Re: [time-nuts] Question about frequency counter testing

[Glenn Little WB4UIV]

It appears that I replied to the wrong message, please ignore.

Glenn

On 5/27/2018 11:52 AM, Oleg Skydan wrote:

Hi!

From: "Magnus Danielson" 

You build two sums C and D, one is the phase-samples and the other is
phase-samples scaled with their index n in the block. From this you 
can
then using the formulas I provided calculate the least-square phase 
and

frequency, and using the least square frequency measures you can do
PDEV. The up-front processing is thus cheap, and there is meathods to
combine measurement blocks into longer measurement blocks, thus
decimation, using relatively simple linear processing on the block 
sums

C and D, with their respective lengths. The end result is that you can
very cheaply decimate data in HW/FW and then extend the properties to
arbitrary long observation intervals using cheap software 
processing and

create unbiased least square measurements this way. Once the linear
algebra of least square processing has vanished in a puff of logic, it
is fairly simple processing with very little memory requirements at
hand. For multi-tau, you can reach O(N log N) type of processing 
rather

than O(N^2), which is pretty cool.


I had some free time today to study the document you suggested and do
some experiments in matlab - it was very useful reading and 
experiments,

thanks!


Thanks for the kind words!


It looks like the proposed method of decimation can be
efficiently realized on the current HW.


I had some free time yesterday and today, so I decided to test the new 
algorithms on the real hardware (the HW is still an old "ugly 
construction" one, but I hope I will have some time to make normal HW 
- I have already got almost all components I need).


I had to modify the original decimation scheme you propose in the 
paper, so it better fits my HW, also the calculation precision and 
speed should be higher now. The nice side effect - I do not need to 
care about phase unwrapping anymore. I can prepare a short description 
of the modifications and post it here, if it is interesting.


It works like a charm!

The new algorithm (base on C and D sums calculation and decimation) 
uses much less memory (less than 256KB for any gaiting time/sampling 
speed, the old one (direct LR calculation) was very memory hungry - it 
used 4xSampling_Rate bytes/s - 20MB per second of the gate time for 
5MSPS). Now I can fit all data into the internal memory and have a 
single chip digital part of the frequency counter, well, almost single 
chip ;) The timestamping speed has increased and is limited now by the 
bus/bus matrix switch/DMA unit at a bit more then 24MSPS with 
continuous real time data processing. It looks like it is the limit 
for the used chip (I expected a bit higher numbers). The calculation 
speed is also much higher now (approx 23ns per one timestamp, so up to 
43MSPS can be processed in realtime). I plan to stay at 20MSPS rate or 
10MSPS with the double time resolution (1.25ns). It will leave a 
plenty of CPU time for the UI/communication/GPS/statistics stuff.


I will probably throw out the power hungry and expensive SDRAM chip or 
use much smaller one :).


I have some plans to experiment with doubling the one shoot resolution 
down to 1.25ns. I see no much benefits from it, but it can be made 
with just a piece of coax and a couple of resistors, so it is 
interesting to try :).


All the best!
Oleg UR3IQO


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QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
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Re: [time-nuts] Question about frequency counter testing

[Glenn Little WB4UIV]

The MSDS is here:
https://simplegreen.com/data-sheets/

They claim that it is non reactive and chemically stable.
It is for water tolerant surfaces and should be rinsed.
Probably due to the citric acid.

Glenn

On 5/27/2018 11:52 AM, Oleg Skydan wrote:

Hi!

From: "Magnus Danielson" 

You build two sums C and D, one is the phase-samples and the other is
phase-samples scaled with their index n in the block. From this you 
can
then using the formulas I provided calculate the least-square phase 
and

frequency, and using the least square frequency measures you can do
PDEV. The up-front processing is thus cheap, and there is meathods to
combine measurement blocks into longer measurement blocks, thus
decimation, using relatively simple linear processing on the block 
sums

C and D, with their respective lengths. The end result is that you can
very cheaply decimate data in HW/FW and then extend the properties to
arbitrary long observation intervals using cheap software 
processing and

create unbiased least square measurements this way. Once the linear
algebra of least square processing has vanished in a puff of logic, it
is fairly simple processing with very little memory requirements at
hand. For multi-tau, you can reach O(N log N) type of processing 
rather

than O(N^2), which is pretty cool.


I had some free time today to study the document you suggested and do
some experiments in matlab - it was very useful reading and 
experiments,

thanks!


Thanks for the kind words!


It looks like the proposed method of decimation can be
efficiently realized on the current HW.


I had some free time yesterday and today, so I decided to test the new 
algorithms on the real hardware (the HW is still an old "ugly 
construction" one, but I hope I will have some time to make normal HW 
- I have already got almost all components I need).


I had to modify the original decimation scheme you propose in the 
paper, so it better fits my HW, also the calculation precision and 
speed should be higher now. The nice side effect - I do not need to 
care about phase unwrapping anymore. I can prepare a short description 
of the modifications and post it here, if it is interesting.


It works like a charm!

The new algorithm (base on C and D sums calculation and decimation) 
uses much less memory (less than 256KB for any gaiting time/sampling 
speed, the old one (direct LR calculation) was very memory hungry - it 
used 4xSampling_Rate bytes/s - 20MB per second of the gate time for 
5MSPS). Now I can fit all data into the internal memory and have a 
single chip digital part of the frequency counter, well, almost single 
chip ;) The timestamping speed has increased and is limited now by the 
bus/bus matrix switch/DMA unit at a bit more then 24MSPS with 
continuous real time data processing. It looks like it is the limit 
for the used chip (I expected a bit higher numbers). The calculation 
speed is also much higher now (approx 23ns per one timestamp, so up to 
43MSPS can be processed in realtime). I plan to stay at 20MSPS rate or 
10MSPS with the double time resolution (1.25ns). It will leave a 
plenty of CPU time for the UI/communication/GPS/statistics stuff.


I will probably throw out the power hungry and expensive SDRAM chip or 
use much smaller one :).


I have some plans to experiment with doubling the one shoot resolution 
down to 1.25ns. I see no much benefits from it, but it can be made 
with just a piece of coax and a couple of resistors, so it is 
interesting to try :).


All the best!
Oleg UR3IQO


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QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
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Re: [time-nuts] Weird Stuff WareHouse shutting down

[Glenn Little WB4UIV]

The USB stuff has no front end and stability and calibration is highly 
questionable..
How can you discriminate between mixes within the USB device and the 
signal of interest?

I will take my 141T or my 8566 over USB every time.
Rather lug a little weight around and know what I am seeing on the 
display is what is really out there.
There is a reason that usable SAs have weight to them and USB devices do 
not.


Glenn


On 4/8/2018 6:58 PM, Andy ZL3AG via time-nuts wrote:

On 9/04/2018, at 3:52 AM, jimlux wrote:


Test equipment tends to be aged - Unless you have a particular need for a HP 
600 series microwave signal generator, there are probably better sources 
available much cheaper that use more modern components. In this day and age, I 
don't think people should suffer through 141T spectrum analyzers or even a 
8568- Spend your money an a nice USB unit instead.


Blasphemy!


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Glenn LittleARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
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Re: [time-nuts] TV Signals as a frequency reference

[Glenn Little WB4UIV]

I was a chief engineer for a TV station during the transition to digital.
I am now a transmitter supervisor for two digital TV transmitters.

None of the stations in my area have a frequency standard.
Time in injected into the digital stream usually from a pc clock.
This pc may or may not be allowed to communicate with a ntp server.
The way you determine the frequency of a digital tv station is to look 
at the spectrum and determine the frequency of the pilot which is the 
highest peak in the spectrum.


There is no requirement for us to inject time of any prescribed accuracy 
into the digital stream.


The tv transmitter may or may not be locked to a gps derived source.
The exciter is usually synthesized with the reference as a crystal that 
may or may not be stabilized by any accurate means.
At a previous UHF station, the frequency was controlled by a TO-5 cased 
crystal in a very small oven.


I would not rely on a signal from a tv station as a time or frequency 
standard unless you know how their timing and frequency is derived.


73
Glenn
WB4UIV



On 3/31/2018 9:38 AM, Bob kb8tq wrote:

Hi

My comments really were a bit brief…. indeed there *are* clocks in the modern
signals. Those clocks come over as part of the signal you get. The must be a
way to build something that would get at those clocks.

You still have the same basic issue as with the “old” signals. Does it go 
through
a satellite link? Does it come straight from a Cs based studio? Does it get 
regenerated
against an OCXO or a TCXO? All of that will make it a good reference “some of
the time”. Working out when that is …. good luck.

You probably would do better to build a gizmo to pull timing off you local cell 
towers.
The hardware to do it is relatively well documented. As long as you are careful 
about
which system you use, the timing should be GPS based ….

Ok, so the issue is an alternative to GPS? Well one of the “likely sources” for
a modern TV broadcast setup would be a GPSDO. The same thing for the modern
digital FM broadcast setups. I have good reason to make this claim ….. :)

Bob


On Mar 31, 2018, at 1:43 AM, Hal Murray  wrote:


As noted earlier, color burst references were a big deal a long time ago.

Thanks.  I was fishing for something modern, maybe a bit clock out of the
digital receiver.

I'm assuming that the digital stream is locked to the carrier.  That may not
be correct.


--
These are my opinions.  I hate spam.




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--
---
Glenn LittleARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
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Re: [time-nuts] Symmetricom S200 PSU

[Glenn Little WB4UIV]

Opto-isolators degrade with time.
The "optically clear" material between the emitter and detector will 
start turning opaque with time.

At least this is what my boss told me years ago.
We has a product that used opto-isolators to isolate our circuits from 
phone lines.

After a few years of use, the boards started failing.
When we measured the transfer characteristics of the opto-isolators, we 
found them to be degraded.

Replaced the opto-isolators and the boards functioned again.
Could have been a design error on our boards, who knows.

Opto-isolators ate cheap.

Replace it and see what happens.

Any and all parts are suspect, some more than others.
To me, it would be physically damaged parts, electrolytic capacitors, 
opto-isolators, solid state devices then other parts.


73
Glenn



On 10/1/2017 12:26 PM, Lists via time-nuts wrote:

Thanks for the reply Clint. I spent some time on it today with no luck, I do 
have some more info though…

The primary seems ok, there is a steady 329volts DC across the big cap after 
the rectifier diodes.

When you power it up under its normal load you can hear the transformer 
whistle, which you could not hear when it was working, also measuring the DC 
outputs gives almost exactly half the expected output, i.e.

+2.54v
+6.02v
-5.88v

Unfortunately I only have a multimeter and no ‘scope so any further fault 
finding is difficult. I guess the next step is to replace the mos fet that 
drives the transformer, or I guess it could be the feedback loop, which looks 
like an opto-isolator, doubt that the isolator itself would die, but there’s a 
PNP transistor driving it…

If anyone has any other ideas I’m listening !

Thanks,
Chris



On 18 Sep 2017, at 20:21, Clint Jay  wrote:

Hi Chris, if it's not blowing fuses and you're sure you've got all the 
capacitors ( low value ones in the primary specifically) then check all the 
high value resistors on the primary and continuity from reservoir capacitor to 
switching transistor.

The average SMPSU usually doesn't deviate wildly from the application notes of 
the switching controller so if there's no specific schematic that might be a 
lifeline.



On 18 Sep 2017 20:08, "Lists via time-nuts" > wrote:
Hello Fellow Time Nuts,

Does anyone know where I can get either a circuit diagram or a replacement PSU 
for a symmetricon S200 NTP server?

I’ve fixed the original one twice before by replacing all the electrolytic 
caps, this time it’s popped something more critical and refuses to come back to 
life.

So I either need a new PSU or a circuit diagram so I can fault find on the 
original.

I’m in the UK.

Thanks,
Chris


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--
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Glenn Little ETCS(SS) USN Ret, ARRL Technical Specialist,  SBE ARRL TAPR
Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI, FRA, NRA LM  QCWA  LM 28417
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[time-nuts] Bulova crystal oscillator

[Glenn Little WB4UIV]

I have a Bulova crystal oscillator, part number 1505869-1K, model number 
AMO31HP-V-1, NSN 6N5840-797-7659.
The NSN tells me it is a little old and that it was a turn-in, probably 
repairable at some higher level.

The frequency is marked 100.00 KHz.
The oscillator voltage is 30 V DC and the oven voltage is 115 VAC.
It has an octal plug on the bottom with the pins marked:
1 - oven indicator
2 - A.F.C.
3 - heater power
4 - +30 VDC
5 - case ground
6 - ground
7 - heater return
8 - 100 KC output.

With the nameplate listing the frequency in KHz and the case listing the 
frequency in Kc and the older NSN, it appears that this oscillator was 
made for a longer period of time.


The top has two adjustments, both with a screw cover.
One is freq adj and the other is output adj.

Does anyone have any data on this oscillator?
What would I expect the accuracy to be?
The printed frequency implies, to me, that the accuracy is in the realm 
of 0.001 Hertz at 100 KHz.

Did I miss something here?
The top also shows this to be a "Generator Reference Signal".

Any insite appreciated.

73
Glenn
WB4UIV

--
---
Glenn LittleARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
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Re: [time-nuts] GPS Antenna Feed Line Decision

[Glenn Little WB4UIV]

I work with a broadcast station.
We just had a HD FM radio transmitter upgrade done.
In the upgrade package from GatesAir was a GPS antenna with a F fitting.
The provided feedline was RG-223 with a TNC on one end and a SMA on the 
other.

Also provided was a TNC to F adapter.
The new exciter has a GPS receiver installed to provide 1 PPS to the 
exciter.
There was also another piece of equipment that required 1 PPS and they 
provided an antenna and no feedline with that one.

Either piece would output 1 PPS, so the second antenna was not needed.

So you wonder what the "professionals" had in mind with the adapters.
Low bidder for the antenna??

73
Glenn
WB4UIV

On 9/3/2017 10:09 AM, Wes wrote:

On 9/2/2017 4:48 PM, Clay Autery wrote:

Thanks for the response...

Not sure why you and the other guy both recommended RG-6 75-Ohm cable
and F-connectors, when the nominal impedance of literally everything
else in the system is 50 Ohm, including the antenna and the HP GPS
Distribution Amp  And then adding N to F adapters?
As "the other guy" (I think) let me say that the impedance mismatch is 
immaterial and in my case I have one GPSDO with an SMA connector and 
another with a BNC and an antenna with an SMA.  So I "adapt" no matter 
what I do.  Because I understand the cascaded noise figure equations, 
I know that I don't need an active distribution amplifier to feed just 
these two devices, so a $5.00 "F" connector splitter is adequate. 
(https://www.markertek.com/product/201-232/2-way-2-4ghz-90db-satellite-splitter-dc-power-passing-to-one-port)

Doesn't make any sense unless one has $$ as a top priority, already has
a spool of RG-6 quad shield, etc...  but I specifically stated that $$
is not a top priority  Not really even in the top 5 or 10...

Then by all means you should use L-band waveguide. :-)

Wes

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QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
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Re: [time-nuts] Austron/ Systrom Donner 8181 Time Code Reader

[Glenn Little WB4UIV]

Here is a calculator to determine the resistor value.



You will probably have to provide an external supply, at the zener 
voltage, to know what the current draw is for the calculator.


You might find that the original resistor value was too low or the zener 
wattage was too low for the circuit draw.


You might also find a leaky filter capacitor down stream causing the 
current to be too high.
There may be a leaky filter capacitor up stream causing the zener to 
draw too much current as the peak voltage may have exceeded the original 
calculations.


73
Glenn


On 4/23/2017 2:31 PM, Dave Wood wrote:

Bill, actually what happened is the zener diode that the resistor fed
shorted and that's the reason it burned up.  I have two units with this
issue and I cannot read the resistor value since it burned up.  What I
would love to know is what the original value of the dropping resistor
was?  73  Dave

On Sat, Apr 22, 2017 at 11:39 PM, Bill Hawkins  wrote:


There is usually a power dissipation reason why a resistor becomes
toast, and the reason is frequently a shorted bypass cap or a shorted
device.

Have you measured the resistance to ground of the end of the resistor
opposite the power supply?

Sometimes inputs get high voltages and short the amplifying device.

Sometimes that is reason the units were for sale.

Hope I'm wrong.

Bill Hawkins


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Dave
Wood
Sent: Saturday, April 22, 2017 8:43 PM

Anyone on the list own the above Time Code Readesr.  I have one of each,
they are identical with the same issue.  I need to identify the correct
value of a resistor in the power supply that provides 27 volts to the
input amp.  They are both toast in my units and I do not have a manual.
Thanks in advance!  Dave ___

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QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
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Re: [time-nuts] HP 5275A

[Glenn Little WB4UIV]

A 2N1038 is in a TO-5 or TO-11 package.
A 2N1038-2 is a modified or selected part.
Is this transistor pressed into a hexagonal bushing that is about 1/2 " 
long with a 10-32 threaded stud for mounting?

If so the bushing/heatsink is part of the transistor.
A google search for 2N1038 will show this this transistor and a similar 
one with the integral heatsink.


Glenn


On 11/6/2016 5:46 PM, djl wrote:

Just homemade opto-isolators. Used in choppers, too. The transistor was
indeed bonded to the heatsink.  Just replace the whole thing with a
3-legged regulator? or simply a modern PNP t0-220 with a little heat
sink on it.
73, Don


On 2016-11-06 15:15, paul swed wrote:

Don't know what to say on the transistor. It may have been actually made
that way. They did lots of things back then. Yes familiar with the bcd
decoder its used in the 5245 class counters also. I think someone was
doing
some funny stuff at lunch time to come up with that. It was the 60's
after
all.
How about some pix of a 9815 calc. That would be pretty neat.
On really old stuff if you can't find the part needed its pretty easy to
replace the whole function with modern answers. I know it sort of breaks
the original mode but for me at least its a case of getting it going.
Regards
Paul
WB8TSL

On Sun, Nov 6, 2016 at 1:59 PM, Adrian Godwin 
wrote:


Slightly off-topic, as this is a general repair question. But it's a
TIC.

I'm repairing a 5275A timer (all-discreet count logic to 100MHz, neon
bulb
display, a most amazing bcd to decimal decoder made from neons and LDRs,
1-2-2-4 decade counters ..) and the current problem is a 2n1038-2
germanium
T05 transistor in the power supply.

It's mounted in an aluminium bush which is then isolated from the
chassis.
I don't think the bush is also a collet but I can't see how to remove
the
transistor. It resists ungentle pushing .. should I push it with a
hammer ?
Or is there a kinder way ?

(I'm hoping to eventually put this into a system with a 101A
oscillator and
a 9815A calculator to measure the ADEV of a Boule electric pendulum
clock).
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Glenn LittleARRL Technical Specialist   QCWA  LM 28417
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QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
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Re: [time-nuts] ke5fx.com - something's up

[Glenn Little WB4UIV]

Try the wayback machine: 



This is an archive of many websites.

73
Glenn
WB4UIV

On 9/10/2016 6:48 PM, Nick Sayer via time-nuts wrote:

I tried to look for Lady Heather docs today, but it appears like the ke5fx 
domain is… funky.

The name servers are NS1.PENDINGRENEWALDELETION.COM and there are other 
indications that maybe the domain lapsed…?
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--
---
Glenn LittleARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
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Re: [time-nuts] GPS? Antenna

[Glenn Little WB4UIV]

Thanks for all of the help.
I contacted Huber Suhner and now have the data sheet and radiation 
patterns for this antenna.


73
Glenn
WB4UIV



On 9/6/2016 4:25 AM, Szeker K. wrote:

Yes its H-S model, and it must be a GPS antenna...
http://www.cafr.ebay.ca/itm/Ericsson-KRE-1012082-1-GPS-Antenna-26dBi-For-HUBER-SUHNER-84097323-/182012930579?hash=item2a60d0ea13:g:MAMAAOSwZd1Vdn6-
Regards
Karl

2016-09-06 5:12 GMT+02:00 Chris Waldrup <kd4...@gmail.com>:


It's a Huber Suhner.

Chris


On Sep 5, 2016, at 21:26, Glenn Little WB4UIV <

glennmaill...@bellsouth.net> wrote:


Pete,

I do not know if I can send a picture to the mailing list.

I am sending this to you and the list.

The antenna is 4 inches from tip of cone to bottom of type-N connector.
It is 2 5/8" in diameter.

Thanks
Glenn




On 9/5/2016 8:25 PM, Pete Lancashire wrote:
Nemko is the Norwegian "UL", my guess is the numbers are the
test/certification numbers. A picture would help

-pete

On Mon, Sep 5, 2016 at 5:14 PM, Glenn Little WB4UIV
<glennmaill...@bellsouth.net <mailto:glennmaill...@bellsouth.net>>

wrote:


   At the last hamfest that I attended, I bought an antenna that looks
   like a GPS antenna.
   The price was right.
   This is a Nemko Article number: 84097323, Type number 1315.17.0018.
   It has a manufacturing date of 09/2012.
   Can anyone tell me if this is in fact a GPS antenna and what voltage
   wold be required.
   I would suspect that it would be either 5VDC or 3.3 VDC based on the
   date.
   Any help appreciated.

   Thanks
   73
   Glenn
   WB4UIV

   --
   

---

   Glenn LittleARRL Technical Specialist   QCWA  LM

28417

   Amateur Callsign:  WB4UIVwb4...@arrl.net
   <mailto:wb4...@arrl.net>AMSAT LM 2178
   QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
   "It is not the class of license that the Amateur holds but the class
   of the Amateur that holds the license"
   

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Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
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QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
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[time-nuts] Datum TS2100 GPS issues

[Glenn Little WB4UIV]

Is there a fix for the rollover problem for this instrument short of 
replacing the receiver? In searching the archives, this is the only 
solution that I see.


Thanks
73
Glenn
WB4UIV
--
---
Glenn LittleARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
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[time-nuts] GPS? Antenna

[Glenn Little WB4UIV]

At the last hamfest that I attended, I bought an antenna that looks like 
a GPS antenna.

The price was right.
This is a Nemko Article number: 84097323, Type number 1315.17.0018.
It has a manufacturing date of 09/2012.
Can anyone tell me if this is in fact a GPS antenna and what voltage 
wold be required.

I would suspect that it would be either 5VDC or 3.3 VDC based on the date.
Any help appreciated.

Thanks
73
Glenn
WB4UIV

--
---
Glenn LittleARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
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Re: [time-nuts] GPS antenna selection - lightning

[Glenn Little WB4UIV]

The latest that I can find is 1987.
If you understand the theory and practice, you do not have to update 
your work often.
It is the works that are updated every few months that you have to worry 
about. The did not get it right the first time.


This is still an active military document.

73
Glenn
WB4UIV

On 8/6/2016 1:13 PM, Chris Albertson wrote:

If you are looking for info in lightening.  University of Florida has a
huge collection and also points to many other places on the web.   They
actually do testing there, lightening occurs so reliably almost every day
in summer.  Their test tower gets many hits
http://www.lightning.ece.ufl.edu

But really, for practical purposes Ben Franklin got it pretty close to
right.  Give the lightening a good low impedance path to ground.

On Sat, Aug 6, 2016 at 8:00 AM, Clay Autery <caut...@montac.com> wrote:


Is the 1987 version the latest issue available for free?

__
Clay Autery, KY5G
MONTAC Enterprises
(318) 518-1389

On 8/6/2016 8:46 AM, Glenn Little WB4UIV wrote:

Cone of protection is addressed.
Volume 1 is theory, volume 2 is application.
The military requires 1/0 cable exterior to the building, commercial
practice is #2AWG.
Ground rod spacing is address.

Overall a very good reference based on practical experience and backed
with theory.

73
Glenn
WB4UIV


On 8/6/2016 1:19 AM, Bill Hawkins wrote:

Hi Glenn,

Your advice is excellent.

Seems like every time we have a lightning discussion there is no
distinction between an EMP and a direct hit.

I started work in 1960 at a blasting cap plant in upstate New York. The
powder magazines were protected by tall masts according to the "cone of
protection" theory. The angle of the cone varied between 45 and 60
degrees. The earth ground resistance of the mast was measured by a
hand-cranked device that looked like a megger but read earth resistance
to less than a tenth of an ohm. Had the lightning but never lost a
magazine.

You say MIL-HDBK-419 covers EMP. Does it also cover cone of protection
for direct hits?

I was fascinated by the idea that a simple capacitor discharge into an
inductor could be greatly enhanced by reducing the diameter of the
inductor with a conventional explosive, described in one of Stephen
Coonts' books, if my failing memory recalls correctly. And so I learned
what I could about EMP. Never built anything, just interesting behavior.

Best regards,
Bill Hawkins


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Glenn
Little WB4UIV
Sent: Friday, August 05, 2016 9:47 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts]GPS antenna selection - lightning

A very good reference for EMP protection is MIL-HDBK-419.
This is downloadable for a number of web sources.
It is about 600 pages and is in two volumes.
This discusses a number of different sources of EMP such as nuclear and
lightning.
A lot is for protection of military industrial complexes, but, there is
a lot that pertains to us.

I worked for a military complex that assembled nuclear missiles.
The site was built to this handbook specs.
We had no EMP related damage at the site.

Number one rule, bond all grounds together. If something on your
property takes a hit, you want everything on your property to elevate to
the same level and the same rate.
If you have multiple, non bonded grounds, there is a different reference
for each ground. This is a major source for disaster.

I spent seven years in lightning mitigation. I was told by professionals
that I was wrong. The third time that their tower was struck, destroying
all of the lights and attached equipment, they followed my
recommendations. That was ten years ago. The three hits were within four
months of each other. The site has been free of destructive hits since
then.

73
Glenn
WB4UIV








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--
---
Glenn LittleARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
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Re: [time-nuts] GPS antenna selection - lightning

[Glenn Little WB4UIV]

Cone of protection is addressed.
Volume 1 is theory, volume 2 is application.
The military requires 1/0 cable exterior to the building, commercial 
practice is #2AWG.

Ground rod spacing is address.

Overall a very good reference based on practical experience and backed 
with theory.


73
Glenn
WB4UIV


On 8/6/2016 1:19 AM, Bill Hawkins wrote:

Hi Glenn,

Your advice is excellent.

Seems like every time we have a lightning discussion there is no
distinction between an EMP and a direct hit.

I started work in 1960 at a blasting cap plant in upstate New York. The
powder magazines were protected by tall masts according to the "cone of
protection" theory. The angle of the cone varied between 45 and 60
degrees. The earth ground resistance of the mast was measured by a
hand-cranked device that looked like a megger but read earth resistance
to less than a tenth of an ohm. Had the lightning but never lost a
magazine.

You say MIL-HDBK-419 covers EMP. Does it also cover cone of protection
for direct hits?

I was fascinated by the idea that a simple capacitor discharge into an
inductor could be greatly enhanced by reducing the diameter of the
inductor with a conventional explosive, described in one of Stephen
Coonts' books, if my failing memory recalls correctly. And so I learned
what I could about EMP. Never built anything, just interesting behavior.

Best regards,
Bill Hawkins


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Glenn
Little WB4UIV
Sent: Friday, August 05, 2016 9:47 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts]GPS antenna selection - lightning

A very good reference for EMP protection is MIL-HDBK-419.
This is downloadable for a number of web sources.
It is about 600 pages and is in two volumes.
This discusses a number of different sources of EMP such as nuclear and
lightning.
A lot is for protection of military industrial complexes, but, there is
a lot that pertains to us.

I worked for a military complex that assembled nuclear missiles.
The site was built to this handbook specs.
We had no EMP related damage at the site.

Number one rule, bond all grounds together. If something on your
property takes a hit, you want everything on your property to elevate to
the same level and the same rate.
If you have multiple, non bonded grounds, there is a different reference
for each ground. This is a major source for disaster.

I spent seven years in lightning mitigation. I was told by professionals
that I was wrong. The third time that their tower was struck, destroying
all of the lights and attached equipment, they followed my
recommendations. That was ten years ago. The three hits were within four
months of each other. The site has been free of destructive hits since
then.

73
Glenn
WB4UIV






--
---
Glenn LittleARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
---
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Re: [time-nuts] GPS antenna selection — lightning

[Glenn Little WB4UIV]

A very good reference for EMP protection is MIL-HDBK-419.
This is downloadable for a number of web sources.
It is about 600 pages and is in two volumes.
This discusses a number of different sources of EMP such as nuclear and 
lightning.
A lot is for protection of military industrial complexes, but, there is 
a lot that pertains to us.


I worked for a military complex that assembled nuclear missiles.
The site was built to this handbook specs.
We had no EMP related damage at the site.

Number one rule, bond all grounds together. If something on your 
property takes a hit, you want everything on your property to elevate to 
the same level and the same rate.
If you have multiple, non bonded grounds, there is a different reference 
for each ground. This is a major source for disaster.


I spent seven years in lightning mitigation. I was told by professionals 
that I was wrong. The third time that their tower was struck, destroying 
all of the lights and attached equipment, they followed my 
recommendations. That was ten years ago. The three hits were within four 
months of each other. The site has been free of destructive hits since then.


73
Glenn
WB4UIV



On 8/5/2016 10:37 AM, Eric Scace wrote:

Unfortunately, an antenna, cable, or piece of electronics located indoors is 
just as susceptible to lightning surges as one that is outdoors.

Lightning-induced surges couple into these systems electromagnetically across a 
wide range (VLF to SHF) of frequencies. When you think about your home from an 
electromagnetic viewpoint, just imagine your structure with all non-conductive 
materials absent. For a typical wood or brick/stone house in North America, 
what you are left with is:
metal plumbing pipes and fixtures, with their geometry suspended in space
house wiring, CATV, Ethernet, and telephone cabling, and their service drops, 
all suspended in space
electrical & electronic circuits of every kind (WiFi note, computer, 
appliances), their power supplies and AC power cords, also suspended in space
metal furniture? That’s hanging out there, suspended in space, too.
any I-beam or other steel structural elements, some random aluminum flashing, 
door knobs, and other similar metal construction materials used in the home.
That is what an electromagnetic pulse sees as it approaches and sweeps over 
your home… all hovering over a lossy ground plane (earth) its varying 
dielectric constant.. Each one of those pieces of metal, hanging in space, is 
an unintentional antenna that experiences voltage differentials and current 
flows.

A GPS antenna and its coax line that is installed next to a window is no 
different from the same antenna/coax installed one meter outside the window… or 
10 meters away outside the window. All three installations are effectively 
“outdoors” from an electromagnetic viewpoint, and all three need effective 
surge protection from lightning-, cloud-, and precipitation-induced voltage 
surges.

(N.B.: Snow can be particularly bad for voltage surges. I’ve seen thousands of 
volts per meter potential differences in moderate-to-heavy snowfall that 
produced very significant current flows on cables.)

Surge protection for your antenna, its attachment to your receiver(s), AC/DC 
power supply lines, and any other signal lines of significant length is cheap 
insurance.

My continuously-operating electronics lives in an enclosed rack cabinet — not 
too much worse than a proper Faraday cage. Every cable entering the cabinet has 
surge protection at the point of entry. The cabinet is bonded to earth ground 
by 2” copper flashing. In the past this system lived 22 years on a mountaintop 
home, 1200 ft above surrounding terrain. Lots of thunderstorms — zero 
damage/disruptions during that time… a sample size of one, admittedly, but 
during the first 18 months at that site I had two lightning-surge damaging 
events before I got serious about protection.

I have equipment at a coastal site with multiple 130-ft towers. That site had 
damage events every 2 years or so — even when cables to the “outside” were 
disconnected, and AC mains power was shut off at the main circuit breaker box. 
After implementing comprehensive surge protection, we have had zero damage over 
the last 12 years.

— Eric


On 2016 Aug 04, at 19:46 , Bob Camp  wrote:


Grounding the antenna is always a good idea.



A surge suppressor in the line could save you some
real cost if there is a lightning strike.


I did a quick search for SMA/BNC/TNC based surge
protectors and not much did come up, any suggestions
what to use there?


There are a *lot* of them on eBay. Many of them have N connectors on them.




I don’t know about Austria, but here in the US,
both are required.


Outside definitely, "inside" I'm not sure, but it
won't hurt to have additional protection for the
receiver(s).


It is a good bet that the antenna will be outside. I’d plan it that way.




___
time-nuts 

Re: [time-nuts] Q/noise of Earth as an oscillator

[Glenn Little WB4UIV]

In navigation we used the earth rate of 15.04 degrees per hour.
This was treated as a 'constant' even though it varied with wind, waves 
on the ocean and other things affecting the instantaneous rotational 
speed of the earth.


How does this factor into leap seconds, or, does it?

We accept that the day is 24 hours long, this would be for a earth 
rotational speed of 15.0 degrees per hour.


I am not a mathematician, but, I dis do electronic navigation on submarines.

73
Glenn
WB4UIV


On 8/1/2016 10:54 AM, Tom Van Baak wrote:

Hi Jim.


You said: "you need energy; you need energy loss; you need cycles over which that 
loss repeatedly occurs."
With regard to the earth, where is the first one?


By first one, do you mean where does the initial energy come from?

For a pendulum clock, you supply energy with a lift or a push. For a lift to 
the side, E = mgh, where h is the height above the base. For a push from 
center, E = 1/2 mv^2. Either way, it takes all the potential or kinetic E you 
provide and starts making time from there.

For a rotating clock, you just give it a twist. In this case, E = 1/2 Iw^2, 
where I is the moment of inertia and w (omega) is angular velocity. For earth 
the total E is 2.1e29 J. That's the energy number you want, yes?


Sure it was there at the start when the solar system formed, but where is it 
now?


I don't have data on where the initial swirl of solar system mass came from, or 
how much of that rotational energy went into our planet and its pesky moon, or 
Who or what gave that initial twist. The Q is pretty high so I assume you could 
work backwards, but I leave that to astronomers and cosmologists. I believe the 
2 ms/day / century estimate we use is one such measurement.

For more on earth rotation rate, UTC and leap seconds see 
https://www.ucolick.org/~sla/leapsecs/dutc.html

Surely in the literature there is a pile of information or speculation 
regarding all the rotational energy in the universe. It seems a common theme 
everywhere you look; maybe it was as much Big Twist as Big Bang? Perhaps in 
your Pulsar research you've run across some papers you could share. Off-list is 
ok, unless you think it has general time-nuts appeal. We're running the risk of 
spinning off-topic already.

Thanks,
/tvb

- Original Message -
From: "Jim Palfreyman" 
To: "Discussion of precise time and frequency measurement" 
Sent: Sunday, July 31, 2016 7:34 PM
Subject: Re: [time-nuts] Q/noise of Earth as an oscillator


Hi Tom,

You said: "you need energy; you need energy loss; you need cycles over
which that loss repeatedly occurs."

With regard to the earth, where is the first one? Sure it was there at the
start when the solar system formed, but where is it now?

Jim


On 1 August 2016 at 12:16, Tom Van Baak  wrote:


Hal:

Is there a term other than Q that is used to describe the rate of energy

loss

for things that aren't oscillators?


Jim:

cooling (as in hot things)
discharge (as in capacitors and batteries)
leakage (as in pressure vessels)
loss


Scott:

An irreversible process would be a better description versus energy loss.
Like joule heating (resistance, friction).


Notice that these are all energy losses over time; gradual processes with
perhaps an exponential time constant, but without cycles or periods. We
know not to apply Q in these scenarios.

But when you have an oscillator, or a resonator, or (as I suggest) a
"rotator", it seems to make sense to use Q to describe the normalized rate
of decay. So three keys to Q: you need energy; you need energy loss; you
need cycles over which that loss repeatedly occurs.

We use units of time (for example, SI seconds) when we describe a rate.
But here's why Q is unitless -- you normalize the energy (using E / dE)
*and* you also normalize the time (by cycle). No Joules. No seconds. So
having period is fundamental to Q. It's this unitless character of Q (in
both energy and time) that makes it portable from one branch of science to
another. And if you measure in radians you can even get rid of the 2*pi
factor ;-)

Without controversy, lots of articles define Q as 2*pi times {total
energy} / {energy lost per cycle}. To me, a slowly decaying spinning Earth
meets the three criteria. It appears to follow both the letter and the
spirit of Q.

Bob:

ummm…. Q is the general term of rate of energy loss and we just happen

to apply

it to oscillators in a very elegant fashion….


Oh, no. Now we have both quality factor and elegance factor!

/tvb
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- Original Message 

Re: [time-nuts] Need - PRS10 magic smoke

[Glenn Little WB4UIV]

My guess is the burned choke is in series with the Tantalum capacitor.
This is a very common failure mode for these Tantalum capacitors.
There are a number of things that will cause this failure.
1). power supply ripple too high (Tantalum capacitors do not like ripple).
2). Moisture absorbed by the Tantalum capacitor.
3). Voltage rating of the Tantalum capacitor too close to the supply 
voltage. ie a 6 Volt capacitor used on a 5 Volt supply.


The solution is to replace the choke and the Tantalum capacitor.
Replace the capacitor with a higher voltage capacitor.

A lot of high end test equipment is prone to Tantalum failure because 
the design engineer used the same Voltage safety margin for the Tantalum 
capacitor as would have been used for an aluminum electrolytic.


The Tantalum capacitor requires a higher safety margin because the 
Tantalum capacitor will short (as you experienced) by a spike above the 
allowed for safety margin. An aluminum electrolytic will absorb the 
spike, the Tantalum might short.


You should be able to recover the PRS10.

73
Glenn
WB4UIV


On 6/13/2016 6:32 PM, Skip Withrow wrote:

Hello time-nuts,

Well, broke out a PRS10 that I had put away for a project some time ago and
upon power up found that it had issues.  Status indicated low lamp output
and high lamp temperature.  Duh!  Upon removal of the lamp assembly it
became abundantly clear that the magic smoke had gotten out.

If I recall correctly, seems like there was another PRS10 with corrosion
issues in the same area.  My guess is that the heat does not help this
situation.  I suspect that I may have a full-on heater, which may have
caused the tantalum cap (and possibly other) failures.

Looks like this may be the weak spot in these oscillators.  I'm very
hopeful that a rebuild will bring it back to life.

Thought you would enjoy the pictures though.  Two are attached.

Regards,
Skip Withrow


Virus-free

<#DDB4FAA8-2DD7-40BB-A1B8-4E2AA1F9FDF2>



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--
---
Glenn LittleARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
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Re: [time-nuts] When does NIST change to DST?

[Glenn Little WB4UIV]

Does WWVB switch to DST, or, just set a bit in the data stream telling 
the device that receives the signal that DST is active?
I seam to remember (that is dangerous) that WWVB data has GMT time 
encoded into the data stream and that it is up to the receiving device 
to display the correct offset from GMT.


My buddy, Google, found the data WWVB transmits here:

http://www.nist.gov/pml/div688/grp40/wwvbtimecode.cfm

Hope this helps

73
Glenn
WB4UIV


On 3/13/2016 10:21 PM, Andy wrote:

I wonder if WWVB switches to DST around 0200Z, maybe?  Since it can't
tell where your local zone is.

Andy
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--
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Glenn LittleARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
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Re: [time-nuts] HP 10544A Repair

[Glenn Little WB4UIV]

While in the navy, I had to repair a hp cesium standard.
The control circuit had the oscillator slewed to one limit, I do not 
remember whether high or low.

We had no spare parts to support this standard.
The only option was to run the standard open loop.
Over a period of two hours, I had the standard off for no more than 15 
minutes total.
To get the standard back on frequency, I had to compare this standard to 
the other standard using an oscilloscope to produce a Lissajous pattern.

I set the oscillator on frequency by stopping the rotation.
I checked it again in 6 hours and the pattern was fastly rotating.
I reset the frequency and checked it at 6 hour intervals.
It took two weeks for the oscillator to thermally stabilize after being 
off only 15 minutes.

Be prepared to have to wait to get the oscillator thermally stabilized.

I am not positive that this was a 10544A, but, it was a similar ovenized 
precision oscillator.



YMMV

73
Glenn
WB4UIV


On 2/28/2016 8:10 PM, Bob Camp wrote:

Hi

Except ….

The big steps give you more “thermal shock” on a BT and that slows things down.

Bob


On Feb 28, 2016, at 7:28 PM, Richard (Rick) Karlquist  
wrote:



On 2/28/2016 7:01 AM, Bob Camp wrote:

Hi

It’s not an electrical issue as much as a heat issue ….

Before you start, consider that you will be doing something like:

Move trimmer 1 turn CW
Wait 10 minutes
read frequency
Move trimmer 1 turn CW
wait / read
Move trimer 1/2 turn CCW
wait / read
Move trimmer 1/4 turn CW
wait / read
Move trimmer 1/8 turn CCW
wait / read
Move trimmer 1/16 turn CW
wait / read
Move trimmer 1/32 turn CW
wait / read

That is indeed an ideal version. You likely will do multiple steps at each of 
the stages rather
than get it right the first time. The part needs to be warmed up for a few days 
before you
can get to the 1/32 turn level. You also need a good standard to compare to.

Bob



Instead of that, start with the pot at max temp, and have the counter make 
measurements at, say, 1 second intervals as the oven warms up.
You can tell by looking at the plot what the peak frequency is.  Now
that you know the peak frequency you are shooting for, it will take
a lot less trial and error to find the oven setting that produces it.

Rick
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--
---
Glenn LittleARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
---
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[time-nuts] Reference OCXO

[Glenn Little WB4UIV]

What would a shock mounted 10.08 MHz OCXO be user for?
Just another nonstandard reference?

Thanks
73
Glenn

---
Glenn LittleARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
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Re: [time-nuts] RG 6 U couplings

[Glenn Little WB4UIV]

If you do use 75 Ohm Type N connectors, do NOT attempt to mate them with 
a 50 Ohm connector.

The center pins are different diameters to get the different impedance.
To mate a 50 Ohm Type N male with a 75 Ohm female will guarantee 
destruction of the female connector.
I have had to clean up behind someone that dis not know the difference 
and took a large downlink dish off line as the spread fingers of the 75 
Ohm Type N broke off and shouted the cable and the LNB supply voltage.


There are also 50 and 75 Ohm BNC connectors, but, they achieve the 
impedance difference bu use of dielectric,

These connectors can be mated 50 to 75 Ohm with out damage.

Just to warn of the possible damage.

73
Glenn
WB4UIV

On 12/6/2015 10:16 AM, David J Taylor wrote:

David,

You obviously is not working with 75 Ohm N-connectors on a regular basis.

Also, the point was to show that using proper connectors isn't going to
be a major issue in the loss process.

Cheers,
Magnus


Magnus,

No, I've never seen a 75-ohm N connector, nor an N connector to fit
RG-6U cable.  What a sheltered life I've led!  But I quite agree that
for receivers, using 75-ohm components in a 50-ohm system (with care)
isn't an issue for an amplified GPS antenna.

Cheers,
David


--
---
Glenn LittleARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
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Re: [time-nuts] Time syncing WiFi routers using FM radio

[Glenn Little WB4UIV]

The house standard in some stations are no more than LC oscillators.
As long as the relative timing between signals is constant, you can do 
synchronous switching.
All signals go through as dedicated frame synchronizer that is 
synchronized to house reference.
At the last station that I worked at, our house reference had drifted 
off where it should have been.
To reset it would have required retiming all of the production 
switchers, the cameras and the on air switcher.

There was no cesium standard at the studio nor at the transmitter.
The transmitter was crystal controlled with the crystal in an oven.

Now there is no sync transmitted like in the analog days.
There is a very accurate pilot that can be seen in the signal.
The exciter is synthesized with a crystal bases reference.
Most transmitters can take an external reference, but, the stations that 
I have worked for do not use it.



73
Glenn

On 11/12/2015 2:17 PM, Hal Murray wrote:

And the decade before that the hp house standard looked like this:


Has anybody made a graph of the accuracy of house standards over time?  I'm
looking for something like Moore's Law.




--
---
Glenn LittleARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
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of the Amateur that holds the license"
---
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Re: [time-nuts] Clock Driver Design

[Glenn Little WB4UIV]

Would an analog video distribution amplifier work?
These are available cheap.
TV stations used these eight or so in a frame.
The frame had a power supply and the BNC i/o connectors.
Each da would drive 6 or 8 outputs.

73
Glenn
WB4UIV
Retired TV CE.


At 01:28 PM 9/26/2013, you wrote:
I am looking into various degrees of craziness.  The source is CMOS 
and there are plenty of 1 in to N out parts designed to drive clocks 
on a PCB but not much is said about driving clocks on to a random 
length of coax to another piece of equipment and what additional 
precautions that might warrant.  I am also considering making a sine 
wave output and maybe other frequencies.

Tom

On 9/26/2013 4:34 AM, Bob Camp wrote:

Hi

Standard high speed CMOS logic works pretty well. How crazy are you 
trying to get?


Bob

On Sep 26, 2013, at 1:48 AM, Tom Minnis tom_min...@att.net wrote:

I am working on a small clock distributor and wanted to get some 
ideas on what works best for 10MHz and 1PPS driver circuits.  I 
remember sifting through the archives a year or so ago and tripped 
on some discussion of this but I can't find it anymore.

Tom
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Re: [time-nuts] Warped back to 1993

[Glenn Little WB4UIV]

With the wrong date and time, the GPS should not find almanac data, 
so will not lock.


This was the problem caused by the 1024 week roll over problem.
Are we possibly at week 2048??

73
Glenn
WB4UIV

At 11:28 PM 8/10/2013, you wrote:


ma...@non-stop.com.au said:
 Hal, I can't get it to take, I keep getting E-350 and the time does not
 change. Did you unplug the antenna or anything while you changed date?

I don't remember doing anything like that, but it was a long time ago.

I may have told it the date while it was doing a survey.

The text in the Z3801A manual doesn't say anything about the 1024 week
problem.  It does say first satellite, so I'd unplug the antenna and power
cycle the box and see if that would let you set the date.


--
These are my opinions.  I hate spam.



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[time-nuts] HP-117A

[Glenn Little WB4UIV]

Are there any tricks to getting a HP 117A to lock to the current WWVB 
transmissions.

I have read the thread for the Spectracom receivers.
Will this work with the 117A?

Thanks
73
Glenn
WB4UIV




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Re: [time-nuts] Odd FTS 4060 Behavior

[Glenn Little WB4UIV]

This is known as gold embrittlement.
The gold has to be removed before a good solder connection is made.
To remove the gold, tin the gold plated area.
Desolder the tinning.
Retin and remove the solder three times.
This should remove the gold which forms an amalgam with the solder.
After the gold has been removed, a reliable solder connection can be made.

This is a common failure mode of radio power amplifiers.

If you can undo the connection without adding heat, you will see a 
black area between the gold plating and the solder.


I do not know why the manufacturers insist on gold plating leads that 
are designed to be soldered.

Silver plating seems like a better solution.
In this case, it appears that pins were soldered that were not 
designed to be soldered.


Glad that you found the problem.

73
Glenn
WB4UIV



At 06:40 PM 6/13/2010, you wrote:

Interesting.  Solder and gold don't like each other very much, and even the
more respected manufacturers don't always seem to appreciate that, when they
rely on a soldered connection to provide some mechanical stability.  This
isn't the first time I've heard of FTS oscillators behaving oddly, so it'd
be great if they could be fixed this easily.  Pinning down an exact cause
might be helpful to others if the problem shows up again.

One other thing that can go wrong with OCXO testing happened to me last
night.  A high-grade unit that I'd borrowed was exhibiting some severe
frequency jumps of around 6-8 Hz, visible on a couple of different counters.
I decided to watch it for awhile in case it was still settling down from
being moved, and work on some other things.  Before long, I started seeing
flaky behavior from other equipment such as a signal generator and spectrum
analyzer, and the lock indicator on a 100 MHz PLL being burned in on the
rack also started flashing intermittently.

Turned out that I had accidentally left my 10 MHz distribution amp hooked up
to a 'public' Thunderbolt that's used for testing remote access via Lady
Heather and not normally connected to anything.  Someone had logged in,
probably thinking they were talking to their own local unit, and set the
Thunderbolt's position manually to a rooftop near Sydney, in New South
Wales...

-- john, KE5FX


 The OCXO out of the 4060 and connected to a bench power supply with no
 tuning voltages applied had to be trimmed to get on 10 MHz.
 After a while it started temporarily jumping to -1.4E-07, which could be
 reversed or provoked by knocking it on the head.

 I decided to disassemble it and found a neatly built dewar insulated
 oven inside. I just didn't like the solder joints of the gold plated
 edge connector pins on the two PCB's inside the oven that had separated
 on the component side from some of the pins. So, I resoldered them and
 stuffed everything back in the jar. After powering it up, I had to trim
 it back by about the same amount it needed in the beginning when it
 appeared to be in 'failure mode'. At the moment it appears to be no more
 vibration sensitive, but that doesn't necessarily mean I got it fixed.

 Now it's back in the 4060 (without readjusting it, the tuning voltage is
 almost exactly at center scale!), and we shall see if it behaves or not.



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Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs

[Glenn Little WB4UIV]

These were used on some measuring instruments to provide a balance 
'guarded' input.
The shield around the balanced conductors provided a ground between 
the DUT and the measuring equipment that was not connected to the input.

IIRC this was for very low level signals.

73
Glenn
WB4UIV


At 10:06 PM 2/27/2010, you wrote:

Hi

Sure never seen any of them on any gear in my junk pile.

I also never seen a customer ask for them as an output connector on 
an oscillator. I wonder how common they actually are.


Bob


On Feb 27, 2010, at 9:59 PM, Bruce Griffiths wrote:

 Actually there are miniature twinax style connectors, for example:
 
http://www.amphenolrf.com/products/twinbnc.asp?N=0sid=4B8860805409E17F; 
http://www.amphenolrf.com/products/twinbnc.asp?N=0sid=4B8860805409E17F;


 Bruce

 Bob Camp wrote:
 Hi

 I don't even have the counter and already we're butchering it

 The big issue is suitable twin-ax connectors and cable. I have 
both, but they are *big*. They never really made it into the world 
of miniature connectors and miniature cable.


 Shielded twisted pair would be another option. That eliminates 
the cable as an issue. Small connectors (BNC drop in) are still an 
issue though.


 Bob


 On Feb 27, 2010, at 9:48 PM, Bruce Griffiths wrote:


 Since the input amplifier and trigger circuit are located on a 
small daughter board it wouldn't be too difficult to replace this 
with an LVDS to CML stage.
 The only remaining isue would be what input connector to use 
(twinax??, SATA??).


 Bruce

 Bob Camp wrote:

 Hi

 Gee, LVDS what an unusual approach :)

 It would be nice if these instruments had a balanced input. 
Common mode noise is indeed an issue in a lot of cases.


 Of course wrapping the coax headed to the counter 10X around a 
fairly large core can help things a bit.


 Bob


 On Feb 27, 2010, at 9:32 PM, Bruce Griffiths wrote:



 If one is feeling paranoid about ground loop noise (and 
wishes to avoid transformers, optoisolators , or fibre optics), etc 
one could always use an LVDS driver with a batter powered(?) LVDS 
to CMOS receiver/translator right at the 5370A/B input BNC connector.

 This may be useful for a DMTD system that uses a 5370A/B.

 Bruce

 Bob Camp wrote:


 Hi

 AC cmos will easily drive an L pad to match a 50 ohm cable 
at these levels. That's true at either 3.3 or at 5.0 volts. There 
are a lot of cmos families out there that beat AC for speed and 
match the output drive capability.


 Bob


 On Feb 27, 2010, at 9:12 PM, Bruce Griffiths wrote:




 1) One method with 5V CMOS is to add a resistive voltage 
divider at the CMOS driver output with a 50 ohm output impedance at 
the tap that drives the 5370A/B input.


 2) If one has a 5V 50 ohm driver (eg Thunderbolt PPS 
output) use a 50 ohm attenuator at the 5370A/B input.

 For a 5370A an attenuation of at least 11dB is required.
 For a 5370B an attenuation of at least 3dB is required.

 3) One can always use the 10x input attenuation setting 
built in to the 5370A/B however this reduces the signal swing to 
0.5V at the trigger amplifier input (5V CMOS input).


 4) Attenuate the output of the logic signal by a factor of 
2 and use an npn emitter follower to drive the 50 ohm load.


 5) Use 3.3V CMOS signal levels for the 5370B.

 6) Use a current mode emitter or source coupled switch to 
drive the 5370A/B input.


 The switching jitter of the above drivers will be much 
lower than the internal noise of the 5370A/B as long as HCMOS or 
faster logic is employed.


 Bruce


 Bob Camp wrote:



 Hi

 Which *still* carefully avoids the issue of how .

 Bob


 On Feb 27, 2010, at 8:52 PM, Bruce Griffiths wrote:





 Oops! a small correction (2nd paragraph):

 For the 5370A attenuating the 5V CMOS signal to a 1V 
swing with the threshold set to 0.5V is close to optimum.
 An input signal with limits of 0V and +1.4V with a 
trigger threshold of 0.7V is the maximum usable (for high performance).
 An input signal with limits of 0V and +0.3V with a 
trigger threshold of 0.15V is the minimum usable (for high performance).


 For the 5370B attenuating the 5V CMOS signal to a 2V 
swing with the threshold set to 1V is close to optimum.
 An input signal with limits of 0V and +3.5V with a 
trigger threshold of 0.7V is the maximum usable (for high performance).
 An input signal with limits of 0V and +0.3V with a 
trigger threshold of 0.15V is the minimum usable (for high performance).


 Thus using the PPS output (~270 ohm is series with a 5V 
74AC04 output) from a Synergy evaluation board that uses an M12M or 
M12+ GPS timing receiver to drive the inputs (with a 0-750mV 
signal) of a 5370A or 5370B is well within the recommended input 
signal range for high performance.
 This avoids having to adding an external 5V 50 ohm driver 
that some would use.


 Bruce

 Bob Camp wrote:




 Hi

 So exactly how did you know that I bought a (cheap) 
5370B a few hours ago on the e-place  and was just about to ask 
about how best to use 

Re: [time-nuts] ABC time signals in Tasmania/Australia wrong

[Glenn Little WB4UIV]

If the TV station was transmitting digital and they were passing a 
network signal, a 5 second delay is possible.

The network encodes the TV signal, then transmits it digitally.
There is a finite amount of time involved with the digital encoding 
of the signal.
There is a finite delay for the transmission of this encoded signal 
from the network uplink to the TV station receiver.

The TV station decodes the signal, a finite amount of time.
The TV station possibly processes the network signal, more time.
The TV station processes the output of their switcher in the 
transmitter encoder, more time.
The TV station transmits the signal from the studio to the 
transmitter, possibly more processing and time.

The TV receiver receives the signal and decodes it for display, more time.

With all of the processing, encoding and decoding of the digital 
signal, a 5 second delay is not unheard of.


73
Glenn
WB4UIV
CE WCIV TV


At 10:56 PM 1/2/2010, you wrote:

Hi Jim,


In Sydney, many months ago, the ABC time signals were absent.
I rang them and the technician explained that they use a PC program to
produce them, and they had to reboot the computer to start them up
again.
So I dont know where they get the time, either off the net? or from a
PPS signal
from a GPS?
Either way they do not use the old observatory signals that came from
the PMG.

A local TV station counting down to the new year was 5 seconds out!

cheers, Neville Michie

On 03/01/2010, at 12:14 PM, Jim Palfreyman wrote:


For the Down Under nuts,

The ABC radio time signals in Hobart are one second out. Is it a
national
thing? Can others in the country check?

I rang the ABC locally on xmas eve but it is still not fixed.

Jim Palfreyman
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Re: [time-nuts] Help identifying coax connector type

[Glenn Little WB4UIV]

The larger push on connector is an SMP.
This is used a lot in microwave for IF cables.
This is a 75 Ohm connector.

73
Glenn
WB4UIV

 At 03:38 AM 12/7/2009, you wrote:
I have recently acquired a number of nice coax parts, but I'm not 
sure exactly what connector types they are. If anybody can help me 
identify them, I'd appreciate it!


First, are these spiffy jacks. They look somewhat like SMB, but are 
too large as far as I know. Too small for BNC, and there's no bayonet.


http://www.flickr.com/photos/24004...@n03/4165880386/
http://www.flickr.com/photos/24004...@n03/4165880282/
http://www.flickr.com/photos/24004...@n03/4165880166/


Next is this coax jumper cable. Unknown connectors on both ends:
http://www.flickr.com/photos/24004...@n03/4165122135/
http://www.flickr.com/photos/24004...@n03/4165122541/
http://www.flickr.com/photos/24004...@n03/4165122411/

Last is another cable, with yet another unknown connector on it:
http://www.flickr.com/photos/24004...@n03/4165881034/

Thanks!

-Pete
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[time-nuts] Z3801A Power Supply

[Glenn Little WB4UIV]

Does anyone have a schematic for the Z3801A internal voltage converter board?
I will attempt to reverse engineer it if one is not available.

73
Glenn
WB4UIV




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Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy)

[Glenn Little WB4UIV]

And all the GPS goodness can easily be disabled by a missile and a 
near nuclear burst or a portable handheld jammer at the airport.
The portable handheld jammer is a very real threat to GPS due to the 
signal levels from the satellite.


Now they are trying to revive a miswired SVN and add it to the network.

It is very hard to jam the LORAN signal without a high power jammer.
If a LORAN station is taken out by enemy action, it is not 
unreasonable to rebuild or replace it.


GPS is just too fragile to be heavily relied on.

I know that we do it every day, but, you need to have a backup 
navigation system.


LORAN is time proven to be functional and the technology is in place 
on a number of platforms to utilize it.



73
Glenn
WB4UIV
ETCS(SS) USN Retired (Electronic Navigation)

At 10:21 PM 11/14/2009, Francesco Ledda wrote:

LORAN is a good back up, but it has problems and limitations.  Navigating
next to a storm can overwhelm the receiver and make it unusable.  The LORAN
system doesn't have a build in accuracy degradation system like GPS(RAIM -
receiver autonomous integrity monitoring), and this make LORAN unfit to fly
Non-Vertical Guidance approaches. GPS with its accurate positioning, fast
update rate and WAAS make is an awesome aircraft navigation system that can
replace almost all NAVAIDS including ILS. Today with GPS, we can fly in
instrument conditions from take off to landing without ever tuning any
external NAVAID; not even INS can't do that. It is pretty amazing to me!






-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
Behalf Of Hal Murray
Sent: Saturday, November 14, 2009 7:13 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference
oscillator accuracy)



 I've read and heard from this forum as well as a number of other
 sources that GPS can be easily jammed.  What makes GPS so vulnerable?
 How can it be jammed?

The signal is very very very weak.  The question is not how can it be
jammed,
but rather how can you find the signal at all.

There was a recent message here reporting on the 5th harmonic of a small 315
MHz radio link wiping out GPS for a 1/2 mile:
  http://www.mail-archive.com/time-nuts@febo.com/msg22033.html

Here is a good story:
  Unjamming a Coast Harbor
  James R. Clynch, Andrew A. Parker, George Badger,
  Wilbur R. Vincent, Paul McGill, Richard W. Adler
  GPS World, Jan 1, 2003
  http://www.gpsworld.com/gps/system-challenge/the-hunt-rfi-776



--
These are my opinions, not necessarily my employer's.  I hate spam.




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[time-nuts] Setting Oscillator Frequency

[Glenn Little WB4UIV]

I just got a system that allows me to compare the phase difference 
between a reference and an external oscillator.
I am using a Vectron oscillator installed in a  HP 5345A counter as 
the external oscillator and a PTB-100 as the reference.

How close to the reference should I be able to set the OCXO?
After a 3 day warm up, it appears that I have gotten the OCXO to 
within 0.0025 Hz of the Rubidium reference.
I am checking with a strip chart recorder over a three hour period 
for the next few days to see if the OCXO stays at this accuracy.
Is it really possible to set an OCXO this close or have I made some 
errors in my computation of frequency offset?


Thanks
73
Glenn
WB4UIV


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[time-nuts] Reference oscillator accuracy

[Glenn Little WB4UIV]

While I was in the US Navy we had two Cesium standards for the 
navigation center on SSBN submarines.
While in port, we would track LORAN C and compute the drift rate of 
the two cesium standards.
Is there a service, that has drift rates published, that I can 
compare my standards to, so that I can determine the standard drift rate.
I do not remember the drift rates that we determined on the 
submarine, that was a few years ago, but, I seem to remember that the 
rate was in the low nanoseconds.
If a rubidium standard drifts in one direction (does it?) a drift 
rate could be calculated and, after a comparison to a known standard, 
with known drift rate, a very accurate standard could be had for the lab.


What would I expect the drift rate, or jitter, to be in a FRK class 
rubidium oscillator?


Is the drift rate constant enough that a drift rate could be applied 
to a rubidium oscillator to determine it's real frequency at any given time.


We calibrated the submarine Cesium standards every three months.
We had to know the drift rate of our standard as well as the drift 
rate of the standard in each of the LORAN stations to be able to do 
the type of LORAN navigation that we did.


I would like to be able to verify that my PTB-100 rubidium oscillator 
is on frequency.


If I compare two rubidium oscillators, what would I expect the 
relative drift rate to be?


Thanks
73
Glenn
WB4UIV




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[time-nuts] Rubidium standard

[Glenn Little WB4UIV]

I was told by a Technical Support Engineer from Symmetricom Global 
Services that

The typical life span is ~10 years for these Rubidium Time Bases.

This is in response to my request for information on a Ball/Efratom PTB-100.

Is this a typical life span of a rubidium standard?

Do some standards last longer than others?

What are the symptoms of a failing rubidium bulb?

Thanks
73
Glenn
WB4UIV






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[time-nuts] WWV Clock

[Glenn Little WB4UIV]

My WWV clock at home and the master clock at the TV station that I am 
engineer for did not update to EST from EDT.

Did anyone else see their WWV clock not change time for DST?

Thanks
73
Glenn
WB4UIV




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Re: [time-nuts] OT: Spectrum Analyzer

[Glenn Little WB4UIV]

Keep in mind that anything much newer than the 141T will have custom 
parts and processors.

This makes the instrument smaller and more versatile, but, less repairable.
The 141T is a workhorse.

I would not trade mine for any number of the processor controlled analyzers.
Having a nice clean analog display is nice and you do not have to 
worry about did I get an accurate display of what I am looking at or 
did what I am looking for occur between sample on the digital display.


I hope you find what you are looking for. It is hard to beat the 141T 
for a spectrum analyzer.


73
Glenn
WB4UIV

At 11:06 PM 10/30/2009, you wrote:
I'm thinking of buying a spectrum analyzer and would like to know 
what Time Nuts recommend.  My requirements are fairly simple:


3GHz Max frequency or higher
Either GPIB or Ethernet interface for control and data capture
Not much larger than an average desktop computer.  Portable is nice 
but not necessary.

Preferably under $3000.

I thought about building Scotty's Spectrum Analyzer or Poor Man's 
Spectrum Analyzer, but decided I would rather buy one then build one.


I have an HP 141T but I am looking for something more modern.  One 
of my uses will be looking at C and Ku band satellite signals (down 
converted to 950-2050 MHz).  I'll also be using it to look at 
various RF data links from 433 MHz to 2.4 GHz.


Thanks,
Brent

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[time-nuts] Oscillator comparison

[Glenn Little WB4UIV]

I have just recently bought a working HP 5345A counter.
Much to my surprise, I find that the oscillator is a Vectron 2810007-11.
The early 5345A counters used a 10544 oscillator, while the later
ones used a 10811.
Can any one tell me what the real difference, in operation, is
between the HP 10544 and 10811 oscillators?
I understand that the 10811 is a later design using a SC cut crystal
while the 10544 used an AT or BT cut crystal.
I understand that the 10811 is faster to warm up.
In a counter that has the OCXO oven on all of the time, is there an
advantage of the 10811 over the 10544 oscillators?
Where does the Vectron 2810007-11 oscillator fit in? Vectron tells me
that this was made to HP specs. What specs?
The Vectron oscillator shows up as a bid item for the military for a
replacement oscillator for the 5345A counter.
Which oscillator does it really replace?
Is there an advantage of the Vectron oscillator over the HP oscillators?
If so what?

Any help greatly appreciated.
I would like to have as stable an oscillator as possible in my counter.
Just need to know what is functionally the best.
IE, without knowing what oscillator is in the counter, is there an
operational way to tell?
Warm-up time? Accuracy? Phase noise?

73
Glenn
WB4UIV









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Re: [time-nuts] Gold plating on aluminum

[Glenn Little WB4UIV]

To plate gold on copper requires the copper be first nickle plated.
Then the gold is plated onto the nickle.
Gold will not directly plate on copper.

73
Glenn
WB4UIV

At 03:36 PM 10/20/2009, you wrote:
In message 80f9fcf76d3642698820a10169603...@pc755913417801, Nic 
McLean writ

es:

If you wish to do it yourself have a look at the products from Spa Plating
at http://www.goldn.co.uk/. I use their products they are really cool.

Hmm, do you know if that is any good for goldplating homemade PCB's ?

--
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.

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Re: [time-nuts] hp10811 OCXO shipping jolt/drop survival?

[Glenn Little WB4UIV]

A 4.35 milli-Hertz(mHz)deviation is not bad at all. If you meant 4.35 
Mega-Hertz (MHz). There are a few orders of magnitude between these 
(10^-3 to 10^6).
The proper use of units is important. In some cases this improper use 
of units can be understood due to the wrong units cannot apply. In 
this case the possible wrong units could apply, so, you need to use 
the correct units so that there is no misunderstanding.


Did you mean mHz or MHz??



73
Glenn
WB4UIV

At 03:21 AM 10/10/2009, you wrote:

Bruce Griffiths wrote:

swingbyte wrote:


HI all ,
I had a 5370 A shipped to me that suffered enough of a drop/roll to
break a handle and bend the chassis such that the bottom panel had to
be modified to get it back on.  When I connected the timebase output
to the start input the frequency display is 10.000xx with the last
two numbers moving about quite a lot.  Could this indicate damage to
the oscillator due to the drop?  I haven't tuned up the inputs yet so
this may be an artefact of that.
Thanks

Tim



Tim

What gate time was used to measure the frequency?

Bruce


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Hi Bruce,
With a 1s gate time it ranges from 9.999 999 996 to 10.000 000 012 MHz
The 5335 with a 1s gate time gives 10.0101 with the last digit 
flickering 0.   Of course what's really bad is I have two clocks to 
check now.  The std deviation  as measured by the 5370 of the 5370 
clock is ~1.8 kHz while the std dev of the 5335 clock is 7.8 kHz - 
both have 10811 OCXOs.. The 5335 measures the 5370 clock  std dev as 
4.35mHz.  I think I'll have to check these against the Rb as I don't 
have a GPSDO yet.

Thanks

Tim


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Re: [time-nuts] HP 106B part no.

[Glenn Little WB4UIV]

1854-0003 is a good part number. I have a few here that were removed 
from equipment.
Possibly someone with the proper equipment could characterize this 
part and determine a suitable parametric substitute.


73
Glenn
WB4UIV

At 11:43 AM 8/9/2009, you wrote:
Double check: Q11 is marked as 1854-0003.  I can't find it in any 
of the HP cross references.


Brian - KD4FM


Jim Palfreyman wrote:

Hi all,

Latest update.

With some help and phone calls from Bill the fault seems to have been
isolated. I have removed Q11 from inside the oven and it is cactus. Q9
is also very suspect so I'm going to replace that for good measure.

Q9 is a 2N1701 in a T08 package. Thanks to various people I should be
able to track one down. Q11 is marked as 1854-0003 and that's an HP
internal number and all I know. Might have to substitute that one.

After all this I have some quality photos and can knock up some good
descriptions of the repairs and the 106B internals if anyone is
interested. Any websites hanging around that want to take what I have?

Regards and thanks to all!

Jim Palfreyman


2009/8/9 Adrian rfn...@arcor.de:


Re-read Jim's posts.

To me it seems clear that he is talking about the 2N1701 Q3 in the upper
right corner of fig. 5-12.
He mentioned that +18 measures high, around 26V.
So, the problem is NOT in the battery charger circuit.

The purpose of that Q3 is to generate +17.4V (and +7V) from +26V, with the
base being connected to +18V, thus the emitter voltage of Q3 is +18V - 0.6
to - 0.7V.

The +18V regulator circuit is on the lower left of fig 5-8, A1A4 Outer Oven
Controller. For a circuit description see 4-40 to 4-44.

The +18V feed the AC amplifier (A1A2), the +15V through R14 (might be cooked
if run at 26V for extended time) and CR2 on the same board, the power
amplifier (A1A3), the outer oven temperature control circuit (decoupled
+18V), and the inner oven control cuircuit A1A5.
The 17.4V that are derived from +18V feed the dividers.

Any adjustments make sense only after fixing the +18V supply.

Actually, Q3 might as well be shorted. I would first remove it from the
circuit to see if the +18V are then correct.
If not, check the voltages at Q9 and Q7 of A1A4. Q9 is mounted on the oven
housing cover.

Regards,
Adrian

Bruce Griffiths schrieb:


christopher hoover wrote:



 The 2N1701 is a general purpose transistor rated at 60V, 2.5A.



I've mentioned this before, but it bears repeating.

If you are having trouble with an old school linear power supply, in
many cases you can replace the TO-220 PNP pass transistor *and* the
reguatlor circuit (based on a 723 or whatever) with a modern
integrated regulator in TO-220 such as an LT1581.  Strip the regular
board of everything except for the the input and output caps (if they
are still good) and wire up a pair of resistors to set the voltage.  Add
a couple of jumpers to complete the circuit.   And then you are
good to go.

-ch




That probably wont work in this case.
The supply is actually an NPN discrete darlington buffered 32V zener
with a current limit transistor to set the battery charging current to
one of 2 values.
With the battery removed the supply output should rise to 32V - 2Vbe - a
diode drop, ie about 29.8V or so.
The series diode is required to isolate the battery from the regulator
output when the main fails.
It should be much quicker and easier to just find suitable transistors.

Bruce


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Re: [time-nuts] Time/freq from digital TV

[Glenn Little WB4UIV]

The digital transmitter could have a GPS based frequency reference.
I am the CE for a local station (WCIV).
We do not use any standard other than what is installed in the transmitter.

I have not verified it, but, I think that the UHF transmitter 
frequency is controlled by an OCXO.


I will try and remember to check on this Monday.

I do know that our Analog transmitter used an ovenized crystal  for 
frequency control. We were on channel 4.


We definitely are not slaved to the network for frequency control.

73
Glenn
WB4UIV



At 06:18 PM 6/13/2009, you wrote:


My radio has many news stories about the end of analog TV.

What sort of time or frequency can I get from a digital TV signal?

Now that frame buffers are common, does each station use its own master clock?

--
These are my opinions, not necessarily my employer's.  I hate spam.




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Re: [time-nuts] Time Signals on TV signals

[Glenn Little WB4UIV]

It appears that the time information is transmitted in line 21 of the 
analog TV signal.

This is the same line that carries Close Captions in an analog signal.
It further appears that PBS is the major carrier of these time signals.
See : 
http://simson.net/ref/autoclock/Interface-June-01.pdf#search=%27PBS%20time%20signal%20auto%20VCR%20set%27


This may explain why you are having problems.

I do not know how this is handled in the DTV world.

We translate line 21 captions to CEA-608 and CEA-708 captions for out 
DTV transmissions.


See: 
http://ncamftp.wgbh.org/DTV/CEA%20test%20material/Iteration_1/It1.2ReadMe.pdf


This explains a little about the conversion of analog line 21 to DTV captions.

It is possible that you can set your recorder to read 608 captions?

Hope this helps.

73
Glenn
WB4UIV
CE WCIV TV

At 12:52 PM 5/25/2009, Bill Hawkins wrote:

Aficionados of accurate time,

I have two Panasonic DVD TV recorders, a DMR-EZ27 and 28. They were set to
automatically sync time to a TV station. This worked fine until a few months
ago. Now they are on manual time, but, of course, they drift.

Tried to turn automatic time setting back on this morning. The screen says,
This may take a few minutes. It still said that 10 minutes later, as the
busy indicator continued to rotate through three spots.

Gave up on automatic and asked the only group I know that might know.

Why did TV stations stop broadcasting time signals? HDTV requirements?

Could a cable company interfere with the time signals?

Thanks,
Bill Hawkins


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Re: [time-nuts] WTB: 10 Volt L1 L2 GPS Antenna

[Glenn Little WB4UIV]

You could put a regulator on the voltage line for the antenna so that 
you could use a 5 Volt antenna.


This would get you away from the specific voltage requirements for 
their antenna.


73
Glenn
WB4UIV

At 09:54 PM 5/20/2009, you wrote:

Hi:

I just got an Ashtech Z-12-R Reference Station and it needs the 
subject antenna. http://www.prc68.com/I/AshtechZ12.shtml


I've got a bunch of GPS antennas but none with the needed 
combination of features.  It would be good to learn which antennas 
are 10 Volt types.
For example is the Trimble 4000ST L1 Geodetic, Model 14177-00 a 10 
Volt antenna?

http://www.prc68.com/I/Trimpack.shtml#4000STant

--
Have Fun,

Brooke Clarke
http://www.prc68.com


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Re: [time-nuts] fleabay cesium

[Glenn Little WB4UIV]

When I was serving in the US Navy we quit using Rubidium standards 
for Submarine radio and started using Cesium standards.
We also had a pair of Cesium standards that were used for timing in 
the navigation system.
I was told that the change was due to the Cesium had better long term 
stability than the Rubidium standard.
Every three months we calculated the drift rate for both of the 
navigation standards. We used LORAN for the reference.
Radio sent their standards to the submarine tender calibration lab to 
be calibrated.

The problem that we had with the Cesium standards was tube life.
The tube can be very expensive.

73
Glenn
WB4UIV



At 12:19 AM 5/9/2009, you wrote:

OK, dumb question time.

I have a few GPSDO's (Trimble T-Bolt, Z3801A, TrueTime  HB units).
How much better can the Cesium be than any of those ??

73, Dick, W1KSZ

-Original Message-
From: ewkeh...@aol.com
Sent: May 8, 2009 12:53 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] fleabay cesium

The cesium is from the same source as the two HP 5062. A friend of 
mine is selling them for me. I am in the process of cleaning house 
and that is also where the FTS1200 came from. More things are to 
come. I think this one is a later model because it has the newer 
power supply board and the DC cesium oven controller. I think it is 
the one unit. It should say in the description. I know I tested it, 
also measured beam current with the LF test. It des not have the 
two lights but during test they where installed and the pictures 
are of the actual unit. If you want to know any thing else please 
let me know.? Bert Kehren Miami



-Original Message-
From: Brian Kirby kilodelta4foxm...@gmail.com
To: precise time and frequency measurement time-nuts@febo.com
Sent: Fri, 8 May 2009 12:06 am
Subject: [time-nuts] fleabay cesium


seems to be a decent price cesium for sale ($600 starting HP5061A)?
?
http://cgi.ebay.com/HP-5061A-Cesium-Beam-Frequency-Standard-WORKING 
_W0QQitemZ250415440530QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item3a4dec6292_trksid=p3286.c0.m14_trkparms=72%3A1205|66%3A4|65%3A12|39%3A1|240%3A1318|301%3A1|293%3A1|294%3A200?

?
nobody has bid and 21 hours left...?
?
just a heads up - I know nothing about the unit or the dealer...?
?
Brian KD4FM?
?
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Re: [time-nuts] Datum/Trimble 9390

[Glenn Little WB4UIV]

I have a 9390-5593 that does not display the correct date.
The GPS engine uses two processors and three ROMS.
These are glued together with an ASIC.
I contacted Trimble and they cannot identify their engine.
I have read the ROMs and am in the process of disassembling the code.
This is slow.

I suspect that my 9390 had a Y2K problem and/or a 1024 week rollover problem.

Is this possibly the same engine that you replaced the ROMs in??

73
Glenn
WB4UIV



At 12:04 PM 3/24/2009, you wrote:
We use the Trimble 9390 where I work.

Around the Y2K period we received new EPROM sets to put into the units.

I checked yesterday and they are displaying the correct day and year.

Let me see if I can find a spare set of EPROMS to download.

Corby Dawson

Click to compare mortgage rates.  No obligation, quick and easy.
http://thirdpartyoffers.juno.com/TGL2141/fc/BLSrjpTIsOciybYp6dYJyzaPzRJYruNwXO5b3bh5IyhIHQW5QXYxE9p3k8w/

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[time-nuts] Motorola KXN1132AA

[Glenn Little WB4UIV]

Recently there was a post about oscillator stability and I thing 
drift over time.

Was the large Motorola oscillator the one in the subject line?

Further markings on the oscillator are source code 9896, Cust No 48R83851N02.

This is a 5 MHz operating frequency oscillator.

There are 8 lugs to interface the oscillator. Pin 4 is plus and pins 
2 and 3 are negative.
I think that this oscillator is an OCXO and works on 24VDC.

Can this oscillator be disciplined?

What are the other pins for?
What is the oscillator accuracy?

Thanks
73
Glenn
WB4UIV




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Re: [time-nuts] Motorola KXN1132AA

[Glenn Little WB4UIV]

I will try and locate a digital camera.

The oscillator is in a tin plated steel box.
The dimensions are 5.25x3x3.
On one 3x3 side, in the center, is a screw that hides an adjustment screw.
On the other 3x3 side is the BNC output connector and a ring of 
terminals about the diameter of a 9 pin tube.
There are 8 terminals. Two are for negative power and one is for 
positive power. The power source is 24VDC.
Also on this side is a screw in the upper right hand corner. This 
screw is soldered to the case.
On one of the 5.25x3 sides (the bottom) is four mounting studs. These 
are 6-32 and are at the corners of an imaginary 2x4 rectangle 
centered on the 5.25x3 side.
The side that has the BNC connector and terminals is soldered into 
the rest of the case.
There are two dimples to two sides of the box to stop this piece from 
going too far into the box.

73
Glenn
WB4UIV




At 08:08 PM 1/24/2009, you wrote:
Glenn

Other leads may include an EFC input.

As long as the oscillator frequency can be adjusted electronically
(usually via EFC) it can be disciplined.
If the oscillator lacks EFC then you may have to resort to using it in a
DDS or equivalent so that the output frequency can be adjusted.
The only drawbacks with a DDS are the spurs and elevated phase noise.
If you use a DDS the control system output must be digital, however an
EFC DAC isn't required.
There are techniques available for canceling spurs and/or reducing their
amplitudes significantly however these techniques add some complexity.

Can you post an image of the oscillator?

Bruce

Glenn Little WB4UIV wrote:
  The oscillator was bought as part of a scrapped Motorola base station.
  I was told that it was a PURC.
  The only leads attached to the oscillator are the power and the BNC
  output connector.
 
  Would this oscillator be able to be disciplined?
  What would its accuracy be as the basic oscillator?
 
  There was no GPS in the parts that I got.
 
  The oscillator is large enough to be a double oven OCXO.
 
  Thanks for any help
  73
  Glenn
  WB4UIV
 
 
  At 06:34 PM 1/24/2009, you wrote:
 
  If that came from a PURC, see if the GPS receiver is included. 
 It may not as
  they used one receiver per site and slaved all the HSO's to it.
  Or, there may be a 14.4 MHz oscillator on board.
  Hopefully the 5 MHz oscillator was not purloined !!
  There are also some jumpers that allow you to set the reference
  input frequency
  (I think, I am only recalling from memory the MSF5000 HSO, which 
 is similar, I
  think).
 
  73, Dick, W1KSZ
 
  -Original Message-
 
  From: Glenn Little WB4UIV glennmaill...@bellsouth.net
  Sent: Jan 24, 2009 4:42 PM
  To: Time-Nuts list time-nuts@febo.com
  Subject: [time-nuts] Motorola KXN1132AA
 
  Recently there was a post about oscillator stability and I thing
  drift over time.
 
  Was the large Motorola oscillator the one in the subject line?
 
  Further markings on the oscillator are source code 9896, Cust No
 
  48R83851N02.
 
  This is a 5 MHz operating frequency oscillator.
 
  There are 8 lugs to interface the oscillator. Pin 4 is plus and pins
  2 and 3 are negative.
  I think that this oscillator is an OCXO and works on 24VDC.
 
  Can this oscillator be disciplined?
 
  What are the other pins for?
  What is the oscillator accuracy?
 
  Thanks
  73
  Glenn
  WB4UIV
 
 
 
 
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[time-nuts] LPRO-101

[Glenn Little WB4UIV]

I have a LPRO-101. Before I power it up, I have been advised to use a heatsink.
How large of a heatsink do I need?
I found an extruded heatsink in the junk box.
This heatsink has fins about 0.50 inches high.
The width is 2.375 inches wide.
It is 8.125 inches long.
I plan to cut this heatsink in half giving me two 4.0 inch pieced.
I plan to bolt each piece to the bottom of the LPRO-101, using the 
six mounting holes, three per heatsink.
Would this be sufficient heatsink?

Thanks in advance.
73
Glenn
WB4UIV



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Re: [time-nuts] LPRO-101

[Glenn Little WB4UIV]

My heatsink appears to have a thermal resistance of about 3 degrees C per watt.
It is similar to Thermalloy 60975.

I will dig deeper into the junk box and see if I can find a heatsink 
with larger fins.

Thanks for the guidance.

73
Glenn
WB4UIV


At 11:50 PM 1/11/2009, you wrote:
Glenn Little WB4UIV wrote:
  I have a LPRO-101. Before I power it up, I have been advised to 
 use a heatsink.
  How large of a heatsink do I need?
  I found an extruded heatsink in the junk box.
  This heatsink has fins about 0.50 inches high.
  The width is 2.375 inches wide.
  It is 8.125 inches long.
  I plan to cut this heatsink in half giving me two 4.0 inch pieced.
  I plan to bolt each piece to the bottom of the LPRO-101, using the
  six mounting holes, three per heatsink.
  Would this be sufficient heatsink?
 
  Thanks in advance.
  73
  Glenn
  WB4UIV
 
 
 
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Glenn

The manual recommends a heat sink with a thermal resistance of 2C/watt
or less for ambient temperatures up to 50C.
Your proposed heatsink may be a little small unless you bow it.

Fin orientation is very important for an non blown heatsink.
If you just attach the heatsink to the base with the fins pointing down
the thermal resistance will be increased significantly over the normal
orientation with convection cooling.

Bruce

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Re: [time-nuts] Another LPRO-101 Rb Osc question...

[Glenn Little WB4UIV]

Note the position of the connector.
This is really a filter plate with leads that also extend into the 
connector on the oscillator.
Remove the two spacer nuts.
Pull the filter plate out.
Remove the cover.

When you reassemble the cover, make sure that you install the filter 
plate correctly.

I would like to know what the other connector is for and what the 
headers inside the oscillator are for.

These are not mentioned in the manual available on the web.

73
Glenn
WB4UIV



At 01:21 PM 1/1/2009, you wrote:
Hello, Time-Nutters--

In looking at the LPRO-101 unit I'm holding in
my grubby little paw, I note that the base of
the case has a thin layer of some sort of
pale-green slippery material glued to it.

Is this the heat-transfer tape/pad mentioned in
the user manual that must be placed on the base
before bolting to a heat-sink?

I notice six threaded insert holes in the bottom
for bolting to a heat sink--  The user's manual
gives mounting screw clearance info for the bottom
plate.  However:

I would like to place a small terminal strip
on the top of the case with an RF connector
and some easy/convenient connection lugs for power
and monitoring, etc.

Question--:  how much clearance is there between
the top of the case and internal components?

It is not clear to me how to remove the top case
section for a look inside to check on component
clearance--

The top cover does not appear to be screwed in place,
but I am reluctant to just try some experimental
prying.  Does the case slide off?  There appear to
be what look like tiny detent-dimples all around
the sides of the upper case lid.  Is this what
retains the upper case in place?  Does it lift off
with very careful prying?

Has anyone done this before?

Thanks--

Mike Baker
WA4HFR
Gainesville, FL



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Re: [time-nuts] Build my own dist. amp ??

[Glenn Little WB4UIV]

With TV stations shifting to digital, how would a surplus analog 
video distribution amplifier do?

There should be a lot of high end amplifiers made by Grass Valley 
(Tektronix) available soon.

These are used in a frame. The input loops through the frame. Each 
amplifier has 6 isolated outputs. Depending on the amplifier, you 
might have control over the equalization or not. All that I have seen 
allow the amplifier gain to be adjusted from the front of the module.

73
Glenn
WB4UIV

At 02:16 PM 12/13/2008, you wrote:
Dave M wrote:
  Randy,
  There are a couple distribution amp projects on the RealHamRadio 
 web site (http://www.realhamradio.com).  One has 8 isolated 75-ohm 
 outputs; the other has 3 non-isolated outputs.  Here are the links to each:
 
  http://www.realhamradio.com/10mhz-video-amp.htm
  http://www.realhamradio.com/g8lmx-amplifier.htm
 
 
Dave, the problem with those, and indeed the TAPR kit eventually, is
that all the Maxim ICs involved have been discontinued, and are no
longer easily sourced.
dr


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Re: [time-nuts] Help with HP 8640B generator

[Glenn Little WB4UIV]

What is the part number of the chip that you need?
Do you have a way to remove the bad chip?
I have a parts board that I could remove the chip that you need from 
and ship it to you. I cannot guarantee that the chip that I have is 
good. If there are two on the board, I could remove both and send then to you.

73
Glenn
WB4UIV

At 11:03 PM 9/4/2008, you wrote:
I've obtained a faulty HP 8640B signal generator, and have determined
that the fault is in one of the dividers. (The unit has output only on
the top two ranges). Other than that, the generator seems to be in fine
fettle.

Since the chance of finding a replacement gold-plated HP-numbered ECL
chip is less than improbable, I'm left with the option of trying to find
a replacement board from another junked generator.

So, does anyone by any chance have a spare divider board from an 8640B,
or a suggestion of how to replace the 64-128MHz divider with something
else?

73,
Murray ZL1BPU


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Re: [time-nuts] 468-DC NBS Time receiver

[Glenn Little WB4UIV]

Thank you for the reply and the links to the resources. I may use 
this as a slave display from another time generator. At least I will 
not waste my time trying to get this to function as it was intended.

Thanks
73
Glenn
WB4UIV

At 12:57 PM 5/28/2008, you wrote:


- Original Message 
From: Glenn Little WB4UIV [EMAIL PROTECTED]
To: Time-Nuts list time-nuts@febo.com
Sent: Monday, May 26, 2008 10:43:26 PM
Subject: [time-nuts] 468-DC NBS Time receiver

I found one of these in my stuff. Is it good for anything but parts?
As I understand it, the service that this received has been shut down.

Thanks
73
Glenn
WB4UIV
Correct no time service, the only other propose I can think of is 
maybe a mod to look at the other data on this channel, Data 
Collection Platform interrogation aka DCPI. Don't know if this 
channel is used all the time as it is reported to interfere with 
another sensor on the sats. And if you are setting up a time musumn...

Link for info: http://rsd.gsfc.nasa.gov/goes/text/databook/section08.pdf
Disconnect notice: http://noaasis.noaa.gov/NOAASIS/ml/nisttime.html
Operating and service manual 468-DC : http://www.to-way.com/468dc.pdf
Info on the Goes Sat : 
http://directory.eoportal.org/presentations/224/7385.html
http://noaasis.noaa.gov/DCS/docs/uim.pdf

Stanley



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[time-nuts] 468-DC NBS Time receiver

[Glenn Little WB4UIV]

I found one of these in my stuff. Is it good for anything but parts? 
As I understand it, the service that this received has been shut down.

Thanks
73
Glenn
WB4UIV




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[time-nuts] Thunderbolt Buy

[Glenn Little WB4UIV]

I would like to be placed on the list for one of these if possible.

Thank you
73
Glenn Little
WB4UIV


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Re: [time-nuts] Robert G8RPI -- Odetics 325 PSU

[Glenn Little WB4UIV]

Roy and the group

SMPS have a very classic failure mode. As the design is finalized by 
a bean counter, and/or the person that designed the SMPS was not 
qualified to do so, we have capacitors pushed beyond what they were 
designed for. If you are lucky, the electrolytic capacitors are 105 
degrees C. If not they are 85 degrees C. In all probability, the 
capacitors are not rated for the service that they are being used .

To fix the supply replace all of the electrolytics with pulse rated, 
105 degree C parts. The SMPS uses high frequency for the energy 
transformation. The designer had to use fast diodes, but, because the 
cheaper capacitors will continue to, somewhat, operate for the period 
of the warranty, the cheaper capacitors are used.

Use the largest capacitor that will fit into the available space. A 
higher voltage capacitor will work fine. If you can measure the 
capacitor ESR, you will find that the ESR has climbed to a higher 
than acceptable level on the capacitors that are causing the problem.

If you check the new capacitors before you install them, you will 
probably find that they are just above the lower tolerance value. If 
the next higher value will fit, use it.

I replace failed electrolytic capacitors almost daily. I am the chief 
engineer at a TV station and see more problems with capacitors than 
anything else. Our equipment is highly abused by being left on 24/7.

Almost all SMPS problem that I have seen are capacitors. Many 
technicians cannot fix a SMPS as they cannot find a bad 
semiconductor and the capacitors will check close to the correct 
value with acceptable leakage. They cannot check the parameter, ESR, 
that is causing the problem.

Hope this helps.

73
Glenn
WB4UIV

At 02:04 PM 4/19/2008, you wrote:
Hi Roy,
   I've looked at two of these PSU's that had failed and was unable 
 to repair either of them. (I'm a professional electronics engineer 
 and can fix most things) There were no obvious faults like leaking 
 capacitors or burnt up components. The topology of the 
 auto-switching between 28V DC  and 115/230V AC is not obvious and 
 the PCB is very densely packed making it very hard to trace the 
 circuit or make measurements. The high voltage on the PCB makes it 
 hazardous to work on. I gave up and replaced them with a standard 
 mains input multi-output unit. I don't recall the voltages and 
 ratings (they were marked on the unit), but if you let me know what 
 they are I'll see if I have a suitable unit. email robert8rpi (at) yahoo.co.uk

   Regards,

   Robert G8RPI.

Roy Phillips [EMAIL PROTECTED] wrote:
   Hi Robert

You may remember that we exchange info on the 325 SatSyc Receivers. 
I remember that you said that the PSU was a weak point with the 
system - you were right on , after finding a suitable antenna and 
replacing the lithium battery in the Rx., it was running sweetly for 
about 18 days, but yesterday it failed. The power fuse (AC input) 
had blown, and following a quick inspection within the PSU - nothing 
appears to be burnt out or visibly damaged. What was your experiece 
of fault finding with this item. Before I proceed further, do you 
have the schematic for the PSU - this is not in the normal manual - 
its an AC to DC, and a DC to DC unit. Its a quality item, Model 
VF100 -494-10/CX ,made by Converter Concepts, and should be worth 
restoration. Any ideas ?

cheers

Roy UP

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-
  Yahoo! for Good helps you make a difference
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[time-nuts] week 1024 roll over

[Glenn Little WB4UIV]

I recently bought a Datum GPS Time/frequency System 9390-5593. When I 
enter date, time and location, it fails to indicate GPS lock. It is 
indicating GPS week 451, when the week is really 1475. It is also 
indicating that the day is 246. I highly suspect that the receiver 
has firmware that needs to be updated.
I have not disassembled the equipment far enough to verify the type 
of GPS engine installed. Does anyone know what GPS engine is 
installed in this equipment?
Will the 1024 week rollover cause the receiver not to lock, I suspect 
that the receiver will not lock as it has incorrect date?
Can I change the engine to something that has correct firmware?
Does the receiver output NMEA 0183 data or something unique?

I contacted Symmetricom as they bought Datum. They say this product 
was out of support prior to them buying Datum. I requested the price 
of a manual. They will sell me one, if they have one to copy, for a 
mere $250.00. I suspect that they do not have a firmware update that 
they will release for a reasonable cost. This is a hobby, not a 
business for me.

Any help or advice? Possibly just scrap this and use the Rb standard?

Thanks
73
Glenn
WB4UIV





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[time-nuts] Datum GPS Time/Frequency System

[Glenn Little WB4UIV]

I am new to the list. I checked the archives, but found no 
information on this equipment.

Does anyone have information on a Datum 9390-5593? I bought one at a 
hamfest and would like to modify it for a 10 MHz out. I suspect that 
I can intercept the Rb standard output with a distribution amplifier 
to feed the original destination and a BNC connector on the back 
panel. The amplifier should isolate the 10 MHz output on the back 
from the reference to the board.

Any help appreciated. What I would like to find is an operators and a 
service manual.

Thank you
Glenn
WB4UIV




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