pc boards.

On 03/27/2013 11:16 PM, time-nuts-requ...@febo.com wrote:
 Is this part of an HSI (horizontal situation indicator), ADI (attitude
 director indicator), INS (inertial navigation system), or autopilot?  Are
 the bearings dust?
 
 Sounds like fun to play with though.  What do you plan to do with it?

-- Bill Ezell

They said 'Windows or better'
so I used Linux.

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Re: [time-nuts] OT - DC-10 gyros

[Robert Atkinson]

Sorry to reply to my own post, but while looking for the mosfet kit I notice 
that Velleman do a low cost (15 UK pounds, Maplin L85BH ) bipolar 200W (70W 
RMS) amplifier kit that includes the power supply rectifier and filter.  Kit No 
VM100. http://www.vellemanusa.com/products/view/?id=522101 
I've not tried it and am not endorsing it but it looks a good low cost starting 
point.
 
Robert G8RPI.
 



From: Robert Atkinson robert8...@yahoo.co.uk
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Thursday, 28 March 2013, 12:20
Subject: Re: [time-nuts] OT - DC-10 gyros

Hi Bill,
The amp I used was similar to this circuit 
http://www.circuitstoday.com/100w-mosfet-power-amplifier which is a common 
design. Supply is 45V (unregulated rectified and filtered 30V transformer) so 
will drive 26V out OK.
I've also used modules from ILP in the past, sometimes with a step-up 
transformer. To be honest even a square wave chopped up 35V DC would probably 
work OK for these little rate gyros, but they are quieter on a sinewave.
 
Robert G8RPI.



From: Bill Ezell w...@quackers.net
To: time-nuts@febo.com 
Sent: Thursday, 28 March 2013, 11:18
Subject: Re: [time-nuts] OT - DC-10 gyros

It's almost certainly part of the flight stability / autopilot system, as 
suggested privately by another time-nut.
The gyros spin up nicely and run quietly, so sounds like the bearings are fine.

I was using an old Yamaha amplifier I had around for the 400Hz drive. I think 
I'm going to go the audio amp route. The biggest problem I'm having with 
replacing it is that I haven't found a small amp yet that has enough output 
voltage. I'm going to breadboard up something tonight - simple phase-shift 
oscillator driving a pair of FETs in class B configuration with a low-pass 
filter to clean things up. It actually doesn't have to be all that clean. The 
gyros are electromechanical devices after all, they're just little split-phase 
AC motors.

As for what I'm going to do with it, why, the same thing we do with our time 
and frequency related projects - play with it. :) My goal is to get the 
electronics package fully functional. Fortunately, everything is analog using 
transistors you can actually see and quad 741 op-amps in real dip packages, and 
even better, only double-sided pc boards.

On 03/27/2013 11:16 PM, time-nuts-requ...@febo.com wrote:
 Is this part of an HSI (horizontal situation indicator), ADI (attitude
 director indicator), INS (inertial navigation system), or autopilot?  Are
 the bearings dust?
 
 Sounds like fun to play with though.  What do you plan to do with it?

-- Bill Ezell

They said 'Windows or better'
so I used Linux.

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[time-nuts] Rockwell PLGR GPS

[Robert Atkinson]

Hi all,
Not totally timenut, but I have a PLGR for sale and thought I' offer it here 
before putting it on ebay. it's a bit of an odd one, model HNV561A part 
no.822-0766-002. This appears to be the British version of the HMV560C. It is 
not stolen, I obtained it from official UK disposal channels. It works and is 
in fair used condition. Cost is $300 or £200 including postage. Ideal chance to 
get one with the SM without the DoD claiming it's theirs! 
Contact me OFF LIST if inerested.

Robert G8RPI.

Sent from Yahoo! Mail on Android

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Re: [time-nuts] altinex switches

[Robert Atkinson]

Hi Chuck,
some early 75R BNC designs did use a smaller diameter center contact. The 75R 
male can make intermittent contact when used with a worn or top of limit 50R 
female. The 75R female can be damaged for use with the small contact male if 
used with a 50R or large contact 75R male. The do exist, but are pretty rare. A 
lot got changed out as faulty. I've not seen one on any modern (last 20 years) 
equipment.  
 
Robert G8RPI.



From: Chuck Harris cfhar...@erols.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Friday, 22 February 2013, 6:15
Subject: Re: [time-nuts] altinex switches

In general, no, they are not.  The connector pins for modern 75ohm
BNC's are exactly the same part as for modern 50 ohm BNC's.  The BNC
gets the higher impedance inside of the connection area by removing
most of the inner dielectric.

The real problem child, in general, is the female 75 ohm N connector,
vs the male 50 ohm N connector.  In this case, the connector has no
dielectric in the mating area, so in order to keep the impedance
constant, it has to have a smaller diameter center conductor on the
75 ohm variant.  If you attempt to mate a 50 ohm male N connector
with a 75 ohm female N connector, you will split out the female
center socket pin.

Legend has it that there were some variations of the 75 ohm BNC that
don't work with 50 ohm variety I can't speak to whether or not
that is true, only that in my 40 years in the business, I have never
seen one where there was a problem.

-Chuck Harris

paul swed wrote:
 Good point Bob the 75 ohms are smaller in diameter. I use 75 ohm connectors.
 The 50 into a 75 hole spreads the jack.
 Regards
 Paul
 WB8TSL

 On Thu, Feb 21, 2013 at 4:16 PM, Bob Camp li...@rtty.us wrote:

 Hi

 Be careful with the BNC connectors on those switches. 75 ohm BNC's aren't
 the same as 50 ohm connectors. The inner contact is different enough that
 they don't always play well together.

 Bob
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Re: [time-nuts] Low noise power supplies?

[Robert Atkinson]

Hi Bert,
No need to block the DC. These instruments already have DC blocks (and a 
switchable low current DC sink to hold the line from the exchange) because 
the telephone line has a DC voltage of typically 48V on it already.
For comparison I just use 600 ohm termination and dBm, dBmV can be calculated 
or use a look-up table. To compare a batch you can zero the meter on the first 
or known good unit and just read the delta.
 
Robert G8RPI.


From: Burt I. Weiner b...@att.net
To: time-nuts@febo.com 
Sent: Thursday, 31 January 2013, 19:19
Subject: [time-nuts] Low noise power supplies?


Bob,

I have a pair of HP-3551A's*.  I'm very familiar with making transmission lines 
measurements, and it seems that measuring power supply noise would be the same, 
except that you want to block the DC from the input of the instrument.  What 
has your procedure been and what numbers have you come up with?  Since these 
instruments read in dBm0, do you reference from the supply's voltage and then 
convert to mV (difference)?

* One that I picked up off eBay for $75.00 looks new and came with the complete 
manual, and the battery will run it most of the day.

Thanks,

Burt, K6OQK


 Subject: Re: [time-nuts] Low noise power supplies?
 
 A non-standard but repeatable way to measure power supply noise is to use a 
 Transmission Impairment Measuring Set (TIMS) such as the HP3945(6)A or 3551
 (2)A. These were intended for use in pairs to assess analog telephone lines 
 for data use. As well as an AF generator, frequency counter, amplifier, 
 monitor speaker and level meter they will measure broadband noise. Being 
 designed for POTS they will also withstand at least 50V DC at the input while 
 measuring the noise. You can also apply internal filters if required. The 
 last digit designates a North American? (BELL) or European (CCITT) standard 
 unit, but broadband noise is the same. They can be picked up really cheaply 
 now (list was$3000-$5000) and make a nice compact audio test set.
 
 Robert G8RPI.
 
 
 

Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California  U.S.A.
b...@att.net
www.biwa.cc
K6OQK 
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Re: [time-nuts] Low noise power supplies?

[Robert Atkinson]

A non-standard but repeatable way to measure power supply noise is to use a 
Transmission Impairment Measuring Set (TIMS) such as the HP3945(6)A or 3551
(2)A. These were intended for use in pairs to assess analog telephone lines for 
data use. As well as an AF generator, frequency counter, amplifier, monitor 
speaker and level meter they will measure broadband noise. Being designed for 
POTS they will also withstand at least 50V DC at the input while measuring the 
noise. You can also apply internal filters if required. The last digit 
designates a North American  (BELL) or European (CCITT) standard unit, but 
broadband noise is the same. They can be picked up really cheaply now (list 
was$3000-$5000) and make a nice compact audio test set.

Robert G8RPI.





 From: Bob Camp li...@rtty.us
To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com 
Sent: Thursday, 31 January 2013, 18:02
Subject: Re: [time-nuts] Low noise power supplies?
 
Hi

A very common way to check one is to use the HP 3561 off of the old 3048
phase noise test set. With a simple op amp based preamp you can easily get
down below 3 nv / sqrt(Hz). With more exotic amps you can get well below
that. 

Volts over a bandwidth really don't tell the story very well. In the popcorn
noise region, you don't have much choice. Once you get past that PSD is very
much the right way to go. 

For some numbers once you are out of the popcorn / flicker noise region:

1 nV / sqrt(Hz) = about as quiet as it's worth getting ever.
10 nV / sqrt(Hz) = good enough for anything you are likely to be doing
100 nV / sqrt(Hz) = noisy enough to begin to bother you in some cases
1uV / sqrt(Hz) = pretty awful.  

As always, it really depends on what you are doing. A microprocessor will
not be bothered much at all by a relatively noisy supply. 

Bob 

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Burt I. Weiner
Sent: Thursday, January 31, 2013 12:08 PM
To: time-nuts@febo.com
Subject: [time-nuts] Low noise power supplies?

Gang,

I'm following this thread with great interest, but, just for my own 
reference, what is considered low power supply noise?  Can you give 
me some numbers and over what bandwidth?

Thanks,

Burt, K6OQK



         time-nuts@febo.com
Subject: Re: [time-nuts] Low noise power supplies?


Hi

To answer the original question - Power Design makes some pretty quiet
bench
supplies. If you are doing low noise testing, batteries often will let you
get rid of one more ground loop. Even well built power supplies are not as
well line isolated as a battery.

Bob

Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California  U.S.A.
b...@att.net
www.biwa.cc
K6OQK

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Re: [time-nuts] Low noise power supplies?

[Robert Atkinson]

Oops,
 that should be HP4945(6)A not 3945


Robert.



 From: Robert Atkinson robert8...@yahoo.co.uk
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Thursday, 31 January 2013, 18:46
Subject: Re: [time-nuts] Low noise power supplies?
 
A non-standard but repeatable way to measure power supply noise is to use a 
Transmission Impairment Measuring Set (TIMS) such as the HP3945(6)A or 3551
(2)A. These were intended for use in pairs to assess analog telephone lines for 
data use. As well as an AF generator, frequency counter, amplifier, monitor 
speaker and level meter they will measure broadband noise. Being designed for 
POTS they will also withstand at least 50V DC at the input while measuring the 
noise. You can also apply internal filters if required. The last digit 
designates a North American  (BELL) or European (CCITT) standard unit, but 
broadband noise is the same. They can be picked up really cheaply now (list 
was$3000-$5000) and make a nice compact audio test set.

Robert G8RPI.





From: Bob Camp li...@rtty.us
To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com 
Sent: Thursday, 31 January 2013, 18:02
Subject: Re: [time-nuts] Low noise power supplies?

Hi

A very common way to check one is to use the HP 3561 off of the old 3048
phase noise test set. With a simple op amp based preamp you can easily get
down below 3 nv / sqrt(Hz). With more exotic amps you can get well below
that. 

Volts over a bandwidth really don't tell the story very well. In the popcorn
noise region, you don't have much choice. Once you get past that PSD is very
much the right way to go. 

For some numbers once you are out of the popcorn / flicker noise region:

1 nV / sqrt(Hz) = about as quiet as it's worth getting ever.
10 nV / sqrt(Hz) = good enough for anything you are likely to be doing
100 nV / sqrt(Hz) = noisy enough to begin to bother you in some cases
1uV / sqrt(Hz) = pretty awful.  

As always, it really depends on what you are doing. A microprocessor will
not be bothered much at all by a relatively noisy supply. 

Bob 

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Burt I. Weiner
Sent: Thursday, January 31, 2013 12:08 PM
To: time-nuts@febo.com
Subject: [time-nuts] Low noise power supplies?

Gang,

I'm following this thread with great interest, but, just for my own 
reference, what is considered low power supply noise?  Can you give 
me some numbers and over what bandwidth?

Thanks,

Burt, K6OQK



         time-nuts@febo.com
Subject: Re: [time-nuts] Low noise power supplies?


Hi

To answer the original question - Power Design makes some pretty quiet
bench
supplies. If you are doing low noise testing, batteries often will let you
get rid of one more ground loop. Even well built power supplies are not as
well line isolated as a battery.

Bob

Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California  U.S.A.
b...@att.net
www.biwa.cc
K6OQK

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Re: [time-nuts] Thunderbolt Monito - Another option

[Robert Atkinson]

My answer to this problem was to buy a old IPAQ handheld device on ebay ($30 
including a bluetooth GPS mouse) and run the PocketPC version of lady 
heather. You could put the IPAC in its cradle and set it on the bench as a 
remote monitor, but I gutted it and built it into my cased Thunderbolt.

Robert G8RPI





 From: Major L. McGee III maj...@sc.rr.com
To: time-nuts@febo.com 
Sent: Wednesday, 23 January 2013, 16:31
Subject: [time-nuts] Thunderbolt Monitor
 
I have been following this on the list for a while now and was curious if 
anyone is actively working on a open source monitor.  I see the one made by 
Adam VK4GHZ is no longer being sold.  This got me back on track for wanting to 
make one of my own.

I have been using either tbmon or lady heather but always have issues with a 
usb to serial converter when I start the computer.  It will go haywire and 
cause it to freeze and make the mouse malfunction.  Once I disconnect the 
converter (I have tried other makes as well) it works fine.  Usually I can 
reconnect the converter and things will work again.

What I would like to do is make a 2 or 4 line lcd readout to display various 
info.  I really liked VK4GHZ's page type selector knob.  I can see that being 
very useful.  On a youtube video by n6vmo said the thunderbolt used a ASCII Hex 
and needs to be converted by using 64 bit floating point math.

So are any of you currently working on this or have decided to quit and have 
any information to share?


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[time-nuts] FE-5650A with a AD9955 DDS board.

[Robert Atkinson]

Hi,
I just found an FEI FE5650A which has an older DDS board in it. The board has 
an AD9955 DDS chip and 4 8way DIP switches. There is no serial port. It appears 
to be the universal DDS board shown in the manual. The unit is partially 
potted so tracing the circuit is not ideal. Does anyone have info on setting 
the frequency on this DDS board? I've done all the usual searches with no luck.
 
Robert G8RPI.
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Re: [time-nuts] single board PCs

[Robert Atkinson]

Hi Jim,
If space is an issue have a look at PC/104 format boards. These are designed 
for embedded applications and are rugged. Another advantage is that they 
pypically have a long product lifetime. No developing your product, testing it 
and then finding the PC motherboard you used is obsolete or worse has the same 
model number but different hardware.
If you have other electronics in the box they will plug into your board on 0.1 
headers.
 
Rbert G8RPI.



From: Jim Lux jim...@earthlink.net
To: time-nuts@febo.com 
Sent: Monday, 7 January 2013, 4:21
Subject: Re: [time-nuts] single board PCs

On 1/6/13 6:09 PM, Bob Camp wrote:
 Hi
 
 Ummm, er you want to run Matlab and you are likely paying $100 an
 hour to whom ever is waiting on the machine. My *guess* is that a
 micro board of what ever flavor will do an arbitrary Matlab run in
 maybe 30 days.
Yes.
But any of a zillion PC clones will do it fast enough.  Think of all those 
Tek and Agilent boxes with a embedded PC.. what do they have inside?

That same run would take something large about 30
 minutes.

Nahh.. seconds on slow laptop, seconds on a desktop PC. Matlab isn't all that 
slow.

That of course assumes you can even get Matlab to load on
 something small.

It doesn't have to be small.. except physically. That's really what I'm 
looking for. Physically small (mini ITX sort of form factor, or, for that 
matter, laptop formfactor), but able to procured as an OEM sort of widget (e.g. 
I assume Tek and Agilent aren't designing their own mobos to stick in the back 
of an oscilloscope or VNA.. so what ARE they shoving in there)



 
 An Ivy Bridge based PC with multiple cores can be built up for less
 than $800 in a fairly small package. It won't be single board, but it
 will be small. Not the fastest system on the planet, but pretty fast.
 You'll be paying a significant chunk of that for the Windows license.
 The cost of the Matlab license will be well above the cost of the
 entire system (unless you have some sort of crazy deal going).

yep.. but a kilobuck for a Matlab license is just a couple day's time for an 
engineer using it.

Think of that nice Agilent PNA.. clearly it has some sort of small form factor 
PC mobo inside... so what are they using?

 
 Put another way, you'll pay for the more expensive hardware in the
 first week of use - why cheap out?


Precisely.. but I'd just as soon not be in the PC integration business, finding 
boards to plug into a mobo, etc. I was wondering what folks have used (or seen 
used) in this sort of usage model.

 

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Re: [time-nuts] 2.5 Ghz 12 digit counter project

[Robert Atkinson]

Hi,
While it may be a waste of time and money for time nuts, it may be a good 
introduction for others. It may even spawn a few time nuts. Better someone 
build this and learn something than just buy a cheap Chinese counter on ebay. 
I've seen much worse projects published. I do agree that not releasing source 
code is bad practice, especially when a project is code driven.

Robert G8RPI.





 From: ewkehren ewkeh...@aol.com
To: time-nuts@febo.com 
Sent: Friday, 28 December 2012, 13:38
Subject: Re: [time-nuts] 2.5 Ghz 12 digit counter project
 
Lets call it what it is   waste of time and money
Bert Kehren




Sent from Samsung tabletBob Camp li...@rtty.us wrote:Hi

As far as I can see, you would do *much* better with a surplus HP counter (sub 
$200 or even sub $100) and some sort of pre-scaler.

Bob

On Dec 28, 2012, at 2:51 AM, Bruce Griffiths bruce.griffi...@xtra.co.nz wrote:

 Tom Harris wrote:
 Watch out for Silicon Chip designs, they have a habit of not making the
 source code available, which you only find out at the end of the project. I
 suppose that it is to allow the author to make a few extra $$ selling
 programmed micros. They had a nice 3 phase inverter design a year ago that
 had this problem, I wrote to the author promising not to distribute the
 source, I just wanted to read it, but didn't even get the courtesy of an
 answer.
 
 I suspect that this counter is like the inverter, an oldish design that is
 not worth building as you can get the same for half the cost out of China.
 What makes it worthwhile is getting the hardware  the source code, so that
 you can tinker with it.
 
 Actually I had a look at the counter and it looks similar to the 8 digit
 designs using the Intersil 7217 IC from the 80's.
 
 Gripe ends.
 
 On 28 December 2012 06:12, Paul Amaranthp...@auroragrp.com  wrote:
 
   
 Did anyone see the article in the December Silicon Chips magazine about
 building a 12 digit 2.5 GHz counter?  It has an option for a GPS 1pps
 input so you could have some expectation that the last couple of
 digits mean something.  The website only has the article cover page
 in pretty much unreadable type.
 
 --
 Paul Amaranth, GCIH  | Rochester MI, USA
 Aurora Group, Inc.   |   Security, Systems  Software
 p...@auroragrp.com   |   Unix  Windows
 
 
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 I've read the entire set of articles and like most of the designs from this 
 particular designer its largely an unadulterated piece of junk.
 
 Aside from the usual logic design errors I've come to expect from this 
 designer the GPS PPS input is used directly to set the gate time so jitter on 
 this signal directly (several tens of nanaosec or even more if sawtooth error 
 is present better if the PPS is derived from a GPSDO) affects accuracy.
 
 Bruce
 
 
 Bruce
 
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Re: [time-nuts] B-1B bomber time reference

[Robert Atkinson]

Several years ago I bought a very nice 24U EMC screend cabinet at auction. It 
had an Odetics SatSync GPSDo with a rubidium reference, dual redundant power 
supplies, a logic box and an AN/ARC164 UHF transceiverin a 19 rack chassis. It 
was a shipborne havequick timing reference. I still have the SatSync and got 5 
times what I paid for the whole thing for the ARC164 :-)

 
Robert G8RPI.


From: Peter Bell bell.pe...@gmail.com
To: li...@lazygranch.com; Discussion of precise time and frequency measurement 
time-nuts@febo.com 
Sent: Friday, 14 December 2012, 6:24
Subject: Re: [time-nuts] B-1B bomber time reference

One of the very first time related projects I was involved in was for
synchronizing radios - this was when they were retrofitting HAVE QUICK to
the AN/ARC-164 and wanted a cheap, portable source of TOD data - the GPS
was a 2-Channel Magnavox unit (C/A code only) and they also did the
firmware modifications to generate the right data format (STANAG 4246?) -
so basically all that was left was putting them into a box with battery
backup.

Wow, that was more than 20 years ago - I guess I'm getting old...
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Re: [time-nuts] EES RC 1454 100DB MSF/GPS clock

[Robert Atkinson]

Hi Nigel,
Connect did have some recently by this came from another? seller who is from 
the same town. WoodsGroup are also selling them (item 390489973647 ) but at 
excessive prices and without the antenna. The GPS mod seems to replace the PLL 
board and loops the LF signal through. The GPS antenna unit also has an LF 
antenna input. I traced the power (+5V +12V) connections and hooked it up to a 
bench supply without the antenna unit. The supply only has 500mA capability on 
the 12V and went into current limit. Tried a bigger supply and got smoke :-( A 
pot core inductor on the PLL board was cooking. A bit of tracing and it's in 
series with thr 12V supply and antenna connector. The was a short on the MCx to 
BNC lead. It disappaered when I moved it so I'll leave it be for now.
I get a red power LED, green loop lock and 1PPS LEDs but no display. I've got 
the GPS ant on a windowsill so I'll let it seet and see if anything comes up.
 
Robert G8RPI.



From: gandal...@aol.com gandal...@aol.com
To: time-nuts@febo.com 
Sent: Thursday, 29 November 2012, 19:45
Subject: Re: [time-nuts] EES RC 1454  100DB MSF/GPS clock

Hi Robert

For some reason I missed these until you mentioned them but have just taken 
a look and am reminded very much of the similarly modified and boxed EES 
100s  that Connect Distribution were selling around 5 years ago.
Whilst this looks to be a much later unit both EES and Radiocode  clocks do 
seem to have survived for an awful long time without too many  significant 
revisions to their hardware, internal hardware anyway:-)

I've seen a similar connector on one version of the RC060s  but even that 
mainly used conventional D connectors.

From what I remember of the antenna modules on the EES 100s I got the  
impression that the interface processor board extracted the timing information  
from the GPS signal and converted it into an MSF compatible signal to feed 
the  EES 100. I'm sure they didn't frequency convert from L band to 60KHz but 
just  took the GPS data and started from fresh to generate their own MSF  
compatible signal using that data.

I never tried to use one of the modified units straight from MSF but will  
dig one out and try it, I don't think there was very much of a modification 
to  the MSF receiver other than whatever was required to accept another 
60KHz  signal.
I suspect all the hard work was done in the antenna module and the MSF  
unit was just used as decoder and display for the converted  signal.

I may have missed something, nothing unusual there then:-), but it always  
struck me as a rather odd way of accessing and displaying GPS timing data,  
unless initially there was some pressure to find a quick fix utilising 
existing  approved equipment.

Regards

Nigel
GM8PZR










In a message dated 29/11/2012 18:58:47 GMT Standard Time,  
robert8...@yahoo.co.uk writes:

Hi  all,
I recently gave in and bought one of the EES (european electronic  systems) 
RC1454 Radio Clock units that have been on ebay.co.uk for a while.  The one 
I snagged came with a GPS antenna unit. The main unit has a label  saying 
GPS Modified The main box appears to be a MSF receiver but has  no obvious 
power connector, just two rectangular multiway sockets, a 15W D  plug and 
two BNC's. It is a 2U high card frame with 15 PCBS and a LED  display on th 
front. Vintage is late 1990's and both units look like new. The  GPS unit has 
an early Oncore (R1211A) receiver and a PCB with a CPU etc.  Two BNC' marked 
MSF ANT and RX looks like a mod for either MSF or GPS  time. Does anyone 
have any information on these beore I get into major  reverse engineering?

Robert  G8RPI.
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[time-nuts] EES RC 1454 100DB MSF/GPS clock

[Robert Atkinson]

Hi all,
I recently gave in and bought one of the EES (european electronic systems) 
RC1454 Radio Clock units that have been on ebay.co.uk for a while. The one I 
snagged came with a GPS antenna unit. The main unit has a label saying GPS 
Modified The main box appears to be a MSF receiver but has no obvious power 
connector, just two rectangular multiway sockets, a 15W D plug and two BNC's. 
It is a 2U high card frame with 15 PCBS and a LED display on th front. Vintage 
is late 1990's and both units look like new. The GPS unit has an early Oncore 
(R1211A) receiver and a PCB with a CPU etc. Two BNC' marked MSF ANT and RX 
looks like a mod for either MSF or GPS time. Does anyone have any information 
on these beore I get into major reverse engineering?
 
Robert G8RPI.
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