Re: [time-nuts] accurate 60 hz reference chips/ckts

[Alan Melia]

I dont think working that way would give a stable clock in the UK. Our 
frequency can vary more than the US but the number of cycles between 0800 on 
one day and the next is mandated to be correct (I presume +/- 25 :-))  ). So 
you would be chasing a moving target, and at no time of the day need the 
frequency be 50.000Hz


Alan
G3NYK

- Original Message - 
From: "Jim Harman" 
To: "Discussion of precise time and frequency measurement" 


Sent: Thursday, December 14, 2017 10:08 PM
Subject: Re: [time-nuts] accurate 60 hz reference chips/ckts


Since the power line has the desired long term stability but is poor on 
the

short term, I wonder if a solution might be to use it as the reference for
a "power line disciplined oscillator."

You would want a filter time constant of several hours in the control loop
to smooth out the variations in the 60 Hz.

Or it might be easier to rip the guts out of the Radio Shack clock, just
keeping the display, and drive the display with an Arduino and a DS3231 
RTC

chip as the reference.

On Thu, Dec 14, 2017 at 4:05 PM, Hal Murray  
wrote:




apollo...@gmail.com said:
> Want to provide an accurate  (relatively accurate) 60 hz reference to 
> the

> chip.   Some room inside for custom modifications.  Does a TCXO or
similar
> exist in a small package that provides 60 hz ticks?

I doubt if you will find a TCXO that puts out 60 Hz.  But it's only one
chip
to make a divider.  The trick is to do it in software rather than 
hardware.


The real question is what sort of error pattern are you interested in. 
The

power company has good long term stability.  How good is your TCXO?  It
would
be fun to play with the numbers.  On the other hand, can you derive your 
60

Hz from a GPSDO?

--
These are my opinions.  I hate spam.



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--

--Jim Harman
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Re: [time-nuts] Very large X9.2 solar flare.

[Alan Melia]

They mostly do but the flare is over in minutes and the CME is not visible 
except in any auroral effects unless you run a magnetometer.yes that 
does take 2 days to get here so we get a warning. We are continually seeing 
reports that flares affect the power lines and there is no 
warningmixing up the two events.


Alan
G3NYK

- Original Message - 
From: "David G. McGaw" <david.g.mc...@dartmouth.edu>
To: "Discussion of precise time and frequency measurement" 
<time-nuts@febo.com>

Sent: Wednesday, September 06, 2017 10:46 PM
Subject: Re: [time-nuts] Very large X9.2 solar flare.



It also produced a CME.  Read the note on spaceweather.com.

David N1HAC


On 9/6/17 5:19 PM, Alan Melia wrote:
The flare has been and gone!...is this another case of journalists 
mixing up a flare with a CME ?

Alan
G3NYK

- Original Message - From: "Mark Sims" <hol...@hotmail.com>
To: <time-nuts@febo.com>
Sent: Wednesday, September 06, 2017 8:50 PM
Subject: [time-nuts] Very large X9.2 solar flare.



It might be coming here...

https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.theregister.co.uk%2F2017%2F09%2F06%2Fbiggest_solar_flare_in_years_heading_our_way%2F=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C41d65efbdfcd41b163e708d4f56d6fe6%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C636403297765507567=sv4874WVgjHxh%2Fv94LL%2FQNT3BagNSbdjIG4TC%2FawfvU%3D=0

You might want to break out your eclipse monitoring equipment...
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Re: [time-nuts] Very large X9.2 solar flare.

[Alan Melia]

The flare has been and gone!...is this another case of journalists 
mixing up a flare with a CME ?

Alan
G3NYK

- Original Message - 
From: "Mark Sims" 

To: 
Sent: Wednesday, September 06, 2017 8:50 PM
Subject: [time-nuts] Very large X9.2 solar flare.



It might be coming here...

http://www.theregister.co.uk/2017/09/06/biggest_solar_flare_in_years_heading_our_way/

You might want to break out your eclipse monitoring equipment...
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Re: [time-nuts] Fwd: [hpsdr] SDR experiment for the solar eclipse

[Alan Melia]

Hi John appreciate the problems at HF, and Boulder is very close to the 
track of the totality to use WWVB  Enjoy the event hope you record some 
interesting effects.


Best Wishes
Alan
G3NYK

- Original Message - 
From: "John Ackermann N8UR" <j...@febo.com>

To: <time-nuts@febo.com>
Sent: Thursday, August 03, 2017 9:20 PM
Subject: Re: [time-nuts] Fwd: [hpsdr] SDR experiment for the solar eclipse


That experiment is happening, too.  Folks will be monitoring WWV and CHU 
in narrowband mode with the same tools they use in the frequency measuring 
tests.  (You can't really do direct phase comparisons on HF frequencies 
because between the noise and the ionospheric effects, including doppler 
shift, it's really hard to lock to the RF cycle the way you can at VLF.)


We were originally going to put a 5071A-locked beacon on three ham bands, 
but decided WWV and CHU would be better sources, and logistics were 
turning into a problem: I'm going to be doing my wideband recording from a 
cottage in northern Michigan.  But I'm still a time-nut, so the receiver 
will be GPSDO-controlled, and there will be a stratum 1 NTP server in the 
cottage to provide timestamps. :-)


John

On 08/03/2017 03:57 PM, Alan Melia wrote:
A Time Nut would measure phase change across the path of totality using 
GPS locked SDR receivers :-)) As was done on the Eclipse that passed 
between the UK and Iceland a couple of years ago. Keflavik NRK's 
ionospheric signal was returned from inside the path of totality to most 
of the north of the UK, giving a good measure of the change in height of 
the "apparent reflection height" in the D-layer.


The quoted program looks a bit scattergun..lets record everthing and 
see what's there.
Hopefully it will involve a lot of school kids and maybe interest them in 
science and electronics. If it does that it will be more useful that we 
could imagine.


Alan
G3NYK

- Original Message - From: "John Ackermann N8UR" <j...@febo.com>
To: "Discussion of precise time and frequency measurement" 
<time-nuts@febo.com>

Sent: Thursday, August 03, 2017 8:10 PM
Subject: [time-nuts] Fwd: [hpsdr] SDR experiment for the solar eclipse


This is a little off-topic, but thought some of the group might be 
interested... so please forgive the interruption.


John


 Forwarded Message 
Subject: [hpsdr] SDR experiment for the solar eclipse
Date: Thu, 3 Aug 2017 15:07:57 -0400
From: John Ackermann N8UR <j...@febo.com>
To: fmt-n...@yahoogroups.com, HPSDR list <hp...@lists.openhpsdr.org>

* High Performance Software Defined Radio Discussion List *

I've been working with the "HamSci" group to set up an experiment for 
the solar eclipse: wideband recording of several HF bands before, 
during, and after the eclipse to look for propagation changes (or 
anything else that happens).  All are welcome to participate in the 
experiment, and this is a *perfect* application for our SDRs!


Here's the HamSci web page:
http://hamsci.org/2017-eclipse-hf-wideband-recording-experiment

Various SDRs and programs have wideband recording capability.

Radios that support the HPSDR "old protocol" (which include Hermes-based 
boards as well as the Red Pitaya and possibly others) can do an even 
better trick: they can record multiple slices of the HF band 
simultaneously, thanks to work by Tom McDermott N5EG.


Hermes can do 4 receivers (tested), Mercury/Metis/Atlas systems should 
handle 3 (not tested), and the Red Pitaya can support 6 (tested).  This 
means that we can record most of the 80M band, and all of 40, 30, and 
20M, in one gulp to look for effects of the eclipse -- frequency shift, 
propagation enhancement/reduction, noise floor, etc.


I've written a Gnuradio .grc program that used N5EG's driver to record 
multiple receivers.  By default it's configured for four receivers on 
80/40/30/20M, but that's easy to change.  I'll be posting that software 
to the TAPR github at https://github.com/TAPR as soon as we've done a 
bit more testing.


This software runs on Linux and may work on Windows (I haven't had a 
chance to try, but Gnuradio has been ported to Windows).  Recording 4 
384kHz channels does take some computing horsepower and uses a lot of 
disk space -- about 3MB per receiver per second.  My prior-generation i7 
machine with solid state drive seems to handle it OK.


If you're interested in participating in this experiment, please (a) 
check out the HamSci web page; (b) check the ttps://github.com/TAPR in a 
day or two to grab the software and docs; and (c) feel free to contact 
me directly with any questions.


73,
John N8UR
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Re: [time-nuts] Fwd: [hpsdr] SDR experiment for the solar eclipse

[Alan Melia]

A Time Nut would measure phase change across the path of totality using GPS 
locked SDR receivers :-)) As was done on the Eclipse that passed between the 
UK and Iceland a couple of years ago. Keflavik NRK's ionospheric signal was 
returned from inside the path of totality to most of the north of the UK, 
giving a good measure of the change in height of the "apparent reflection 
height" in the D-layer.


The quoted program looks a bit scattergun..lets record everthing and see 
what's there.
Hopefully it will involve a lot of school kids and maybe interest them in 
science and electronics. If it does that it will be more useful that we 
could imagine.


Alan
G3NYK

- Original Message - 
From: "John Ackermann N8UR" 
To: "Discussion of precise time and frequency measurement" 


Sent: Thursday, August 03, 2017 8:10 PM
Subject: [time-nuts] Fwd: [hpsdr] SDR experiment for the solar eclipse


This is a little off-topic, but thought some of the group might be 
interested... so please forgive the interruption.


John


 Forwarded Message 
Subject: [hpsdr] SDR experiment for the solar eclipse
Date: Thu, 3 Aug 2017 15:07:57 -0400
From: John Ackermann N8UR 
To: fmt-n...@yahoogroups.com, HPSDR list 

* High Performance Software Defined Radio Discussion List *

I've been working with the "HamSci" group to set up an experiment for the 
solar eclipse: wideband recording of several HF bands before, during, and 
after the eclipse to look for propagation changes (or anything else that 
happens).  All are welcome to participate in the experiment, and this is a 
*perfect* application for our SDRs!


Here's the HamSci web page:
http://hamsci.org/2017-eclipse-hf-wideband-recording-experiment

Various SDRs and programs have wideband recording capability.

Radios that support the HPSDR "old protocol" (which include Hermes-based 
boards as well as the Red Pitaya and possibly others) can do an even 
better trick: they can record multiple slices of the HF band 
simultaneously, thanks to work by Tom McDermott N5EG.


Hermes can do 4 receivers (tested), Mercury/Metis/Atlas systems should 
handle 3 (not tested), and the Red Pitaya can support 6 (tested).  This 
means that we can record most of the 80M band, and all of 40, 30, and 20M, 
in one gulp to look for effects of the eclipse -- frequency shift, 
propagation enhancement/reduction, noise floor, etc.


I've written a Gnuradio .grc program that used N5EG's driver to record 
multiple receivers.  By default it's configured for four receivers on 
80/40/30/20M, but that's easy to change.  I'll be posting that software to 
the TAPR github at https://github.com/TAPR as soon as we've done a bit 
more testing.


This software runs on Linux and may work on Windows (I haven't had a 
chance to try, but Gnuradio has been ported to Windows).  Recording 4 
384kHz channels does take some computing horsepower and uses a lot of disk 
space -- about 3MB per receiver per second.  My prior-generation i7 
machine with solid state drive seems to handle it OK.


If you're interested in participating in this experiment, please (a) check 
out the HamSci web page; (b) check the ttps://github.com/TAPR in a day or 
two to grab the software and docs; and (c) feel free to contact me 
directly with any questions.


73,
John N8UR
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Re: [time-nuts] Halcyon OFS

[Alan Melia]

Hi Clint I have had one of these from new. It divides the amplified 
incomming carrier by either 99 or 81 (4526) and phase compares with 2kHz 
from the divided down 10MHz discrete VCXO to phase lock the 10MHz. My unit 
serial number 1151 has no other crystals in it. It possible they are filters 
for the BC carrier frequencies.


Halcyon ceased trading about 10 years ago, I think the PFS that Stephen has 
includes a sythersiser locked to the 10MHz. I never received a manual as 
such merely an A4 sheet printed on one side. I have never even found a 
circuit diagram, despite contacts who knew people that worked there.


Alan
G3NYK

- Original Message - 
From: "Clint Jay" 

To: 
Sent: Monday, June 19, 2017 10:17 AM
Subject: [time-nuts] Halcyon OFS



I have been given a Halcyon Electronics OFS1 standard which seems to work,
it's a version that has 198KHz and 162KHz selector on the fron and after a
reasonable period of time it displays 'lock' and gives a nicely stable 
1,10

and 10 MHz output on the front panel BNCs, (I know, it should be 1,5 and
10MHz out, read on)

Does anyone know of a PDF manual? This version has two KHz crystals inside
it and I'd like to see how/if it's been modified so a manual with a
schematic would be even more useful.



--
Clint.

*No trees were harmed in the sending of this mail. However, a large number
of electrons were greatly inconvenienced.*
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Re: [time-nuts] backfill (was: Poor man's oven)

[Alan Melia]

Hi Bob, it also depends on what you allow to leak into the vacuum. Hydrogen 
is a pretty effective remover of heat :-))

Alan
G3NYK

- Original Message - 
From: "Bob kb8tq" 
To: "Discussion of precise time and frequency measurement" 


Sent: Thursday, June 08, 2017 9:19 PM
Subject: Re: [time-nuts] backfill (was: Poor man's oven)



Hi

If you look at the thermal conductivity vs very low pressures, the 
conductivity

comes up pretty quickly from a hard vacuum. There is essentially no impact
on Q.

Bob


On Jun 8, 2017, at 4:03 PM, Attila Kinali  wrote:

On Thu, 8 Jun 2017 06:55:07 -0400
Bob kb8tq  wrote:

The simple answer is that the backfill is done because it does matter in 
a lot of

cases.


This raises the question, why there is backfill (just for thermal 
conductivity?)

and how much it affects the Q of the crystal.

Attila Kinali


--
You know, the very powerful and the very stupid have one thing in common.
They don't alters their views to fit the facts, they alter the facts to
fit the views, which can be uncomfortable if you happen to be one of the
facts that needs altering.  -- The Doctor
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Re: [time-nuts] Anthorn eLoran

[Alan Melia]

Hi Peter
Ah that sounds more like it. Aerial maintenaance shuts down the whole site 
these dats including MSF.  There is really no reason for them to keep it 
running but I think Trinity House are paying the bill. It cannot be used for 
nav without Lessay and the output from Sylt, So I muse that they are keeping 
it powered up because the equipment is quite old now (1990s vintage, the 
unused kit destined for Loop Head in Ireland) and if the leave it off for 
any length of time it just wont start again :-))  We all know that syndrome 
!


I dont know if this is correct but I got the feeling it was not running 
anything like full power??


Alan
G3NYK

- Original Message - 
From: "Peter Vince" 
To: "Discussion of precise time and frequency measurement" 


Sent: Wednesday, May 10, 2017 4:38 PM
Subject: Re: [time-nuts] Anthorn eLoran



I gather there is an intermittent fault that is taking out a fuse, which
they are, necessarily, working hard to rectify.

Peter


On 10 May 2017 at 10:58, Iain Young  wrote:


On 09/05/17 20:28, moGandalfG8--- via time-nuts wrote:


Iain Young wrote:
I now have all four with green tracking lights, so  looks good to go

Thanks Iain,

Also looking good here now so seems like I cried wolf after all, 
although

very happy it wasn't anything more permanent:-)



I noted this morning, mine were all "Red" again. This very much suggests
antenna maintenance (Off while they work on it during the day, and on
once they've finished the day's work before starting work on it again the
next morning, rather like they do with MSF next door)


Iain


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Re: [time-nuts] Measuring coax temperature coefficient with a TICC

[Alan Melia]

MMmm interesting but what about skindepth ?? surely the "R" is not DC R so 
would it matter? RF currents travelling in the copper anyway.  I suspect 
that a steel inner might increase the L/unit length?, maybe this is more 
significant or not as is sceened by copper??


Alan
G3NYK

- Original Message - 
From: "jimlux" 

To: 
Sent: Wednesday, April 19, 2017 11:17 PM
Subject: Re: [time-nuts] Measuring coax temperature coefficient with a TICC



On 4/19/17 11:57 AM, Hal Murray wrote:


kb...@n1k.org said:
I’d want to be pretty sure what the center conductor was made out of. 
I’ve
seen some stuff in coax that “one would think” should not be there 
(copper

over steel …).


Does that effect the propagation time?

If I gave you a good scope picture of a pulse after going through chunk 
of
coax, could you figure out the ratio of copper to steel?  Would you need 
to

know the length or could you figure that out too?



This being timenuts, I think you might do it with just timing 
measurements.


Let's see - the different candidate materials all have different thermal 
resistance coefficients.  So you can make some DC measurements.  If you 
knew it was some combination of copper and steel, for instance, you could 
probably determine the ratio from that alone (or, for that matter, doing 
it at a single temperature, if you can *measure* the diameter of the 
conductor).


There is some variation in material properties (not all copper is the 
same, and, in particular, steel varies widely depending on alloy and 
manufacturing).




The propagation equation has a dependence on both R and G as well as  L 
and C


Is the change in prop speed due to the change in R bigger or smaller than 
the change due to L and C (from dimensional changes)?


The L and C terms both have a frequency dependent (linear in frequency) 
term.  The R term has a fairly complex dependency on frequency, in terms 
of skin depth relative to the diameter of the conductor.  The G term also 
has a frequency dependence.



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Re: [time-nuts] Bye-Bye Crystals

[Alan Melia]

.and some micro-soldering kit to attach the plated unit to the lead 
frame. Our factory used homemade hot air jets, I have no idea what the 
solder was prob LMP.


Lapping a single blank is difficult, one tends to get rounded edges(even 
with the best machine) which affect the activity. See the video, they are 
lapping several at the same time. The unplated blanks are put into a skelton 
holder and measured and the most promising one proceded with. First an 
evaporated contact to fix the blank to the lead frame. Then electrode 
evaporation which brings the frequency down, so the final stage evaporates 
electrode while measuring the mounted crystal frequency. Allowances need to 
be made for the can.


I doubt most small modern firms would have a X-ray goniometer (?) The one I 
saw in the 60s would never pass H criteria now. They probably buy cut 
blanks in bulk, I think they are relatively cheap this way. My supplier in 
the 90s did this.
The whole job is quite labour intensive, making a single crystal might 
easily eat $1000 worth of manhours for an amateur, not even allowing for the 
occasional "oops".

:-))
Alan
G3NYK
- Original Message - 
From: "Attila Kinali" 
To: "Discussion of precise time and frequency measurement" 


Sent: Monday, March 13, 2017 7:56 PM
Subject: Re: [time-nuts] Bye-Bye Crystals



On Mon, 13 Mar 2017 15:01:39 +
Adrian Godwin  wrote:


What minimal equipment would you need to make your own crystals ?


The equipment is quite minimal:

* A diamond precision saw to cut the crystals
* Some tool to check the accuracy of the cut (orientation and thicknes)
* a lapping/grinding machine
* an electroplating machine (usually sputtering) for the electrodes.
* either some machine to produce the crystal holder yourself or buy them
* vacuum system to evacuate the crystal holder and to bake everything
* something to (cold) weld the case close


All of this can be put in a (relatively) small workshop.
The difficulty is also not producing quartz crystals
in holders. The difficulty controlling the whole process
to such an degree that you get high quality crystals
at the frequency you want.

If you managed to do that, you can further improve
your system by using a BVA[1,2] like geometry, where
the electrodes are not on the resonator itself but
on the surrounding crystal, which acts at the same
time as holder.
But be warned, many attempted to re-create the BVAs
but few succeeded... and none but Oscilloquartz ever
managed to produce a economically viable product.


Attila Kinali

[1] http://www.nature.com/articles/srep02132/figures/1
[2] http://www.nature.com/articles/srep02132/figures/2

--
It is upon moral qualities that a society is ultimately founded. All
the prosperity and technological sophistication in the world is of no
use without that foundation.
-- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] RFDO - Experience and questions

[Alan Melia]

Paul the off-air standards I have and another UK make I dont posses divide 
the 10MHz standard and the off-air carrier down to 2kHz for locking. It may 
not be the best but it is generally adequate for off air LF standard 
distribution. My unit will cover 162kHz or 198kHz.


Alan
G3NYK

- Original Message - 
From: "paul swed" 
To: "Discussion of precise time and frequency measurement" 


Sent: Tuesday, March 07, 2017 5:52 PM
Subject: Re: [time-nuts] RFDO - Experience and questions



Gilles
I went back over the starting thread and believe your home brew oscillator
may prevent you from getting all of the accuracy out of TDF.
As I was thinking about a TRF radio and locking the question I arrived at
is how do you turn 162KHz into something useful like 100 KHz 5 MHz or 10
MHz??.
By getting to standard references there are many very good oven 
oscillators

available.
Regards
Paul.

On Mon, Mar 6, 2017 at 10:35 PM, paul swed  wrote:


Actually as I think about it from the earlier part of the thread. Locking
to the carrier with a 2-4 second time constant removes the phase 
modulation
since its only in the first 200 ms. The 0 Phase is 800 ms in length or 
more

for all bits.
Now to find some nice coils for 162 KHz.
Regards
Paul

On Mon, Mar 6, 2017 at 8:30 PM, paul swed  wrote:


A bit more reading if you block the phase comparison from -50ms to 150ms
of the tick you get a 0 carrier phase no modulation. That also explains 
why

I thought I could here some sort of phase modulation because there is.
So as an example if you use a GPS tick its really simple to block the
phase changes and only measure the 0 phase carrier. Essentially a 200 ms
carrier gap per second.
Thats quite a clean format you have to work with.
Regards
Paul
WB8TSL


On Mon, Mar 6, 2017 at 8:19 PM, paul swed  wrote:

I checked out 162KHz at 2000 local and now have what I believe to be 
TDF
using the 67 ft vertical antenna. I am reading -82 dbm near Boston in 
the

US or 3400 miles. A comfortable signal at least in the winter. As a
comparison wwvb at 60 KHz is -77dbm some 2000 miles but also not at a 2 
MW

power level like TDF.

Since I had not heard TDF before I listened to Pieters online SDR radio
to see what to listen for. The easiest point to notice is the 59 second
phase. Its funny that also seconds 0-10 should be the same phase but it 
did
not seem to be true. Unless what I am hearing is the local oscillator 
of

Pieters SDR radio.

So thanks for sharing some new knowledge with Time-nuts.
Regards
Paul
WB8TSL

On Mon, Mar 6, 2017 at 1:46 PM, Pieter-Tjerk de Boer <
ptdeb...@cs.utwente.nl> wrote:



On Sun, Mar 05, 2017 at 10:42:52PM +, Iain Young wrote:

> That's TDF from France. Their equivalent of WWV/MSF/DCF.

> Average phase and frequency deviation is
> zero over 200msec (see link above for details)

This is not quite correct, since the transmitter does not just carry 
the

time data (one bit per second, in the first 200 ms of the second), but
also some more data during the next 700 ms of each second.
The latter data is coded in a way which does not guarantee that the
phase
or frequency average is zero other than when averaging over the entire
700 ms block.
Then again, I've been told that although there is a nicely defined
framing
format, in reality it has only ever transmitted idle frames, so in
practice
it's a fixed pattern which repeats every minute and thus could be
cancelled
for use as a frequency reference.

I have a live online decoder for TDF's signal at
   http://websdr.ewi.utwente.nl:8901/tdf/

Regards,
  Pieter-Tjerk, PA3FWM

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Re: [time-nuts] Vintage Frequency Measurement

[Alan Melia]

Hi Dan yes that is 5e-6 about all an unstabilised (temp) AT could hold for 
any period. I guess there were no WWV or MSF signals around then. When a 
good source was available off-air it was possible to do better than that. In 
service it was probably "dont waste time trying to better the minimum 
requirement. The transmitter you are looking for wont be that accurate or 
stable"


In 1960s I saw several BC-221s in the racks at the Rugby LF and HF stations 
acting as standby frequency sources (VFO) for rapidly running up a 
transmitter on an unusual frequency (not a normal route) for which they did 
not have a crystal available.


Alan
G3NYK
- Original Message - 
From: "Dan Rae" 
To: "Discussion of precise time and frequency measurement" 


Sent: Sunday, February 12, 2017 11:11 PM
Subject: Re: [time-nuts] Vintage Frequency Measurement


To put BC-221 things in perspective, the 1 Mc/s reference crystal was 
adjusted, according to the manual, to within 5 c/s...


Things have come a ways since!

Dan


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Re: [time-nuts] Vintage Frequency Measurement

[Alan Melia]

I am surprised no-one mention the 3-beat method, which was fairly common for 
Hams with comms receivers. You put the BFO on and adjusted so the main slow 
beat modulated the level of the output tone. You can judge zero beat to much 
better than 0.1Hz that way probably near as low as 0.01Hz. (1E-9 for 10MHz 
!!)


Lissajous figures are not ideal either but don't require a comms receiver, 
(but do require a 'scope with X-Y facilities :-))  ) a better technique 
certainly for fixed frequencies (stand comparison) uses Z-mod on the scope 
or a running "toothed wheel" display see Radio Laboratory Handbook by 
Scroggie.


Ah and the BC-221..

Alan
G3NYK



- Original Message - 
From: "Bob Albert via time-nuts" 
To: "Discussion of precise time and frequency measurement" 


Sent: Sunday, February 12, 2017 5:00 PM
Subject: Re: [time-nuts] Vintage Frequency Measurement


First you need a standard, a crystal oscillator. If you want serious 
precision, you'd have one in an oven. Zero beat that with WWV. Then make a 
very stable VFO and calibrate the harmonics against the crystal. Assume 
linear calibration on the VFO between check points.
The military LM and BC-221 were very good units. I had one. The check 
points in the calibration book were too far apart but there were others 
that weren't documented that would make for more precise calibration.
I also built a frequency meter that was amazingly accurate, from a GE Ham 
News project printed back in the early 1950s. It used a VFO that went 
between 100 kHz and 101 kHz for its full range, adjusted by a micrometer 
dial (military surplus). Its harmonics would be zero beat with the 
unknown. Using a successive number of harmonics would identify the 
harmonic number and the scale could be interpolated to within much less 
than 1 kHz over the HF range.
Of course, zero beat was hard to identify so you could use an oscilloscope 
lissajous pattern (if you had an oscilloscope, which I didn't). What I did 
was turn up the volume and listen to the beat. When it got down near zero 
the sound of the AGC surging would tell me the frequency of the beat and I 
could adjust to make it stop surging.

When I got my hands on a Beckman counter I was in heaven.
Bob


   On Sunday, February 12, 2017 4:01 AM, Neville Michie 
 wrote:



Back in the early sixties I worked in a lab adjusting filters for line 
transmission.
We had numerous oscillators, built to be boat anchors, and CROs set up for 
X-Y display.

The lab had 100hz, 1kHz, 10kHz standards wired in.
We were expert at recognising lisajou figures. We might have several 
oscillators running together,

and we could establish almost any frequency with precision.
Calibting an oscillator would not have been difficult.

Cheers, Neville Michie



On 12 Feb 2017, at 5:08 PM, Scott Stobbe  
wrote:


I was inspired recently coming across a Lampkin 105 frequency meter, as 
to

how frequency measurement was done before counters.

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


Is there a standout methodology or instrument predating counters?
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Re: [time-nuts] Something odd - ionosphere?

[Alan Melia]

I doubt that was the cause. The stream was high velocity but low density, 
The geomagnetic activity has been relatively low with little precipitation. 
Th Kp has touched 4 but that is not unusual and what you report seems an 
unusual event.  NOAA data is more reliable than Spaceweather which tends to 
overhype Solar events in my experience. TheDst index has hardly changed over 
the last 6 days.


If no one else reports a glitch.Do you need to look closer to home??

Alan
G3NYK

- Original Message - 
From: "Graham" 

To: 
Sent: Sunday, January 08, 2017 10:17 PM
Subject: Re: [time-nuts] Something odd - ionosphere?




*SOLAR WIND SURROUNDS EARTH:*For the fifth day in a row, Earth is 
surrounded by a fast-moving stream of solar wind flowing froma large hole 
in 
the sun's atmosphere. NOAA forecasters say there is a 40% chance of 
G1-class geomagnetic storms on Jan. 8th asbright auroras 
flicker around the 
Arctic Circle.


http://spaceweather.com/  for further details

cheers, Graham ve3gtc

On 2017-01-08 20:48, Bob Stewart wrote:
This morning at about 0400 CST and again at more or less 0800CST, I 
noticed a number of large phase excursions on one of the GPSDOs I'm 
testing.  It also happened the day before but I didn't notice the time. 
I am comparing the 1PPS from two separate units on a 5370.  On the one 
unit I was logging, there were 2 or three phase excursions of up to +/- 
28ns or so at these times.  And yet, the 5370 showed nothing out of the 
ordinary on the plot of the phase difference between the two units.  So 
that tells me that it happened to both GPSDOs.


Did anyone else see anything odd in whatever units you're logging at 
around this timeframe?  Was this likely caused by an ionospheric shift?


Unfortunately, I didn't save the data for any of that, as I was only 
logging one of the units.  Now I'm logging both units in question, as 
well as the Timelab data, and of course it probably won't happen again.

Bob
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Re: [time-nuts] Vintage Quartz Crystal Manufacturing

[Alan Melia]

Hi agn Adrian .quote from Wireless for the Warrior

"Wireless Set No. 7 was a mobile transmitter/receiver developed in 1935. 
Use: communication between tanks. Frequency range 1.875-5MHz. MO/crystal 
control. RF output 5W. R/T and MCW. Range 3-5 miles. Unusual shape to fit in 
the bulge of a tank. Only a limited number were produced. Replaced by No. 9 
set."


Alan
G3NYK


- Original Message - 
From: "Adrian Godwin" 
To: "Discussion of precise time and frequency measurement" 


Sent: Saturday, November 26, 2016 12:40 PM
Subject: Re: [time-nuts] Vintage Quartz Crystal Manufacturing



I bought some old crystals on ebay :

http://www.ebay.co.uk/itm/15114483

Is anyone familiar with this style ? I don't think the quartz is visible 
in

the glass section : I imagine that's just an insulator. I think the quartz
is under a brass disc, with a sping to hold the disc down visible through
the glass.

Does anyone know what the reference marked on them "w'less sets No 7"
refers to ?


On Mon, Sep 26, 2016 at 6:50 AM, Mark Sims  wrote:


Can you say "Mr Rogers' Neighborhood?"   I knew you could...

He (along with creepy Mr McFeelie) always ran segments on how some item
was made.   Geared towards pre-schoolers, but always worth watching.

-

Compare the Science channel's new "How Do They Do It" to the older "How
It's Made"
shows.
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Re: [time-nuts] Vintage Quartz Crystal Manufacturing

[Alan Melia]

Hi Adrian (in the UK I think) I think you will find the designation WS.7 is 
a UK Military type number. Try and search vintage military radio.
Lovely beasties, I have not seen that configuration and they are probably 
quite early in the use of quartz in sets on a manufacturing scale


BestWishes
Alan
G3NYK

- Original Message - 
From: "Adrian Godwin" 
To: "Discussion of precise time and frequency measurement" 


Sent: Saturday, November 26, 2016 12:40 PM
Subject: Re: [time-nuts] Vintage Quartz Crystal Manufacturing



I bought some old crystals on ebay :

http://www.ebay.co.uk/itm/15114483

Is anyone familiar with this style ? I don't think the quartz is visible 
in

the glass section : I imagine that's just an insulator. I think the quartz
is under a brass disc, with a sping to hold the disc down visible through
the glass.

Does anyone know what the reference marked on them "w'less sets No 7"
refers to ?


On Mon, Sep 26, 2016 at 6:50 AM, Mark Sims  wrote:


Can you say "Mr Rogers' Neighborhood?"   I knew you could...

He (along with creepy Mr McFeelie) always ran segments on how some item
was made.   Geared towards pre-schoolers, but always worth watching.

-

Compare the Science channel's new "How Do They Do It" to the older "How
It's Made"
shows.
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Re: [time-nuts] Rohde & Schwarz XSD 2.5 MHz crystal gone bad?

[Alan Melia]

Michael a couple of wild thoughts, make sure there is no 500kHz there (this 
is the crystal fundamental and the maintaining circuit should be 
degenerative there. (Is it a Meecham Bridge?)


That sounds like a baseless IO GT valve (tube in US ) enclosure which was 
probably originally evacuatedhas the vacuum gone soft in 50 years?I 
dont know how you would check, but I think that would cause a lowering of 
the frequency.


Alan
G3NYK

- Original Message - 
From: "Michael Ulbrich" 

To: "Time-Nuts" 
Sent: Sunday, November 20, 2016 11:49 PM
Subject: [time-nuts] Rohde & Schwarz XSD 2.5 MHz crystal gone bad?



Hi there,

I'm new to this list and have some interest in quartz crystal and
rubidium oscillators - GPS, NTP, PPS and "clock watching" in general ;-)

I snatched an R XSD frequency standard accompanied by an XKE frequency
controller. Found the manuals on KO4BB's site (Thanks a lot for that!
BTW there's a slight mix-up of pages in that some of the XKE pages have
found their way into the XSD manual).

My initial hope of a quick and easy restoration project faded a bit when
I looked at the XSD output frequency after heating up the oven. It was
off by about -1 * 10-5 and after cranking the fine tuning for some time
and having another look at the specs I realized that the frequency was
too far off to be dialed in by the fine tuning which only covers about
+/- 2 * 10-7.

Next step was to take apart the oven and check series capacitor,
oscillator and the crystal itself. I found that even the coarse
adjustment range of the cylindrical series capacitor (40 - 110 pF) would
not allow to pull the crystal to it's specified frequency. When
replacing the series cap by a ceramic and lowering the value to just
before the oscillation breaks down (about 10 pF) I managed to set the
oscillator frequency offset to  +2.5 * 10-6 at room temperature. But
even this will not suffice when taking into account that the frequency
will drop by a few parts in 10-5 (cf. XSD manual) when the oven heats up
to its operating temperature. I also checked some of the components on
the oscillator PCB which might have an influence on frequency but could
not find any fault.

The crystal itself is a disk of about 30 mm diameter mounted in a sealed
glass cylinder of about 38 mm dia. and 43 mm height. There is no socket
just 2 bare wires.. It does not show any visual signs of damage.
According to a reference given in the R XSD manual the crystal's
construction follows a publication from A.W. Warner "Design and
Performance of Ultraprecise 2.5-mc Quartz Crystal Units" in Vol 39,
Issue 5 of Bell Labs Technical Journal (Sept. 1960). According to that
it is an AT-cut 5th overtone design.

Now my questions:

a) Considering that this gear is about 50 years old, a "crystal gone
bad" situation shouldn't be that much of a surprise, right?  But could
there be any other cause of the "huge" frequency offset besides a bad
crystal? I would very much appreciate any idea that I could try to get
this baby back on spec.

b) if nothing else helps: Could any of you give me a hint about who
might be able to supply a spare crystal? I tried my directly reachable
contacts but unfortunately to no avail so far. Please consider that
similar crystals might also have found their way into other
manufacturer's constructions from that era - Sulzer, Racal, HP ... you
name it ...

Many thanks in advance!

Best regards ... Michael U.
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Re: [time-nuts] For those that insist on using switching power supplies

[Alan Melia]

.but can you listen to the radio in the car ??  Many of these things 
will kill other applications like broadband over twisted pair and PLT tv 
extension. Never mind killing you!

Alan
G3NYK
- Original Message - 
From: "Van Horn, David" 
To: "Discussion of precise time and frequency measurement" 


Sent: Thursday, October 13, 2016 2:05 PM
Subject: Re: [time-nuts] For those that insist on using switching power 
supplies



To be fair here, phone chargers have almost no requirement to be quiet 
other than conducted and radiated emissions limits.

It's charging a battery.

As a designer of some fairly quiet SMPS systems, this feels like "look how 
bad a family car this tractor is".


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Re: [time-nuts] Prologix USB-GPIB Controller

[Alan Melia]

There is another way to those possible Dave Kirby quotes.remember 
silicon foundry lines run lots of wafers through the fab line at one time 
these are tested automatically and inked at the end of the process and put 
inro store. The wafer are drawn and cut and encapsulated (sometime halfway 
round the world from the fab line) when required. It being possible that 
high yeilding wafers are drawn first. It is possible low yeilding wafers my 
be returned to the silicon refiner to use as material for a new batch of 
rods (boule). These may be intercepted or bought by a small company for whom 
it is worthwhile to bond up chip from low yield wafers. On the other hand 
they could wash off the ink (testfail marker) and bond up the lot making 
money out of known duds that look genuine if opened (difficult with plastic 
encapsulation, without damaging the chip metallisation) I have bought old 
3inch wafer in the past on eBay to use as lecture samples. They had a 
genuine looking device on them but no id.


Alan
G3NYK

- Original Message - 
From: "Alexander Pummer" 
To: "Discussion of precise time and frequency measurement" 


Sent: Monday, October 10, 2016 6:28 PM
Subject: Re: [time-nuts] Prologix USB-GPIB Controller


Once upon the time I designed some power-supplies, used parts from a sound 
name US company, they asked for $12.-- each  --it was long time ego -- the 
equipment supposed to built in Asia, the manager -- I was one outside 
consultant -- told me that we can not use that expensive parts, my Chinese 
colleague told, that I should not worry that part will not cost more than 
a dollar, at the end we got the parts for 57 cents in Hong Kong,  the 
manager was on the opinion that the cheap parts are counterfeit, therefore 
we opened  one expensive original and one cheap one; the silicon was 
identical, as the performance toowas it a perfect copy, or one 
original?, who cares it worked like the original, but much cheaper.


73
KL6UHN
Alex

On 10/10/2016 10:13 AM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote:

On 10 October 2016 at 09:35, Charles Steinmetz 
wrote:


Poul-Henning wrote:

And for voltage references, "pre-owned" is likely to mean "better".
Perhaps, but third-world recyclers are not known for gentle treatment
during the parts removal process.


I had some cheap ($10) GPS receiver boards shipped to me in a plastic
kitchen bag from yikunhk on eBay. 4 boards in the same bag, all 
scratching

each other. The bag was not anti-static.

There are all number of possible explanations of why boards can be made 
so

cheaply, when the ICs appear to cost more than the boards.

* The chips are counterfeit
* The chips are similar to what they are supposed to be, but have been
relabeled.
* They are made at the same factory as the real devices, on what I've 
heard
described as the "ghost shift", where they are not officially made, but 
are

the same devices.
* They are recycled.
* They are stolen.

It is anyone's guess once you start buying semiconductor devices from 
eBay.

Maybe you are lucky, maybe you are not.

You dramatically increase the probability a part is good if sourced from 
a

reputable source (e.g. RS or Farnell in the UK). That is not to say that
the parts are not counterfeits, as even the best suppliers can get 
caught,

but they are more likely to be ok.

I recently bought a supposedly original Samsung battery for my Samsung
Galazy S3 phone from a local shop. The phone had all sorts of issues with
this battery, so I concluded it was a poor counterfeit.  I thought I'd be
safe buying directory from Amazon (not a 3rd party), but on reading 
reviews
on Amazon, I was not convinced those were genuine Samsung batteries 
either,

so I did not buy from Amazon.

Eventually I bought a battery from the Samsung website. The phone now 
works
ok.  I don't know if  Samsung actually make the batteries themselves, but 
I

think I have a better chance of buying from the Samsung website than from
anywhere else.

I've had "Duracell" batteries leak. At one time I used to blame Duracell,
but now it has cross my mind whether they might have been bought on eBay
and were counterfeits. I can't recall where they were purchased, but now 
I

will only purchase batteries from sources I consider reputable.

Dave.
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-
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2016.0.7797 / Virus Database: 4656/13182 - Release Date: 
10/10/16


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Re: [time-nuts] OXCO Spurious Output at Line Frequencies

[Alan Melia]

Bob the VLF guys in Europe can receive the 60Hz signal over here! so you 
probably needed a test site on the far side of the Moon :-))

Alan
G3NYK

- Original Message - 
From: "Bob Camp" 
To: "Discussion of precise time and frequency measurement" 


Sent: Tuesday, July 12, 2016 10:53 PM
Subject: Re: [time-nuts] OXCO Spurious Output at Line Frequencies



Hi

The “practical” solution often is to ship it to an office of the same 
company that happens
to have 60 Hz power. The spur moves to 60 / 120 / 180 and they move on 
with their

evaluation.

I have also played the “let’s do it with batteries" approach. Screen rooms 
were of little benefit.
Simply running test gear on batteries did not do the job. Ultimately we 
wound up in the
middle of an Illinois corn field with a bunch of gear modified to run 
purely on batteries. The
spur did go down, but it never fully went away.  It’s been 40 years since 
that adventure so I

really could not say just how far down we got it ….

Anything past -120 db at line frequency is in the “don’t bother” category.

Bob



On Jul 12, 2016, at 6:44 AM, Martyn Smith  wrote:

Hello,

I have a customer who is measuring the phase noise of my 10 MHz ultra-low 
phase noise frequency standard.


He is seeing spurious signals at line frequencies (50 and 100 Hz as we 
are in Europe) at a level around -130 dBc.


My opinion is that it's impossible to get much better than that.  Even 
running on batteries make little difference, since the equipment is in a 
test rack with AC signals everywhere.


Even the £50k R test set he is using only quotes a spurious spec of -90 
dBc.


What experience does anyone have here?

Best Regards

Martyn


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Re: [time-nuts] Visiting Greenwich

[Alan Melia]

Hi Clint I think when I discussed this last a few years ago with the 
speaking clock designer and David Rooney the man responsible for the time 
gallery at Greenwich. The clock is an early quartz unit, probably made at 
the then Post Office Reseach Labs at Dollis Hill in NW London.  The clock is 
quite a beast ! It was found in a skip (Dumpster) having been donated to a 
university in the late 1940s, and was refurbished by a local enthusiast for 
David. He did a good job because I believe he had no access to any documents 
or circuits. I tried to find some information but it would seem the archive 
has been lost (vandals !!) It probably contains strange things like neon 
ring counters :-))


Alan
G3NYK

- Original Message - 
From: "Clint Jay" 
To: "Discussion of precise time and frequency measurement" 


Sent: Tuesday, July 05, 2016 9:13 PM
Subject: Re: [time-nuts] Visiting Greenwich



They also have TIM the speaking clock which has a rack mounted  atomic
standard.
On 5 Jul 2016 21:01, "John Dalziel - crashposition" 


wrote:

I would also recommend the Worshipful Company of Clockmakers collection 
at

the Science Museum. It’s a great collection and they have some of
Harrison's wooden long case clocks as well as his final chronometer, H5.


http://www.sciencemuseum.org.uk/visitmuseum/plan_your_visit/exhibitions/clockmakers-museum


John Dalziel
computus.org


Message: 4
Date: Mon, 4 Jul 2016 18:31:35 -0400
From: Dave Martindale 
To: Discussion of precise time and frequency measurement

Subject: [time-nuts] Visiting Greenwich
Message-ID:

Content-Type: text/plain; charset=UTF-8

I am in London England at the moment, playing tourist with the rest of my
family. I want one day to be a visit to the National Maritime Museum at
Greenwich, which includes the Royal Observatory Greenwich. I am
particularly interested in seeing Harrison's H1 through H4, plus other
high-precision mechanical timekeepers (pendulum clocks, etc).

I know they are at the NMM - their web site shows some of them. But where
are they located on the site? The NMM has a large main building down near
the Thames, while the Royal Observatory and related buildings are on the
top of a hill further inland in Greenwich Park. Are the chronometers and
other precision timekeepers on display somewhere in the Royal 
Observatory,

or down in the main NMM building? I've spent an hour or two browsing web
sites without finding this particular bit of information.

I figure there must be list members who have visited the NMM, and know
where the precision timekeepers are actually displayed.

Thanks,
Dave
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Re: [time-nuts] Measuring receiver...

[Alan Melia]

TX "fingerprinting" in WWII
You seem to be forgetting that there were very few of the sophisticated 
digital timing systems were available 75 years ago. Traffic analysis was 
started early in 1938 or even before. By 1939 we knew all the nets used in 
Europe and had "Y" ( a corruption of WI, Wireless Intercept )operators 
monitoring the nets. Many of these were amateurs and they were allocated to 
specific nets and followed them around as they moved. They became very 
familiar with the "accents" of operators on their nets, and particularly 
before 1939 security procedures were very lax and "chatting" 
common-place.but it was all aural.


I suspect serious transmitter parameter logging was not done before the cold 
war when spectrum analysers, or at least pan-adapters became more readily 
available. To keep a little OnTopic .you would have difficulty doing 
this with a BC-221.!! :-)) A crystal clock of this period was at least one 
fully utilised 6foot 19inch rack (there is one at Grenwich.)

Alan
G3NYK


Alan
G3NYK

- Original Message - 
From: "jimlux" 

To: 
Sent: Tuesday, June 21, 2016 10:02 PM
Subject: Re: [time-nuts] Measuring receiver...



On 6/21/16 11:28 AM, Brooke Clarke wrote:

Hi:

During W.W.II there were secret methods of "fingerprinting" radio
transmitters and separately the operators.
I suspect the transmitter fingerprinting involved things like frequency
accuracy, stability, CW rise and decay time,  For the operator some
from of statistics on the timings associated with sending Morse Code.
But. . .  I haven't seen any papers describing this.  Can anyone point
me to a paper on this?

For "human controlled" stuff, e.g. recognizing someone's "fist", there's a 
huge literature out there on biometric identification looking at things 
like keyboard and mouse click timing - the timing requirements are pretty 
slack, and hardly time-nuts level, unless you're looking to do it with 
mechanical devices constructed from spare twigs and strands of kelp.


There have been a variety of schemes for recognizing individual radios by 
looking at the frequency vs time as they start up. Likewise, it's pretty 
easy to distinguish radar magnetrons from each other.  Not a lot of papers 
about this, but you'll see it in advertising literature, or occasionally 
in conference pubs (although I can't think of any off hand).  There was 
someone selling a repeater access control system that was based on the 
transmitter fingerprint.


But the real reason why you don't see any publications is that this stuff 
is pretty classic signals intelligence (SIGINT or MASINT) and it is still 
being used, and is all classified. You're not relying on Betty the 
receiver operator to recognize the characteristic chirp as the agent's 
radio is keyed, it's all done by computer now, but the basic idea is the 
same.  And as with most of this stuff, the basics are well known, but the 
practical details are not, or, at least, are the proprietary secret sauce 
in any practical system. (In a significant understatement, Dixon, in 
"Spread Spectrum Systems" makes some comment about how synch acquisition 
is the difficult part and won't be described in the book)


You might look at the unclassified proceedings of conferences like MILCOM 
and find something.  Googling with MASINT might also help.


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Re: [time-nuts] MSF 60KHz Problems?

[Alan Melia]

Hi Nigel its been running about 17msecs fast for that last couple of months 
but it seemed to be corrected last week, maybe the exciter failed completely 
:-))  Gotta be all this snow you have been getting !!


Best Wishes
Alan
G3NYK


- Original Message - 
From: "GandalfG8--- via time-nuts" 

To: 
Sent: Tuesday, May 03, 2016 3:15 PM
Subject: [time-nuts] MSF 60KHz Problems?



Is anyone else seeing anthing unusual with the MSF 60KHz signal from
Anthorn?

For the past 24 hours or so, at least, all I've been monitoring here,
approx 100 miles from Anthorn, is what seems to be a much weaker than 
usual
carrier that's pulsing at significantly faster than once per second. It's 
weak

enough that I wondered at first if it  possibly wasn't even MSF but
something else on the same  frequency.

There's no scheduled maintenance in my diary and I haven't been able to
find reference online to any problems, my first concern was that it  might 
be

an antenna problem but the Anthorn eLoran signals on 100KHz seem to  be
coming in fine on the same antenna.

What's really odd though is that several minutes ago I powered up  an EES
MSF clock from that same antenna feed and this has now  synchronised and 
is

displaying the correct time.

Regards

Nigel
GM8PZR
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Re: [time-nuts] Fast risetime pulse generator

[Alan Melia]

Bill, Avalanche pulse gens only require high voltage because of the high 
VBRcbo and the gain of normal NPN transistors. I cant find the reference now 
it might have been a 1970s Ham Radio but if you use the same circuit as Jim 
but put an NPN "upside down" that is emitter where the collector is in Jim's 
circuit you can fire off fast pulses from a 12v supply, instead of requiring 
70 to 100v. I do wish I could locate the source as I have had several 
arguments about it :-))in the nicest possible way of course.


Alan
G3NYK

- Original Message - 
From: "BIll Ezell" 

To: 
Sent: Tuesday, April 12, 2016 9:30 PM
Subject: [time-nuts] Fast risetime pulse generator



(cross-posted to volt-nuts)
After paying only limited attention to this topic, I suddenly have a need 
for a pulse generator that has <150 ps risetime and a pulse width of at 
least 2 ns. 100mv amplitude or more is fine. I've looked at the classic 
Jim Williams avalanche generator, but I don't want to have to deal with 
the (relatively) high voltage source needed.


I've done microwave design using Gunn diodes, so I'm drawn to using a 
step-recovery diode. The topology seems very straightforward, and I can 
build it right onto a BNC connector, no PCB.


I'm thinking using an SMD835 diode, biased at ~1ma. The (sketchy) 
datasheet claims a T of 20 nsecs and a Tr of 85 ps, Cj of 0.4 to 0.8 pf.


Questions:

The obvious, is it reasonable?

Is the bias current reasonable? I'm assuming the bias current is actually 
dependent on the repetition rate, you need enough current to replenish the 
charge within one pulse cycle. I suppose I could compute it from the 
stated junction capacitance, but I'm not sure that's the only factor.


Will the stored charge actually give me the desired transition rate into 
50 ohms? Hmm, again I should be able to compute this, but any other 
factors ignoring the non-diode ones like cap inductance?


How should I compute the coupling cap from the diode to the load? Use the 
impedance at the pulse rep rate? Seems reasonable. BTW, I don't care about 
droop in the  pulse, just the risetime.  (measuring overshoot in an HF 
amp). Again, just want to verify that the obvious answer is the correct 
one. I clearly need to be very careful about the inductance.


Thanks, Bill

--
Bill Ezell
--
The day Microsoft makes something that doesn't suck
will be the day they make vacuum cleaners.
Or maybe Windows 10.

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Re: [time-nuts] Reliability of atomic clocks

[Alan Melia]

Hi Attila, I am out of the business now, well retired, so my opinion carries 
little weight,
:-)) but for whatever it does, my thought is that MTBF is a pretty useless 
parameter in general. This is a relatively low volume unit manufactured by a 
variety of different firms with each their opinion on the best optimum.


The statistical base to MTBF is faulty and in my opinion its only use is to 
indicate where a design might be improved by changing the component mix. The 
actual value that falls out of the end of the calculation for a desgn is 
completely meaningless, but the non-tech bean-counters wanted a way to 
justify more expensive designs, and the purchase of expensive kit.


I would doubt that anyone collected the data on completed units, though 
there may have been spec values quoted. I guess in this usage area most used 
expected them to fail and guarded against it by duplication, the exception 
may be the space environment but I have no experience there.


Good Luck with it
Alan
G3NYK

- Original Message - 
From: "Attila Kinali" 

To: 
Sent: Sunday, March 27, 2016 12:53 PM
Subject: [time-nuts] Reliability of atomic clocks



Moin,

Maybe someone here can help me.
I am looking for data on the reliability of atomic clocks.
I.e. how often and, if possible, how they fail.

Unfortunately, if I google for reliability then all that pops up
are descriptions of the accuracy and stability of atomic clocks.
If I go for MTBF I only get two papers from the 70s that tackle
the problem in general, without giving any data.

Does someone know where I could find current data about MTBF and
failure modes of atomic clocks? Given the number of 5071's installed
in labs, there must be at least some data on them


Attila Kinali

--
Reading can seriously damage your ignorance.
-- unknown
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Re: [time-nuts] Glass Envelope Quartz Crystals

[Alan Melia]

I think it was unlikely that that it was made "just to see where it would
come out" That is a flexural bar possibly an NT cut. 100KHz standards were
commonly made in this format.
The British GPO had a factory at Mill Hill in N. London making these in
tube-like (valve in UK) enclosures, IO GT and B7G. I have a number of unit
saved from the dumpster (skip in the UK).when the unit closed in the early
60s. Remember there was a surge in telephones in this era and many of these
frequencies were for FDM carriers on trunk sytems. This is pre-synthersiser.

Also many special quality tubes were made for VHF in B7G with two or three 
inch wires instead of pins to reduce the socket parasitics. so these were 
probably still around in Russian factories to produce  components for the 
"Foxbat" etc.


Alan
G3NYK


- Original Message - 
From: "Philip Gladstone" 

To: 
Sent: Wednesday, February 03, 2016 1:21 PM
Subject: Re: [time-nuts] Glass Envelope Quartz Crystals



I dug around in my junk box, and found this:

https://plus.google.com/+PhilipGladstone/posts/JBNLMSq2rsE?pid=6247050011623528018=115465617973526125523

This is (according to the markings) a 71.137 kHz crystal made in 1948. I
suspect that they just measured the crystal after manufacture rather than
actually trying to make a 71137Hz crystal

After this discussion, I'm feeling the need to fire it up and see whether
it still runs, and what the aging has done to the frequency

Philip

On 03/02/2016 07:11, Bob Camp wrote:

Hi

There is actually a range of crystals shown in the pictures. The gold
plated 5 MHz
crystal is probably an overtone part. It could be fairly precise. The 25
MHz part is
plated with something like silver. It probably is a *much* lower
precision part. There
likely are long stories that explain just why this or that package got
used in this
or that application.

Bob


On Feb 2, 2016, at 10:04 PM, Jeremy Nichols  wrote:

The OP's picture looks very much like the crystals that HP's "Frequency
and Time" division in Santa Clara (02 was their division number) used to
manufacture back in the 1970s. My picture shows a 1 MHz crystal that HP
used in the predecessor to the HP-105A (perhaps the 101A).

Jeremy

http://s323.photobucket.com/user/Jeremy5848/media/Miscellaneous/Crystal_1140587_zps0jxjpoal.jpg.html



On 2/2/2016 12:24 PM, Don Latham wrote:

You have it right, iovane. At the least, they should be protected from
light,
thermal radiation, and emf.   Won'drous things will happen if the
crystal and
its structure are subjected to radiation through the glass. I'd suggest
a foam
wrap in a tin can as a minimum. Put the oscillator cat in there too.
Don

iovane--- via time-nuts

I think that these crystals were designed to be placed in an oven,
which
worked
as a shield too. I have a similar crystal made by Racal in the 60's,
and in my
case it is fitted with the classic octal tube-type plug. It was housed
(still
is) in a heavy massive shimmering chrome-plated cylindrical brass
enclosure, a
beauty to see, It was the timebase of a tube-type synthesizer with
lots of
tubes. Themperature control was achieved by means of a mercury
thermometer in
which mercury actuated a contact when reaching a wire crossing the
capillary
tube.

Antonio I8IOV


Da: Bob Camp 
Data: 02/02/2016 13.15
A: "Discussion of precise time and frequency
measurement"
Ogg: Re: [time-nuts] Glass Envelope Quartz Crystals

Hi

Since the 25 MHz crystal has already been soldered into a circuit,
putting it

in a

socket is probably not a real good idea. It’s also a leaded part.
Even with

fat pins

sockets can be an issue. With wire leads, you are asking for trouble.

Functionally, there is little there is little difference between a
glass

package crystal

and a metal package. About the only real one is the obvious - one has
a metal

shield

you can (but sometimes don’t)  ground.

Bob



On Feb 1, 2016, at 9:58 PM, Daniel Watson 
wrote:

Hi,

I purchased a pair of interesting glass envelope crystals for a
project.
Here are some pictures:

http://syncchannel.blogspot.com/2016/02/glass-envelope-quartz-crystals.html

Does anyone have an idea about what mount/socket I should buy for
these? I
read a previous thread on the list about Bliley crystals using a B7G
mount,
but I'm not sure if that type might work here.

Also, when building up a circuit to make these oscillate, are there
any
specific differences about crystals in this package that I should
keep in
mind?


Thanks much,

Dan W.




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Re: [time-nuts] Generating a solid PPS from 10Mhz source

[Alan Melia]

Indeed Bob in the 70s I built a failure diagnostic equipment to record the 
Idd of a chip as a function of a position of a spot of light scanning the 
surface. The intensity was very low and not optimum wavelength...it was 
a scope raster demagnified by using a microscope camera accessory backwards. 
The intensity was modulated and the signal detected on a PSD and displayed 
on a modified Robot SSTV receiver.but it showed just how senstive chips 
are to light.


Alan
G3NYK

- Original Message - 
From: "Bob Camp" 
To: "Discussion of precise time and frequency measurement" 


Sent: Monday, January 18, 2016 3:11 PM
Subject: Re: [time-nuts] Generating a solid PPS from 10Mhz source



Hi

Back in the 70’s I was involved in making LCD watches. The whole “photo”
issue had not been fully through through. One day our chief marketing guy 
for
the project was driving around in Phoenix AZ. He looks down and notices 
that
his watch is dead. Pops out a spare, puts it on, confirms it it working. 
Hangs his arm out

the window and …. that one is dead as well.

We changed the die coat on the ASIC to an opaque version soon after that …

Light does indeed interact with semiconductors. It happens even on 
circuits that

you would not *think* are photo sensitive. Physics is nasty that way ….

Bob

On Jan 18, 2016, at 6:45 AM, Poul-Henning Kamp  
wrote:



In message <569bc23a.3030...@arcor.de>, Gerhard Hoffmann writes:


LEDs abused as References:


This is one of the most stupid ideas ever, because LEDs works both ways.

(Back when LED wrist-watches first came out, people soon discovered
that they would reset themselves when photographed with flash.)

If you insist on using LEDs as voltage references, the first thing
you need to do is to dip the LED in something which shields it 100%
from incoming light *including infrared*

--
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] Tait reference

[Alan Melia]

Its difficult to say unless you can contact an ex Tait dealer who maintained 
a Local authority or Utility scheme. A similar unit by Pye/Philips I have 
knowledge of, was the HS400. This contained a Toyocom 5MHz OCXO which was 
used to lock a crystal producing the required excitation for the (analogue) 
transmitter. There were two reasons for the offset, one was to avoid static 
nulls were two overlapping areas had out of phase signals, and the offset 
needed to be more than 20Hz (avoids flutter effects from the beats)and less 
than 50Hz to avoid confusing the CTCSS decoders (tone squelch).


However later Tait gear in the 800 series was synthersized, I believe, so 
this may be an stable reference source (OCXO or Rb) which could be daisy 
chained to all the channel transmitters in the site. Rubidium is not 
strictly necessary but was being installed in the 90s in some Police 
systems. In fact the Rapco GPSDOs available on eBay some couple of years ago 
came out, I believe, of London's Met Police system when they went digital.


Alan
G3NYK

- Original Message - 
From: "Adrian Godwin" 
To: "Discussion of precise time and frequency measurement" 


Sent: Monday, January 11, 2016 1:11 PM
Subject: Re: [time-nuts] Tait reference



Yes, i found that description and it put me off buying one. But there are
also references on the web (including time-nuts archive) to surplus T801s
with rubidium sources.

Anyway, I took a punt and bought one.
So I'll find out soon :).


On Mon, Jan 11, 2016 at 11:18 AM, Charles Steinmetz 


wrote:


Adrian wrote:

Are these the references with a rubidium oscillator ? They seem to have

similar models with OCXOs etc.



Tait is a manufacturer of mobile communications gear in New Zealand.  The
T801 was part of a discontinued "quasi-synchronous communications system"
-- a form of simulcasting on the same frequency by transmitters at
different locations, to fill in dead spots.  Tait's application was 
utility
and public service mobile radios (not radio broadcasting, where this 
scheme

has also been used).  Here is Tait's basic description:

The Tait Quasi-Synchronous Communication System works by broadcasting

simultaneously from several transmitters on the same frequency. The
transmitters then operate as a single transmitter giving superior 
coverage.


A Tait T801 Frequency Referenct Module acurately maintains the frequency
of the transmitters at each site.

Where required, the T801 allows small frequency offsets to prevent the
occurrence of static nulls in the overlap area.

The T801 module may be driven from one of a number of frequency
references, such as:
-- Rubidium frequency standard
-- Broadcast frequency standard
-- Oven Controlled Crystal Oscillators (OCXOs)
-- GPS Caesium Clock



This suggests that the T801 does not have an internal frequency 
reference,
but rather requires a precision external reference to function.  (It has 
a
jack labeled "INTERNAL STD OUTPUT," but that may simply be a reference 
that

is derived from the external standard, or a backup crystal oscillator to
keep the transmitter more or less on frequency if the external reference
signal is lost.)

Best regards,

Charles



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Re: [time-nuts] Loran Europe Lessay seems to be back on air?

[Alan Melia]

Yeah well its all done by computers now you dont need qualified navigators, 
the Captain can easily run it aground on his own :-)) It took a little 
longer than dumping ROs but not much.


Alan
G3NYK

- Original Message - 
From: "Brian Inglis" <brian.ing...@systematicsw.ab.ca>

To: <time-nuts@febo.com>
Sent: Wednesday, January 06, 2016 9:44 PM
Subject: Re: [time-nuts] Loran Europe Lessay seems to be back on air?



On 2016-01-04 14:11, Alan Melia wrote:
I remember being told by a senior member of the RIN that he thought it 
was a "dead duck" and a waste of money.


It appears someone also thought RIN was a "dead duck" and a waste of money 
as it too shut down at the end of 2015!


--
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada
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Re: [time-nuts] Loran Europe Lessay seems to be back on air?

[Alan Melia]

If I remember correctly the GLA(Trinity Ho.) has a contact with Babcock who 
run Anthorn which goes through to 2019 or 2020. The notice to mariners did 
not mention Anthorn but it did request that nav. receivers be turned off. If 
TH terminate that contact they will presumably have to pay Babcock anyway so 
they may as well continue "playing". From the papers it would seem the North 
Sea study has been completed.


I am just surprised that, naively, they did not get assurance from the 
French that they would keep Lessay running, because the move to eLoran was 
very much promoted by the French though they did not get a lot of support 
from other European countries.


I remember being told by a senior member of the RIN that he thought it was a 
"dead duck" and a waste of money.


Alan
G3NYK
- Original Message - 
From: "GandalfG8--- via time-nuts" 

To: 
Sent: Monday, January 04, 2016 7:26 PM
Subject: Re: [time-nuts] Loran Europe Lessay seems to be back on air?



>As of 1725, 4th January, Lessay seems to have been transmitting   again
for

at least 30 minutes, and showing the same or a slightly  stronger  signal
here on the west coast of Scotland than  Anthorn.


Are you sure it's not UK trying to rig something up for their eLoran 
trials

?

=

I'm pretty sure now that's exactly what it was, and keeping my fingers
crossed it'll be permanent once they finish playing:-)

Regards

Nigel
GM8PZR
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Re: [time-nuts] KD2BD WWVB receiver/decoder in QEX

[Alan Melia]

Thanks Bill I had not looked at the date of the latest bulletin just that it 
was still available. I suspect the major use now is the timecode.

Alan
G3NYK

- Original Message - 
From: "Bill Byrom" <t...@radio.sent.com>

To: <time-nuts@febo.com>
Sent: Monday, November 23, 2015 12:12 AM
Subject: Re: [time-nuts] KD2BD WWVB receiver/decoder in QEX



The last NPL MSF Bulletin showing their errors was over 4 years ago:
http://resource.npl.co.uk/time/bulletins/bulletin_archive.html
http://www.npl.co.uk/science-technology/time-frequency/products-and-services/time/msf-radio-time-signal

The error at a receiver over an interval of a couple of days is nearly
completely due to propagation effects. The variations in propagation
delay far exceed the error in transmitter frequency/phase control unless
there are large changes in the local weather at the transmitter site.

The phase of LF signals at 60 kHz is affected by the effective height of
the ionosphere, which forms a 60 kHz waveguide with the Earth's surface.
Unless you are very close to the transmitter, the amplitude and phase of
the received signal change significantly through each 24 hour period.
WWVB clocks should always measure the signal during the dark path (when
the propagation path between Ft Collins CO and your location is fully
dark), since that is when the signal is strongest and tends to have a
more stable phase.

WWVB clocks can get UTC with an uncertainty of about 100 microseconds,
according to NIST: http://www.nist.gov/pml/div688/grp40/wwvb.cfm

--
Bill Byrom N5BB



On Sun, Nov 22, 2015, at 04:16 PM, Alan Melia wrote:

Hi Bob I have just realised that MSF may work diffently?? The Anthorn
signal is monitored by NPL at Teddington, West of London and frequency
off-sets twice a day are published in parts in 10^12 on their
web-site.involving lot of averaging I think. They do not recommend
using the signal after dark.

You certainly could predict roughly the the skywave phase change during
the
day and the variation as the sun angle changes on the path over the year.
It
gets more difficult if there are flares or geomagnetic storms. If two
independent stations at slightly different distances collect information
it
could be corrected even more accurately.

The same ionospheric problem occurs of course with Loran, and the now
closed
Decca system..

Alan
G3NYK



- Original Message -
From: "Bob Camp" <kb...@n1k.org>
To: "Nick Sayer" <nsa...@kfu.com>; "Discussion of precise time and
frequency
measurement" <time-nuts@febo.com>
Sent: Sunday, November 22, 2015 7:34 PM
Subject: Re: [time-nuts] KD2BD WWVB receiver/decoder in QEX



Hi

The most basic gotcha with WWVB is that propagation can (and does) shift
the
carrier more than a full cycle over the course of a day. That’s at 60 
KHz,

so one
cycle is a lot (as in 16.666 ppm). Even at one second with a not so 
great

receiver
and a poor antenna, GPS should give you ~0.01 ppm. Right up front, you
have a bit of a problem.
(Yes I’m mixing measurements in that comparison, but the point is still
valid).

What I keep wondering is - There is no big mystery about the WWVB
transmitter's
location. You likely know your own location as well. Part of 
demodulating

the data
gives you day of the year. From that you can figure out some of the 
basics

of the
propagation effects (sunrise is at X:XX sunset is at … etc). You also
could grab stuff
like weather data fairly easily (no idea if that actually helps). If you
fit out the basic
propagation impacts, WWVB could get a lot better. At the very least, you
would know
when to ignore the signal.

So yes, you could do better today than they could back in the good old
days in terms of
the propagation coarse effects.

Unfortunately, there also is data on 24 hour comparisons of WWVB carrier
(same time of
day, one day apart). If you pick your time right (noon or midnight), the
variable propagation
can be reduced quite a bit. Based on that data, you are doing well at 
100

ppt over
24 hours. Might the new modulation help that by 10X? ..maybe. GPS over a
24 hour
period should be giving you something in the 0.1 to 0.01 ppt range (same
sort of pick a likely
stable ionosphere time slot and compare).

Does that make a WWVB device un-interesting? Not by any means. If you
stretch out the
time, both systems get down into the “I have nothing else that good”
range. Checking one
against the other is indeed an interesting thing to do. You just need a
**lot** of time to do it.

Bob



On Nov 22, 2015, at 12:41 PM, Nick Sayer via time-nuts
<time-nuts@febo.com> wrote:



On Nov 22, 2015, at 7:47 AM, paul swed <paulsw...@gmail.com> wrote:

As mentioned a nice answer to the wwvb modulation change.
I looked up the parts and it seems that they have gone into the NOS
state.
Though you can get some from digikey and such especially in the SOIC
package. Also the VCO isn't available.
It appears that the Chines

Re: [time-nuts] KD2BD WWVB receiver/decoder in QEX

[Alan Melia]

Hi Bob I have just realised that MSF may work diffently??  The Anthorn 
signal is monitored by NPL at Teddington, West of London and frequency 
off-sets twice a day are published in parts in 10^12 on their 
web-site.involving  lot of averaging I think.  They do not recommend 
using the signal after dark.


You certainly could predict roughly the the skywave phase change during the 
day and the variation as the sun angle changes on the path over the year. It 
gets more difficult if there are flares or geomagnetic storms. If two 
independent stations at slightly different distances collect information it 
could be corrected even more accurately.


The same ionospheric problem occurs of course with Loran, and the now closed 
Decca system..


Alan
G3NYK



- Original Message - 
From: "Bob Camp" 
To: "Nick Sayer" ; "Discussion of precise time and frequency 
measurement" 

Sent: Sunday, November 22, 2015 7:34 PM
Subject: Re: [time-nuts] KD2BD WWVB receiver/decoder in QEX



Hi

The most basic gotcha with WWVB is that propagation can (and does) shift 
the
carrier more than a full cycle over the course of a day. That’s at 60 KHz, 
so one
cycle is a lot (as in 16.666 ppm). Even at one second with a not so great 
receiver
and a poor antenna, GPS should give you ~0.01 ppm. Right up front, you 
have a bit of a problem.
(Yes I’m mixing measurements in that comparison, but the point is still 
valid).


What I keep wondering is - There is no big mystery about the WWVB 
transmitter's
location. You likely know your own location as well. Part of demodulating 
the data
gives you day of the year. From that you can figure out some of the basics 
of the
propagation effects (sunrise is at X:XX sunset is at … etc). You also 
could grab stuff
like weather data fairly easily (no idea if that actually helps). If you 
fit out the basic
propagation impacts, WWVB could get a lot better. At the very least, you 
would know

when to ignore the signal.

So yes, you could do better today than they could back in the good old 
days in terms of

the propagation coarse effects.

Unfortunately, there also is data on 24 hour comparisons of WWVB carrier 
(same time of
day, one day apart). If you pick your time right (noon or midnight), the 
variable propagation
can be reduced quite a bit. Based on that data, you are doing well at 100 
ppt over
24 hours. Might the new modulation help that by 10X? ..maybe.  GPS over a 
24 hour
period should be giving you something in the 0.1 to 0.01 ppt range (same 
sort of pick a likely

stable ionosphere time slot and compare).

Does that make a WWVB device un-interesting? Not by any means. If you 
stretch out the
time, both systems get down into the “I have nothing else that good” 
range. Checking one
against the other is indeed an interesting thing to do. You just need a 
*lot* of time to do it.


Bob


On Nov 22, 2015, at 12:41 PM, Nick Sayer via time-nuts 
 wrote:




On Nov 22, 2015, at 7:47 AM, paul swed  wrote:

As mentioned a nice answer to the wwvb modulation change.
I looked up the parts and it seems that they have gone into the NOS 
state.

Though you can get some from digikey and such especially in the SOIC
package. Also the VCO isn't available.
It appears that the Chinese sight has the lmc6484 and LM387n at 
reasonable

prices for small quantities. Most likely will order from there.
Have not checked out the PIC chip yet.
The 74HCXX are common and reasonable.


That’s kind of a shame. I’m sure a redesign with modern SMD parts could 
be accomplished.


The big question is how the stability of a wwvb disciplined oscillator 
would compare to a GPS disciplined one (all other things being equal). 
Well, it’s a big question for me, since I have no idea, but I imagine 
simply asking here will give an immediate answer. :)


I’d have to guess that the PLL would behave better given a 60 kHz 
reference rather than a 1 Hz one. But how stable is that 60 kHz reference 
after going through, what, a thousand miles of ionosphere or so?

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Re: [time-nuts] How did they distribute time in the old days?

[Alan Melia]

Well I dont know if it was used for that but the16kHz VLF station at Rugby 
call-sign GBR was rebuilt in 1967 and the output tank circuit stiffened to 
provide better phase stability specifically foe international time standard 
comparison. The transmitter was used for initial comparisons between NPL and 
NBS (later NIST) time standards. It was also the starting point for the 
Omega nav system. Prior to that accurate time data was passed over twisted 
pairs in UK and probably Europe.


Alan
G3NYK
- Original Message - 
From: "Hal Murray" 
To: "Discussion of precise time and frequency measurement" 


Cc: 
Sent: Wednesday, October 14, 2015 6:12 AM
Subject: [time-nuts] How did they distribute time in the old days?




hol...@hotmail.com said:

Somewhat time-nut related...  the project main application needed
millisecond consistent (not necessarily accurate) time stamps on a
world-wide network.  That was in the pre-gps, pre-fiber, pre-historic
before-times.  I don't think that they ever quite got there.


World wide seismology took off in the early 1970s as background for 
nuclear

underground non-testing treaties.  Both the US and the USSR had to be sure
they could detect the opponents tests and distinguish tests from 
earthquakes.

We had seismic stations scattered around the globe.

Does anybody know how they distributed time back then and/or how 
accurately

they could do it?

Google says the speed of sound in rock is 6-8 km/s so 10 ms error would be
100 meters.  That seems like a reasonable ballpark.



--
These are my opinions.  I hate spam.



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Re: [time-nuts] Would this work as a frequency standard? Would it damage the Stanford Research function generator?

[Alan Melia]

Hi David I live a little to the North of you and I have used R4 a number of 
years ago...In fact I spotted and reported to NPL  breathing or hunting on 
the output compared to my two Austron 1250As the period was about 100secs. I 
was emailled a couple of months later to say the exciter had failed.not 
the Rb but something in the chain and the contractor didn't even have an 
off-air standard receiver. It did not affect the long term average in parts 
to 10^12 but it made the short term accuracy very poor ..up to 1.5 in 
10^8 over 10secs


I gave up monitoring it when I got regular wideband interference which 
temporaly unlocked my off-air standard so check you can get a clean 
continuous signal. Daytime performance is not too bad but after-dark is not 
so good.


Some earlier EGG Lock-in amps have a PLL function, outputting a DC signal 
that is the phase difference.


Alan
G3NYK

- Original Message - 
From: Dr. David Kirkby (Kirkby Microwave Ltd) 
drkir...@kirkbymicrowave.co.uk
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Sunday, July 19, 2015 3:49 PM
Subject: [time-nuts] Would this work as a frequency standard? Would it 
damage the Stanford Research function generator?




I had a plan to construct an off-air frequency 10 MHz standard based on
the 198 kHz from the Droitwich radio 4 transmitter, just by hooking up
various bits of test kit and writing a computer program to control the
equipment via GPIB. No electronics, apart from an antenna, would need to 
be

built at all.  My thoughts were the following - hopefully it makes sense,
if not I could add a drawing.

1) Connect an antenna suitable for 198 kHz into the input terminal of an
EGG 7260 dual-phase lock-in amplifier.

http://www.signalrecovery.com/download/190163-A-MNL-D.pdf

This is not a very nice lock-in to use interactively, but is okay via 
GPIB.


2) Set the EGG lock-in amplifier to use an external reference.

3) Feed the reference input of the lock-in amplifier from a Stanford
Research DS345 30 MHz function generator

http://www.thinksrs.com/products/DS345.htm

which is set to output a 198 kHz square (or sine?) wave. The function
generator has a frequency resolution of 1 uHz, and 12 bits of resolution 
on

the DAC. This can produce arbitrary waveforms.

This function generator has a 40 MHz crystal, the frequency of which can 
be
set by adjusting the Calbytes via GPIB - similar to the SR620 
time-interval

counter. Obviously if the frequency of the 40 MHz oscillator is high, so
the output frequency will be above 198 kHz. The specification of the
oscillator are

Frequency: 40 MHz (according to the manual, unless a typo)
Type: Ovenized AT-cut oscillator
Stability:  0.01ppm, 20 - 60°C
Aging:  0.001ppm/day
Short Term:  5 x 10-11 1s Allan Variance

4) Use the lock-in as a phase detector, measuring the difference in phase
between the function generator and the 198 kHz from Droitwich. The
sensitivity of the lock-in, as well as the time-constant of the filters,
can be adjusted via GPIB.

5) Write a computer program that tries to set the oscillator in the
function generator to exactly 40 MHz via GPIB, based on the rate of change
of phase between Droitwich and the function generator.

6) Since the function generator has a 10 MHz reference output, which is
derived from the 40 MHz crystal, It should give me a solderless 10 MHz
frequency standard.

Does this seem viable, or have I overlooked something? I'm not looking to
build a lab standard - just have a bit of fun.

Does anyone know if regularly writing to the calbytes of the function
generator would damage it?

Dave
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Re: [time-nuts] Loran C returning to a station near you...

[Alan Melia]

It just depends what you mean by that :-) I could lock to Lessay and Anthorn 
at frequencies in the 136kHz amateur band, using some S/N DSP software 
writen by Peter Matinez G3PLX.


Alan
G3NYK
- Original Message - 
From: Poul-Henning Kamp p...@phk.freebsd.dk
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com; Bob Camp kb...@n1k.org

Sent: Wednesday, July 15, 2015 7:41 AM
Subject: Re: [time-nuts] Loran C returning to a station near you...




In message 3e8a4741-f565-4d2f-834f-62eca1ca1...@n1k.org, Bob Camp 
writes:



If you look at the spectral width of the existing Loran-C (or
similar) waveform, it’s a massive thing. You would have a hard time
coming up with something that spreads more crud around the VLF range.


The reason Loran-C spreads crud is *only* the combinationa of the
pulse-groups and the periodicity of the GRI.

The pulses themselves are entirely contained inside the allocated
frequency band.


--
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] LORAN-C reception in the UK

[Alan Melia]

Dave check with the Triniity House web site they are the sponsors of the 
Anthorn slave site, the master station is at Lessay on the St. Malo 
penninsular so should be strong. There is (or was) a full descrition of the 
option to GPSon the website.  I believe there should be at least 5 years 
to run on the original 10 year contract. The transmission is eLoran, at bit 
like Loran-C with a DGPS. I think there is an extra pulse in the train, I 
dont think this will affect the receiver you quote. The 100kHz signal should 
be OK in daytime may will suffer some phase shifts at night at more extreme 
range. This should not be a problem at your range from Lessay.


Alan
G3NYK

- Original Message - 
From: Dr. David Kirkby (Kirkby Microwave Ltd) 
drkir...@kirkbymicrowave.co.uk
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Friday, July 10, 2015 1:14 PM
Subject: [time-nuts] LORAN-C reception in the UK



How good/bad would a LORAN-C frequency reference such as the Stanford
Research FS700 work in the UK?  I live about 60 km to the east of central
London.

Is there any future for LORAN-C in the UK?

I am looking for a frequency reference that is not GPS - I already have a
GPS frequency reference but would like to compare it with something
independent of GPS.  Just having two GPS receivers provides two signals
which are probably highly correlated.

Dave.
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Re: [time-nuts] Austron 1250A

[Alan Melia]

Hi Ole Mmmm well I have 2 and a friend has one all had dead batteries, 
quickly removed, but we didnt have a manual then so we just ran them without 
them batts. Our power is quite reliable. My pair have been running 
continuously for around 7 years now with no signs of problem and no relay 
chatter. The crystals are well aged now :-))


Alan
G3NYK

- Original Message - 
From: Ole Petter Ronningen olep...@gmail.com

To: time-nuts@febo.com
Sent: Wednesday, February 18, 2015 5:46 PM
Subject: [time-nuts] Austron 1250A



Hello

On a whim I purchased an Austron 1250A off of eBay, tested for power on
only. I somehow doubt they told the whole truth there, as the unit makes 
a

*very* noticable buzzing sound when powered on!

The sound comes from a relay on the regulator board, oscillating wildly. I
have a hunch that this might be because the NiCad batteries are stone 
dead.

Has anyone experienced this relay going nuts?`

Also, the manual gives clear warning not to operate the unit with the
battery pack removed, but gives no reason.. Does anyone know why this 
might

be a bad thing?

Thank you!
OleP
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Re: [time-nuts] 510 doubler and old Toko RF catalogue (Cirkit 2nd ed.1994)

[Alan Melia]

Hi Andrea I have here a Cirkit  2nd edition Toko catalogue dated 1993 (a 
firm local to me I dealt with quite a lot) The cat is in good condition but 
it is 128 pages and a glued spine so scanning risks breaking it up. However 
the 10k range occupies just one page and if the part adjacent to the spine 
does not copy well all you will lose is the 100off price column (and I dont 
think you can buy them for that now 20 years on :-))  )  Give me a little 
time and I will do you a scan of the page, and mail it direct as a PDF.


I might actually have some new Toko coils in the component drawers but they 
may not be 10K. However I also have a lot of 5MHz OCXOs including Racal an 
Toyocom so I might have something useful if you dont find a source nearer to 
you.


Best Wishes
Alan
G3NYK

- Original Message - 
From: Andrea Baldoni erm1ea...@ermione.com

To: time-nuts@febo.com
Sent: Tuesday, January 27, 2015 3:53 PM
Subject: [time-nuts] 510 doubler and old Toko RF catalogue (Cirkit 2nd 
ed.1994)




Hello All.

Now I have some 5MHz DOCXO. I have started to experiment with them
and I would like to build a frequency doubler.
I already saw the very nice circuit from Gerhard Hoffmann for the Lucent, 
I saw

some diode circuits from Wenzel (my oscillators output around 1.5Vpp
loaded, too scarce for diodes alone; I used a 1:2 transformer just to try
and I obtained the 10MHz but not good for anything) and I saw the doubler
circuit Racal Dana used in some counters I attached.

I would like to build something like one of those; it's a full wave 
rectifier
made by a differential amplifier and two diodes, followed by a 10MHz 
amp/filter

chain much like the IF of FM radios (with AGC too!). I don't know if it's
adequate for serious use; I also saw the Z3811-80007 doubler board used in
Z3815A and Z3805A according to the seller, much more modern and surely 
better,

but I have not its schematic. Someone knows it?

I have bought one of the Racal units, just to have the opportunity to 
fiddle
with an already working one; I identified the IF transformers used there 
and
are Toko common 10.7MHz Q=80 unit. They are not built anymore but it's 
possible

to find similar ones in Internet; however it happens to me frequently
to need information about the old Toko 10K series and there is not any
comprehensive source. I saw I share this frustration with many people in 
the

electronics newsgroups.
Finally I found that a (fairly) complete Toko catalog existed, it was sold 
by

Cirkit in '94 and it's not available anymore.
Someone has it in PDF form, or want to borrow it to me to scan it?

By the way, I see that really many of the 10MHz reference out there, are 
in

effect doubled 5MHz ones so build a doubler seems reasonable for me.

Best regards,
Andrea Baldoni
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Re: [time-nuts] Mechanical 1PPS Oscillator Disciplining

[Alan Melia]

Hi David yes I think I have seen similar but not as low as that. If you 
compare the suspension points the different vibrational mode should 
obvious.the suspension point is at a node. I think some of these are 
quite difficult to excite, I have not seen any suggested circuits but I have 
not looked too hard.


Alan
- Original Message - 
From: David J Taylor david-tay...@blueyonder.co.uk
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Saturday, January 10, 2015 7:06 AM
Subject: Re: [time-nuts] Mechanical 1PPS Oscillator Disciplining


Hi Tom dividing down wasn't always necessary I have sample from the UK 
GPO

Crystal Factory of NT-cut bars, quartz tuning fork, and Gapped Ring
crystals, the latter marked 400cps (pre Hertz :-))  )  I think these are
post WWII because they are mounted in IO base GT style tube envelopes.
Dividers were achieved with neons and locked multivibrators, where
necessary, I believe.
[]
Alan
G3NYK


I have one 500 c/s GEC crystal in an octal base which is thinner than a 
60 Kc/s one, so a different mode.  Never had it working, though.


73,
David GM8ARV
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
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Re: [time-nuts] Mechanical 1PPS Oscillator Disciplining

[Alan Melia]

Hi Tom dividing down wasn't always necessary I have sample from the UK  GPO 
Crystal Factory of NT-cut bars, quartz tuning fork, and Gapped Ring 
crystals, the latter marked 400cps (pre Hertz :-))  )  I think these are 
post WWII because they are mounted in IO base GT style tube envelopes. 
Dividers were achieved with neons and locked multivibrators, where 
necessary, I believe.


The original ( 1926 ) frequency source for Rugby GBR  16kHz radio station 
was an invar tuning fork with a tube maintaining amplifier. I cannot find 
any information on syntonising that but it probably was not necessary.

Alan
G3NYK


- Original Message - 
From: Tom Van Baak t...@leapsecond.com
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Friday, January 09, 2015 9:51 PM
Subject: Re: [time-nuts] Mechanical 1PPS Oscillator Disciplining



Andy,

Yes, Neal Stephenson's Mother Earth Mother Board article is a classic that 
every time nut should read at some point.
The one page version is at 
http://archive.wired.com/wired/archive/4.12/ffglass_pr.html


Prior to quartz, pendulum clocks and tuning fork oscillators were the 
standard. Even until the 1950's or early 1960's tuning fork oscillators 
were used when one needed accurate frequency in the audio range. That's 
because dividing down high frequency quartz oscillators to, say, 60 Hz or 
400 Hz required lots of circuitry. Not sure if Neal's reference to 
vibrating reed is what we would call a tuning fork, or if it's something 
else.


Here in the US General Radio made precision tuning fork oscillators. Model 
numbers 213, 723, 813, 815. One example is at 
http://leapsecond.com/museum/gr815b/
Also check out old issues of General Radio Experimenter magazine for 
details on these wonderful instruments.


Pendulum clocks were also used in power plants around the world to keep 
the grid synchronized. There is occasional discussion about this on clock 
collecting or horology forums. They are precious and can be extremely 
accurate, as good as a second a year.


Since pendulum clocks were better long-term timekeepers and generated only 
0.5 or 1 Hz signals, a PDTF (Pendulum Disciplined Tuning Fork) made sense. 
Has a nice ring to it, doesn't it.


/tvb

- Original Message - 
From: Andy Bardagjy a...@bardagjy.com
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Friday, January 09, 2015 9:22 AM
Subject: [time-nuts] Mechanical 1PPS Oscillator Disciplining


From a fascinating (albeit long) article about transatlantic communication 
cables


http://archive.wired.com/wired/archive/4.12/ffglass.html

On the bottom of page 45 to the top of page 46

Each piece of equipment on this tabletop is built around a motor that 
turns over at the same precise frequency. None of it would work - no 
device could communicate with any other device - unless all of those 
motors were spinning in lockstep with one another. The transmitter, 
regenerator/retransmitter, and printer all had to be in sync even though 
they were thousands of miles apart.


This feat is achieved by means of a collection of extremely precise analog 
machinery. The heart of the system is another polished box that contains a 
vibrating reed, electromagnetically driven, thrumming along at 30 cycles 
per second, generating the clock pulses that keep all the other machines 
turning over at the right pace. The reed is as precise as such a thing can 
be, but over time it is bound to drift and get out of sync with the other 
vibrating reeds in the other stations.


In order to control this tendency, a pair of identical pendulum clocks 
hang next to each other on the wall above. These clocks feed steady, 
one-second timing pulses into the box housing the reed. The reed, in turn, 
is driving a motor that is geared so that it should turn over at one 
revolution per second, generating a pulse with each revolution. If the 
frequency of the reed's vibration begins to drift, the motor's speed will 
drift along with it, and the pulse will come a bit too early or a bit too 
late. But these pulses are being compared with the steady one-second 
pulses generated by the double pendulum clock, and any difference between 
them is detected by a feedback system that can slightly speed up or slow 
down the vibration of the reed in order to correct the error. The result 
is a clock so steady that once one of them is set up in, say, London, and 
another is set up in, say, Cape Town, the machinery in those two cities 
will remain synched with each other indefinitely.


Does anyone know any other history about that particular piece of 
equipment?


Cheers!

Andy ◉ Bardagjy.com ◉ +1-404-964-1641

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Re: [time-nuts] Frequency distribution isolation transformers YCL20F001n arrived

[Alan Melia]

Hi Paul I confirm the 17MHz LPF response I didn't measure them for flatness 
:-)) The source I used was surplus 16way 10BaseT switches which were junked 
some time back but may still be lying in the back of store-room 
cupboards.you get a lot on one board that way.


Alan
G3NYK

- Original Message - 
From: paul swed paulsw...@gmail.com

To: Time-nuts time-nuts@febo.com
Sent: Sunday, December 14, 2014 4:18 PM
Subject: [time-nuts] Frequency distribution isolation transformers 
YCL20F001n arrived



Another Time-nut suggested the use of 10 baseT ethernet transformers for 
10

MHz isolation that he pulls from old ethernet boards. The 20F001n. These
are available from UTSource on ebay at 90 cents each NOS. Ordered 20.

Well I have to say as a BPF or something for 10 Mhz they are lousy. BUT
then how could they be when they are a pretty flat transformer from 40 KHz
to 17 MHz! Take that Mini-Circuits. (Only in jest) Yes there are some 
lumps

and bumps in that pass band But not large maybe 1-1.3db I need to get much
more accurate. But now I have a nice transformer that can work at WWVB 60
Khz as well as with frequency distribution.
They come in a dip foot print and 2 X to a package.
I have more to check because to good to be true almost always is. At least
for me.
Regards
Paul
WB8TSL
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Re: [time-nuts] 1968 Scientific American Magazine: Cesium ClockStandards

[Alan Melia]

Hi Dave, as a long time reader (since 1955) and subscriber I remember the 
Amateur scientist pages ending in the 1980s. I think the contributer 
retired. At around that time I think the many adherents formed the Society 
of Amateur Scientists. Though I have not visited fot several years the web 
site was www.sas.org  and I believe had pdfs of old SciAm Amateur Scientist 
articles.


I particularly remember one scary article about an X-ray generator that 
consisted of a 6J5G tube ( I think a triode valve in the UK  :-))  ) with a 
piece of aluminium foil secured round the smaller diameter part of the top 
with a twist of copper wire, and conected between the cathode pin and the 
foil, a 2kV psu !! The end of the tube cathode (and heater wire) was clearly 
visible through the top and formed a spot source of electrons. I believe an 
X-ray plate of a hand was included in the article !!


There were many inovative ways of building quite sophisticated experiments. 
Another I rememver was a Proton precession magnetometer using a radar 
magnetron magnet.


Alan
G3NYK



- Original Message - 
From: paul swed paulsw...@gmail.com
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Wednesday, December 10, 2014 1:20 PM
Subject: Re: [time-nuts] 1968 Scientific American Magazine: Cesium 
ClockStandards




Dave I do not know why but it was one of two things as I barely recall.
Magazine format change (Need dumber for more readers) or the fellow died.
That was a long time ago.
I know as a kid that inspired me on more then one occasion to do 
something.

They are still a good read. there was some pdfs at some sight or a book or
something.
Regards
Paul
WB8TSL

On Wed, Dec 10, 2014 at 6:16 AM, Dr. David Kirkby (Kirkby Microwave Ltd) 
drkir...@kirkbymicrowave.co.uk wrote:


I see this on eBay - it might interest some, and at $10 it will not
break the bank


http://www.ebay.ca/itm/1968-Scientific-American-Magazine-Cesium-Clock-Standards-Measurement-DNA-Dis-/381078816062

BTW, does anyone know why the Amateur Scientist column was dropped in
Scientific American? Perhaps the thought they might get sued if a
suggestion was made to use anything more dangerous than a teaspoon of
salt!

Dave
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Re: [time-nuts] 10811

[Alan Melia]

Yes below about 4v is the only place where you get the real Zener effect, 
as you go above 5v it becomes Avalanche Breakdown. The trick is zener effect 
has a negative tempco and avalanche a positive one (I thinkthey are 
opposite senses anyway :-))  ) the result is a regulator diode 
(zenerso called) specced at around 5 to 5.5 volts has a near zero 
overall tempco.


Alan
G3NYK



- Original Message - 
From: Brooke Clarke bro...@pacific.net
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Tuesday, November 18, 2014 10:31 PM
Subject: Re: [time-nuts] 10811



Hi Rick:

When working on Tunnel Diode amplifiers we used (AFAICR) 5.1 V Zener 
diodes to stabilize the lower voltage that drive the diode.
5.1V was supposed to have excellent temperature characteristics in terms 
of repeatability (don't remember if low noise was part of the selection 
criteria).

http://www.prc68.com/I/Aertech.shtml#TDA
The boards with the terminals have the Zener and a custom compensation 
network using both Veco (spelling?) (-TC) and Balco (+TC) and fixed 
resistors so that the gain stays constant over mil temperature ranges.


Mail_Attachment --
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
http://www.prc68.com/I/DietNutrition.html
Richard (Rick) Karlquist wrote:



On 11/17/2014 5:54 PM, Bert Kehren via time-nuts wrote:
I ground one side of the tuning diode and use the 2 to 12 V as the 
external

  OCXO for my FRK's along with increasing the time constant. I have not
verified it but I think removing the zener Voltage should also improve 
ADEV.

Bert Kehren



The choice for the Zener diode came from my old boss at HP,
who was very knowledgeable about using discrete zener diodes
as low noise references.  According to him, this particular
part number has very respectable noise.  This is just something
you have to know experientially, there is no theory of zener
noise AFAIK.  You might try measuring the noise of the 6.2V
reference voltage directly at baseband, and then multiplying
by the 1 Hz/volt sensitivity.  Let us know your results.

Rick Karlquist N6RK
(Now retired from HP/Agilent/Keysight)


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Re: [time-nuts] Division Circuit

[Alan Melia]

Isn't the 10i/p gate to do the divide by N+1?? not just to avoid an all 
zeros switch on which does not need all 10 stages fed back if all you want 
is an N stage ring counter??

Alan
G3NYK

- Original Message - 
From: Tim Shoppa tsho...@gmail.com
To: Said Jackson saidj...@aol.com; Discussion of precise time and 
frequency measurement time-nuts@febo.com

Sent: Friday, November 14, 2014 9:53 PM
Subject: Re: [time-nuts] Division Circuit



Yes! I did find a patent that illustrated the exact same feedback circuit
as in the EE times article. But most self-decoding ring counters in
mass-produced applications use simpler lower propagation-delay gate
arrangements to ensure the counter self-corrects any defective sequences.
e.g. look at how the CD4017 does not use a 10 input NAND gate!!!

Tim N3QE

On Fri, Nov 14, 2014 at 4:39 PM, Said Jackson via time-nuts 
time-nuts@febo.com wrote:


The premise of higher than normal click speed is false in the article
too because the complex NOR gate is slow with that many inputs, and its 
tpd

needs to be added to the Tsu and Tco of the flip flop chains, as well as
the pcb propagation delays through the worst case trace..

It would have been faster to simply use a single reset RC delay to reset
all FF asynchronously while only setting one FF at the same time during
power-on. That would remove the Nor gate delay from the max speed
calculation..

Sent From iPhone

 On Nov 14, 2014, at 12:13, Don Latham d...@montana.com wrote:

 Thanks. You reminded me of the time when design ideas really had
content. No
 more, I'm afraid...
 Don

 Azelio Boriani
 No need to digitize, the article is available here:
 
http://www.edn.com/design/test-and-measurement/4347165/Circuit-divides-frequency-by-N-1

 or here (in .PDF):
 ftp://ztchs.p.lodz.pl/PRP/PRP_2006_2007/71102di.pdf

 On Fri, Nov 14, 2014 at 8:02 AM, Perry Sandeen via time-nuts
 time-nuts@febo.com wrote:
 List,



 I’ve digitized and edited an article titled* Circuit DividesFrequency
by N+1
 by Bert Erickson, Fayetteville, NY from EDN 7/11/2002*.



 Essentially, this circuit is expandable and allows for adivision by 
 any

 number plus one.



 Anyone who wants a PDF copy please send me an original emailoff list.



 Regards,



 Perrier


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

 Dr. Don Latham AJ7LL
 Six Mile Systems LLC
 17850 Six Mile Road
 Huson, MT, 59846
 mail:  POBox 404
 Frenchtown MT 59834-0404
 VOX 406-626-4304
 Skype: buffler2
 www.lightningforensics.com
 www.sixmilesystems.com


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Re: [time-nuts] Quad Driven Mixer 5 to 10 MHz Doubler Atricle

[Alan Melia]

As a subscriber to QEX I saw this article but thought that the bi-phase 
rectifier was a lot easier and has be well characterised by the 
time-nuts experts. Now it has shown up here I would be interested to hear 
from those experimenting how badly the NE602 performs compared with a 
passive DBM for nuts-style applications :-))  I have a pile of kit with 
5MHz VCXOs (Racal and Marconi) including an excellent GPSDO by Rapco.


Alan
G3NYK

- Original Message - 
From: Dave Daniel kc0...@gmail.com
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Wednesday, November 12, 2014 10:36 PM
Subject: Re: [time-nuts] Quad Driven Mixer 5 to 10 MHz Doubler Atricle


I believe I have a PDF copy of the article if anyone wants it. It's about 
1.3 MB in size.


DaveD

On 11/12/2014 2:36 PM, Don Latham wrote:

It's interesting. I took the hint, and tried sin(a)*sin(b) expand and set
b=a+pi/2. fun fun fun.
All that's needed in theory is a mixer and a pi/2 phase shifter at 5 MHz.
Probably a bunch of other stuff because of real parts :-) Minicircuits 
will

sell you one, packaged, for about 50 rasbucknicks.
Don

Dave M

I am able to download the files associated with the article, but not the
article itself.  Guess I need to be a paying member to get the article. 
The

only files in the download are the XLS file for calculating the filter
values, and the parts list.

It's at http://www.arrl.org/qexfiles in the year 2011 listings, filename
3x11_Roos.zip
titled Converting a Vintage 5 MHz Frequency Standard to 10 MHz with a 
Low

Spurious Frequency Doubler

Dave M

John C. Roos via time-nuts wrote:

Several list members contacted me expressing interest in the
article. None of them were able to download much or anything
from the ARRL QEX web site. That includes me and other ARRL members.
I am working the issue with one call to ARRL so far today. I will
contact Larry Wolfgang at ARRL and see what Ican bust loose. So
hang in there. It is a cute technique, not originated by me, but
useful. Right now I have to get the ARRL FMT done first.
-73 john c roos k6iql


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Re: [time-nuts] BBC TV program Click has material about GPS jammingand e Loran

[Alan Melia]

The politics of this system are a bit dubious as are the claims on accuracy 
and freedon from jamming. But it does give us another off-air frequency 
standard.


Alan
G3NYK

- Original Message - 
From: Dr. David Kirkby (Kirkby Microwave Ltd) 
drkir...@kirkbymicrowave.co.uk
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Saturday, November 01, 2014 3:07 PM
Subject: [time-nuts] BBC TV program Click has material about GPS 
jammingand e Loran



Click is a short TV program produced by the BBC about tech related 
things.


Anyway, the issue I see today (1/11/2014)

http://www.bbc.co.uk/programmes/b04p21jv

had a bit about GPS failure, GPS jamming, and use of eLORAN as a backup.


*Hopefully* you can see it on the BBC iPlayer if interested, although
I am not sure if those outside the UK can see it - you might need to
use a proxy server in the UK, since I have no idea if they block
access based on IP.

Also more on the BBC in the last 24 hours or so about this.

http://www.bbc.co.uk/news/science-environment-29758872


Dr. David Kirkby Ph.D CEng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Essex, CM3 
6DT, UK.

Registered in England and Wales, company number 08914892.
http://www.kirkbymicrowave.co.uk/
Tel: 07910 441670 / +44 7910 441670 (0900 to 2100 GMT only please)
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Re: [time-nuts] Digital temperature compensation

[Alan Melia]

Mmmm yes you can see the equation evaluation starting to rise in your 
Warmer plot, as Mark says, which will make a nonsense of the formula if 
your summer temps get above 28.


Why not a table and then interpolate between the table data points?. You 
might have more points where the changes are greater.
The colder plot looks cubic maybe for a crystal made for 20 deg C ?? But 
depending on the oscillator electronics you may have component tempcos 
affecting the frequency as well?
I suspect the turnover at 21deg C should be a smooth curve not as your 
formula predicts. Which suggests that you have too too high an order of 
polynomial I think, but you may not get a good fit with a cubic if other 
effects are present.


Alan
G3NYK


- Original Message - 
From: Dan Drown dan-timen...@drown.org

To: time-nuts@febo.com
Sent: Saturday, November 01, 2014 10:07 PM
Subject: Re: [time-nuts] Digital temperature compensation


I gave zunzun a try and the one with the lowest root mean squared error 
was:

f(x) = a( x**0.5) + b( x ) + c( sin(x) ) + d( cos(x) )

It got 0.202 RMSE, so I guess I'll stick with my original function as  it 
seems to be closer to what I expect will happen at colder/hotter  temps.


You have a good point about temperatures outside my data samples.   Once 
it gets hot again in the summertime, I'm sure I'll have to  re-evaluate 
this.


Quoting Mark Sims hol...@hotmail.com:
You could try submitting your data to zunzun.com   It will fit it to 
around 40,000 different curves and find the best ones.


Beware that with all curve fitting formulas,  once your live data  starts 
to wander out of the range of your original curve fit data,   things can 
go rather badly...


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Re: [time-nuts] Price of LTE Lite GPSDO vs Trimble Thunderbolt.

[Alan Melia]

Said I read through the description carefully .I suggest you request a 
refund from eBay for their use of incompetant computer translation which 
fails to recognise English technical words and phases, so blocking your paid 
for posting. The trigger can only be due to a stupid word selection in 
translation. I can see no English (or American :-))  ) word that could be 
responsible.


Alan
G3NYK


- Original Message - 
From: S. Jackson via time-nuts time-nuts@febo.com

To: sylva...@netcourrier.com; time-nuts@febo.com
Sent: Saturday, October 18, 2014 9:02 PM
Subject: Re: [time-nuts] Price of LTE Lite GPSDO vs Trimble Thunderbolt.



Hello Mr Richard,

that's a first! While I lived in Germany for almost 2 decades, I am not
sure what other connection the listing could have to Nazi propaganda??!

If anyone has any suggestions how to reword the listing I would love  to
hear them.

For now, can you use a proxy server to get access to the site? Don't we
just love internet censorship.

Bye,
Said


In a message dated 10/18/2014 12:35:27 Pacific Daylight Time:

Mr  Jackson,

May I suggest you rewrite the eBay description for the  LTE-Lite. As it
stands, it triggers the anti-nazi filters that block some  items from
being displayed in France possibly some other countries (at  least
Germany and Austria):

Unfortunately, access to this  particular item has been blocked due to
legal restrictions in some  countries. We are blocking your viewing in
an effort to prevent  restricted items from being displayed.
Regrettably, in some cases, we  may prevent users from accessing items
that are not within the scope  of said restrictions because of
limitations of existing technology.  Please accept our apologies for
any inconvenience this may cause, and  we hope you may find other items
of interest on eBay.


Best  regards,

Sylvain RICHARD


Le 18/10/2014  19:58, David J Taylor a écrit :

See


http://www.ebay.com/itm/LTE-Lite-GPSDO-Evaluation-Kit-with-20MHz-TCXO-/171504586548



Ships World wide for $10 US

Regards,  John K1AE
===

 Well, no.  If I look at that entry from the UK it  says:

 $24.75 USPS Priority Mail International Small  Flat Rate Box

so it's not US $10 worldwide.

 David


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Re: [time-nuts] fast switching quiet synthesizer

[Alan Melia]

Jim I am not sure if this will meet your requirement for hygene but google 
Trinity Power Inc (Bob Yarbrough) he has a unit that was featured in EDN 
some time around a year ago. I doesnt switch fast enough at present but that 
could be altered. the problem might be that I think it is a PLL Rather 
than a DDS. But might be worth a look I know the PTS I have a couple 
of earlier Wavetek- Rockland units ...one TTL and one GPIB also an Adret 201 
which uses the same technique.


Alan
G3NYK


- Original Message - 
From: Jim Lux jim...@earthlink.net
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Tuesday, October 07, 2014 6:02 PM
Subject: [time-nuts] fast switching quiet synthesizer




At work, I'm putting together a multichannel stepped frequency CW radar 
breadboard, and I'm looking for something to serve as a source that I can 
step quickly.
I'm looking at stepping every millisecond or so.  Right now, I use a 
Ardunino type microcontroller driving a serial DAC driving a VCO, but 
that's a bit wonky and noisy, although it's easy to get the step timing 
right on.  The spectral purity is, shall we say, downright ugly.


Since I'm going to be doing precision ranging with this, the spectral 
purity has to be reasonably good (not 1E-15 at 1000 seconds good, 
fortunately)..


I was thinking about a PTS synthesizers  (beloved of time-nuts for all 
kinds of reason), and they're nice because they are quiet, and switch 
really fast (microseconds).  However, they all seem to have BCD or GPIB 
interfaces (only).  Sure, I can code up something on an Arduino or other 
microcontroller to drive the BCD on the PTS, but maybe there's something 
else out there that might work as well?  And is already off the shelf.



I could hook a Prologix on the back of a PTS with GPIB, and hit it over 
the ethernet, but I'm not sure I'd be able to get the steps to occur when 
I want them (ethernet and determinism do not go well together).


Maybe some DDS in a box product?  That will take my nice clean 10 MHz 
reference?


Ultimately, I'm looking at output frequencies in single digit GHz, but 
something that can be mixed/multiplied up will work just fine.


I'm looking for something that is off the shelf-ey as much as possible. 
Using surplus gear is ok, because I really only need 3 or 4 channels and 
that might be scroungeable, but spending hours wiring up weird adapters or 
locating connectors that haven't been made since 1943 is something I'd 
like to avoid.



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Re: [time-nuts] fast switching quiet synthesizer

[Alan Melia]

Hi Don, Jim, that is the one I was refering to, It has a VCO as the source 
(all part of the AD4351) but I think your description of the unit is more 
accurate that mine. Contact him directly he is keen to contact new areas and 
hobbyists. There are two units one is a source with 4 output levels, I 
believe he sells that on eBay at $280 but direct contact may get you a 
better deal. There is a version with a calibrated attenuator but this has FM 
capability which adds to the VCO control and may not be good for PN. I think 
this sells for $340.
Robert Yarbrough  rob...@rf-consultant.com  (blame me for airing his ID 
:-))  )


Alan
G3NYK




- Original Message - 
From: Don Latham d...@montana.com
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Tuesday, October 07, 2014 9:19 PM
Subject: Re: [time-nuts] fast switching quiet synthesizer



I have two versions of the ADF4351 dds. One is the AD eval board, and the
other the TPI synthesizer
(http://www.rf-consultant.com/calibrated-signal-generator/) at $280 that 
might
do the job. The latter device performs well. It will be as good as the 
4351, I
think. It has a programmable attenuator. A good price.  Requires a 
Healthy!

USB port.
Don


Magnus Danielson

You should be able to use DDS test-boards and by timing your last write,
you should be able to time the frequency jump.

The STEL-1173 takes 6 bytes, but writing the last one latches all 6
bytes over to a single 48 bit word. I expect that other DDSes have the
same distinct transfer-phase if you only look in the datasheet for the
details.

Some of the modern DDSes can take 10 MHz directly and step it up
internally before hitting the DDS core, but it may be that you need to
synthesize a higher clock from the 10 MHz first.

Cheers,
Magnus

On 10/07/2014 07:02 PM, Jim Lux wrote:


At work, I'm putting together a multichannel stepped frequency CW radar
breadboard, and I'm looking for something to serve as a source that I
can step quickly.
I'm looking at stepping every millisecond or so.  Right now, I use a
Ardunino type microcontroller driving a serial DAC driving a VCO, but
that's a bit wonky and noisy, although it's easy to get the step timing
right on.  The spectral purity is, shall we say, downright ugly.

Since I'm going to be doing precision ranging with this, the spectral
purity has to be reasonably good (not 1E-15 at 1000 seconds good,
fortunately)..

I was thinking about a PTS synthesizers  (beloved of time-nuts for all
kinds of reason), and they're nice because they are quiet, and switch
really fast (microseconds).  However, they all seem to have BCD or GPIB
interfaces (only).  Sure, I can code up something on an Arduino or other
microcontroller to drive the BCD on the PTS, but maybe there's something
else out there that might work as well?  And is already off the shelf.


I could hook a Prologix on the back of a PTS with GPIB, and hit it over
the ethernet, but I'm not sure I'd be able to get the steps to occur
when I want them (ethernet and determinism do not go well together).

Maybe some DDS in a box product?  That will take my nice clean 10 MHz
reference?

Ultimately, I'm looking at output frequencies in single digit GHz, but
something that can be mixed/multiplied up will work just fine.

I'm looking for something that is off the shelf-ey as much as possible.
Using surplus gear is ok, because I really only need 3 or 4 channels and
that might be scroungeable, but spending hours wiring up weird adapters
or locating connectors that haven't been made since 1943 is something
I'd like to avoid.


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--
The power of accurate observation is commonly called cynicism by those 
who

have not got it.
-George Bernard Shaw

Dr. Don Latham AJ7LL
Six Mile Systems LLC
17850 Six Mile Road
Huson, MT, 59846
mail:  POBox 404
Frenchtown MT 59834-0404
VOX 406-626-4304
Skype: buffler2
www.lightningforensics.com
www.sixmilesystems.com


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Re: [time-nuts] fast switching quiet synthesizer

[Alan Melia]

Jim,
Bob Yarbrough's built units do 50 to 4400MHz, +10dBm and input for external 
10MHz ref signals, though has an internal 10MHz TCXO. It sounds worth a try 
if it can be programmed to step fast enough, min step size is 1kHz (from 
memory).


Alan
G3NYK
- Original Message - 
From: Jim Lux jim...@earthlink.net

To: time-nuts@febo.com
Sent: Wednesday, October 08, 2014 12:36 AM
Subject: Re: [time-nuts] fast switching quiet synthesizer



On 10/7/14, 10:32 AM, Magnus Danielson wrote:

You should be able to use DDS test-boards and by timing your last write,
you should be able to time the frequency jump.

The STEL-1173 takes 6 bytes, but writing the last one latches all 6
bytes over to a single 48 bit word. I expect that other DDSes have the
same distinct transfer-phase if you only look in the datasheet for the
details.



Yes, virtually all of them have a load input of some form (I'm familiar 
with the AD98xx and AD99xx ones, and they certainly do).


What I'd really like, though is something at a slightly higher level of 
integration (for which I am willing to pay.. it's a time vs money thing). 
Does someone sell a DDS in a box with connectors, etc.


I need a tuning range, for now, of around 3.1 to 3.4 GHz, so any of the 1 
GHz DDSes can generate something that I could mix up with a 2.8-3 GHz LO 
(which I have), although I'd have to be careful about images.
Or I can run the few hundred MHz out of the DDS into a doubler/tripler, 
then mix up.





Some of the modern DDSes can take 10 MHz directly and step it up
internally before hitting the DDS core, but it may be that you need to
synthesize a higher clock from the 10 MHz first.
Not a problem, I think I have a 10 in to 100 MHz out set of bricks from 
Wenzel (x5 and x2) from a previous project



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Re: [time-nuts] Diodes as temperature sensors

[ALAN MELIA]

Simple temperature sensors use the static diode characteristic, but a more 
accurate method is to use the slope of the characteristic, this is independent 
of individual diode parameters, though requires a little it more electronics to 
display. There are many papers on this back in the 1960/70s.

Alan
G3NYK





 From: Hal Murray hmur...@megapathdsl.net
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Cc: hmur...@megapathdsl.net 
Sent: Monday, 21 July 2014, 4:58
Subject: Re: [time-nuts] Diodes as temperature sensors
 


alw.k...@gmail.com said:
 Apparently, the forward biased silicon diode was temperature sensitive
 enough that a small D.C. amplifier could drive a meter to read-out with
 reasonable accuracy. Well, maybe not accurate by Time-nut standards but
 close enough for its intended purpose. 

I think that mechanism is widely used for silicon temperature sensors.  There 
is one (or more) on most modern CPU chips as well as special temperature 
measuring chips such as the Maxim/Dallas DS18B20 and DS18S20.


-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] temperature sensor

[Alan Melia]

er not boiling watersteam. Water's boiling point is affected by the 
dissolved gasses and other contaminants.


Alan
G3NYK
- Original Message - 
From: Bill Dailey docdai...@gmail.com
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Monday, July 21, 2014 5:43 PM
Subject: Re: [time-nuts] temperature sensor


Ice water and boiling water coupled with altitude will give you two 
points.


Sent from mobile


On Jul 21, 2014, at 10:12 AM, Attila Kinali att...@kinali.ch wrote:

On Mon, 21 Jul 2014 04:39:51 -0700
Alexander Pummer alex...@ieee.org wrote:


NTC are not that very stable, they are amorphous material winch could
recrystallize slowly and therefore change it's electrical behavior ,
PT100 style is more reliable since it is pure metal


How long is the time constant for NTCs?
I guess, it wouldn't matter for most of the measurements we do,
as NTCs need to be calibrated before precision measurements
anyways. Unless one measures over several months, or years.
But on this timescales, i wouldn't really trust an off the shelf
PT100 either. Not unless i measure its stability

For use in GPSDOs and OCXOs, i guess it doesn't really matter,
as long as the NTC stays within spec. There an external loop
corrects for the variation/drift of the measurement.


While we are at it: what is a good way to calibrate/characterize
temperature sensors that is available to hobbyists?

   Attila Kinali

--
I pity people who can't find laughter or at least some bit of amusement 
in

the little doings of the day. I believe I could find something ridiculous
even in the saddest moment, if necessary. It has nothing to do with being
superficial. It's a matter of joy in life.
   -- Sophie Scholl
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Re: [time-nuts] temperature sensor

[Alan Melia]

Yes but water can be superheated too if there are no nucleation points for 
bubbles to form and like super-cooling this can amount to a couple of deg C 
in a very clean container. However the vapour cannot be superheated without 
increasing the pressure .as in a steam engine, or autoclave. I may not 
be as accurate as temperature nuts would like but unless you are very sure 
of your conditions it is probably more reliable. I notice the wiki on 
temperature scales doesn't include boiling water (or steam) these days, 
but if does say is 17mK low of an exact 100 :-))

http://en.wikipedia.org/wiki/Temperature_scales#International_temperature_scale_of_1990
I note it doesnt actually say where you place the sensor :-))
Alan
G3NYK
- Original Message - 
From: Brooke Clarke bro...@pacific.net
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Monday, July 21, 2014 9:11 PM
Subject: Re: [time-nuts] temperature sensor



Hi:

The temperature of steam can be anything above boiling water.
http://en.wikipedia.org/wiki/Steam

Super heating of steam was common railroad practice.

Boiling pure water will get rid of any trapped gases quickly.
In fact this is the recommended thing to do to tap water before using it 
for freshly cut roses.
Of course you need to let the water cool before putting them into it. 
Removing the trapped oxygen makes them last longer.


Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
http://www.prc68.com/I/DietNutrition.html

Alan Melia wrote:
er not boiling watersteam. Water's boiling point is affected by the 
dissolved gasses and other contaminants.


Alan
G3NYK
- Original Message - From: Bill Dailey docdai...@gmail.com
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Monday, July 21, 2014 5:43 PM
Subject: Re: [time-nuts] temperature sensor


Ice water and boiling water coupled with altitude will give you two 
points.


Sent from mobile


On Jul 21, 2014, at 10:12 AM, Attila Kinali att...@kinali.ch wrote:

On Mon, 21 Jul 2014 04:39:51 -0700
Alexander Pummer alex...@ieee.org wrote:


NTC are not that very stable, they are amorphous material winch could
recrystallize slowly and therefore change it's electrical behavior ,
PT100 style is more reliable since it is pure metal


How long is the time constant for NTCs?
I guess, it wouldn't matter for most of the measurements we do,
as NTCs need to be calibrated before precision measurements
anyways. Unless one measures over several months, or years.
But on this timescales, i wouldn't really trust an off the shelf
PT100 either. Not unless i measure its stability

For use in GPSDOs and OCXOs, i guess it doesn't really matter,
as long as the NTC stays within spec. There an external loop
corrects for the variation/drift of the measurement.


While we are at it: what is a good way to calibrate/characterize
temperature sensors that is available to hobbyists?

   Attila Kinali

--
I pity people who can't find laughter or at least some bit of amusement 
in
the little doings of the day. I believe I could find something 
ridiculous
even in the saddest moment, if necessary. It has nothing to do with 
being

superficial. It's a matter of joy in life.
   -- Sophie Scholl
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Re: [time-nuts] Phase noise and geomagnetism

[Alan Melia]

Hi Antonio you must remember the static geomagnetic field is around 
50,000nT and the biggest Solar induced events are around 500nT  so the 
effect might be difficut to detect as  events of this size are not very 
common.  More common events are in the 100 to 200nT range.


Alan
G3NYK

- Original Message - 
From: iov...@inwind.it

To: time-nuts@febo.com
Sent: Monday, April 28, 2014 10:18 PM
Subject: [time-nuts] Phase noise and geomagnetism


As our geomagnetic field gets quite noisy during geomagnetic storms (which 
are connected to solar activity), I was wondering if this could affect 
phase noise of oscillators. I see that theoretically it could. Has anybody 
ever measured phase noise increments which could be explained this 
way?Antonio I8IOV

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Re: [time-nuts] frequency comparator reading question

[Alan Melia]

These units multiply the frequency delta and the phase change quoted is 
probably 10^n times the actual difference. The output is f + n*delta(f)


I have but do not use a Montronix 100-7 (before the Fluke purchase)
Alan
G3NYK
- Original Message - 
From: Bill Hawkins b...@iaxs.net
To: 'Discussion of precise time and frequency measurement' 
time-nuts@febo.com

Sent: Thursday, February 27, 2014 5:55 PM
Subject: Re: [time-nuts] frequency comparator reading question



The question can't be answered without knowing what the range switch
does.
In my experience, the cycle that is divided into 360 degrees is the
period
of the input signal regardless of the range switch.

You don't say, but the usual GPSDO produces a 10 MHz signal, unless it's
for a telco application. If the phase meter goes through one cycle in a
second
there is a one cps difference between the signals. One cycle at 10 MHz
is
one part in 10E7. One cycle in a kilohertz is 1 part in 1000. 1 cycle in

100 seconds for 10 MHz is one part in 10E9

Does the time for a phase rotation vary with the range switch?

Bill Hawkins

-Original Message-
From: Bob Camp
Sent: Wednesday, February 26, 2014 9:16 PM

Not having one here, about all I can guess is that there are 360 degrees
in a cycle. If it's going through 360 degrees in 10 seconds it's 0.1 Hz
off at what ever point it's comparing.  If it takes 100 seconds that's
0.01 Hz.

Yes I get this pesky decimal point stuff wrong from time to time ...

Bob

On Feb 26, 2014, at 9:19 PM, Paul A. Cianciolo pa...@snet.net wrote:


I have a Fluke montronics frequency comparator.
It has 2 inputs, one from my GPS and one from my DUT.
After a given oscillator is warmed up, I can read the meter in parts
10 -X
There are 2 meters, One for phase 0 to 360 degrees, and one for part
to the -nth
In the 10-9th position on the selector switch the a given oscillator
will show a 0 to 360 degrees travel lets say in 1 second.


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Re: [time-nuts] WWVB antennas

[Alan Melia]

Claims on antenna efficiency at these frequencies are fairly meaningless (as 
always) in that a normal antenna efficiency would be less than 1% !!

Alan
G3NYK

- Original Message - 
From: JIM FARLEY jimfar...@att.net
To: t...@patoka.org; Discussion of precise time and frequency 
measurement time-nuts@febo.com

Sent: Saturday, February 22, 2014 4:28 PM
Subject: Re: [time-nuts] WWVB antennas


Google 'fractal antenna'. Fractal Antennas are a relatively recent (late 
1980's to mid-1990's) discovery/invention. I have read that they are 
approximately 20% more efficient than normal antennas.


Jim, KG4FXV




From: d0ct0r t...@patoka.org
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Saturday, February 22, 2014 12:54 AM
Subject: Re: [time-nuts] WWVB antennas


I am impressed by Casio engineers who created tiny antenna for my wrist 
watch. I don't know how, but that Pathfinder able to catch and decode 60 
khz wwvb in noisy city environment. And it did even better when i was 500 
km north !


:40, Alexander Pummer wrote:

here are the other 60kHz transmitters:
http://www.ka7oei.com/wwvb_antenna.html

U.S. based WWVB transmitter. As described, it
  could also be used for theUK-based 60 kHz MSF
http://en.wikipedia.org/wiki/Time_from_NPL MSF signal formerly
the Rugby clock* *and the
Japanese 60 kHz JJY http://en.wikipedia.org/wiki/JJY_
_our fiend in Australia most likely*_ _*receive the JapaneseWWVB
73
KJ6HUN
Alex
_*//*_






On 2/21/2014 12:21 PM, Robert Roehrig wrote:

John Forster said:

WWVB is hard to detect w/ a 3-foot diameter HP shielded loop w/ 
integral
preamp  2 stages of mechanical filters. (HP 117A). The other half of 
the

time it was undetectable. Paul S uses a loop that is much larger.

I am near Chicago and I have 2 60 kHz antennas. One is a ferrite
rod type and the other a 5 foot diameter loop. Both are tuned
and feed identical 2 transistor preamp. The loop does work better.
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-- WBW,

V.P.
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Re: [time-nuts] Mini Circuits RF TX question

[Alan Melia]

It isnt going to help I guess but WB transformers for 50ohm are usually 
designed with a reactance of 150 ohms (3* termination) at the lowest 
frequency required. It might give an idea where to look?.


Alan G3NYK

- Original Message - 
From: cdel...@juno.com

To: time-nuts@febo.com
Sent: Tuesday, January 28, 2014 6:26 PM
Subject: [time-nuts] Mini Circuits RF TX question



Hi,

Does anyone know where to find the primary inductance value for Mini
Circuits RF Transformers?

I need to know so I can pick one to resonate with a particular capacitor
at 5Mhz.


Thanks,

Corby

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Re: [time-nuts] OT - Old Hatfield 2105 Step attenuator specs

[Alan Melia]

Hi Alberto it is quite interesting to continue that test with no attenuator 
but the shells of the coax plugs connected together. I would guess with the 
gear you have the resultant would be at least 120dB downbut this is 
not the case for all signal generators! The result is usually particularly 
poor with video generators, and often laughable with function generators. 
This is were many LFers get confused calibrating receive equipment.


Alan
G3NYK



- Original Message - 
From: Alberto di Bene dib...@usa.net

To: time-nuts@febo.com
Sent: Wednesday, January 08, 2014 8:50 PM
Subject: Re: [time-nuts] OT - Old Hatfield 2105 Step attenuator specs



On 1/6/2014 2:13 PM, Giuseppe Marullo wrote:


/I would like to know the specs for this attenuator, especially the
maximum frequency, if any good folk has a ballpark idea...
I was not able to locate any info about it./


I too have one, bought cheaply a couple of years ago on eBay. I tested its 
accuracy

with a calibrated RF generator and a Selective Voltmeter, both from WG,
at a frequency of approximately 10 MHz.

Up to roughly 70 - 75 dB attenuation, it is reasonably accurate. Beyond 
that
value, the internal leakages dominates, and you can forget to have an 
attenuation

of 100 dB, when you set it to the maximum...

73  Alberto  I2PHD


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Re: [time-nuts] OT - Old Hatfield 2105 Step attenuator specs

[Alan Melia]

Hi Guiseppi I think I have some papers on them somewhere.I cant remember the 
model numbers. If you are refering to the units in blue crackle diecast case 
with miniature toggle switches the spec max frequency is 150MHz from memory. 
I did plot one some time ago on my Spectrum Analyser and TG, They are usable 
to 200MHz with reduced accuracy.


Alan
G3NYK.
- Original Message - 
From: Giuseppe Marullo giuse...@marullo.it
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Monday, January 06, 2014 1:13 PM
Subject: [time-nuts] OT - Old Hatfield 2105 Step attenuator specs



Hello to all,
and Happy New Year.

I would like to know the specs for this attenuator, especially the maximum 
frequency, if any good folk has a ballpark idea...

I was not able to locate any info about it.

Thanks in advance.

Giuseppe Marullo
IW2JWW
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Re: [time-nuts] OT - Old Hatfield 2105 Step attenuator specs

[Alan Melia]

Hi agn Giuseppi that may indicate your units date from later, after the 
company were acquired by Pascall

Alan
- Original Message - 
From: Giuseppe Marullo giuse...@marullo.it
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Monday, January 06, 2014 4:05 PM
Subject: Re: [time-nuts] OT - Old Hatfield 2105 Step attenuator specs



Alan,
thank you for your answer.
. If you are refering to the units in blue crackle diecast case with
miniature toggle
Sort of, but mine is orange:
http://thumbs3.ebaystatic.com/d/l225/m/mkbCnoRgl8RNnxvJdy9phAw.jpg
Seems pretty close, I was hoping for some better figure but I plan to use 
it for HF bands, so no big deal if the Fmax is 150MHz.


Thank you again.

Giuseppe Marullo
IW2JWW
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Re: [time-nuts] Measuring TV delays

[Alan Melia]

Hi Bill both the 405 line and the 625 line PAL and SECAM systems in Europe 
framed at 25 fpsec prob for the same reason .even though by 625 line 
inception the sets were transistorised often except for the line output 
stage.


A chat to a BBC engineer at NPL Teddington at a Time  Freq Club meeting 
even before UK switched to digital suggested that timing was uncertain as 
the program distribution was being done using digital signals. I believe 
this made interleaving local content easier.

Alan
G3NYK
- Original Message - 
From: Bill Hawkins b...@iaxs.net
To: 'Discussion of precise time and frequency measurement' 
time-nuts@febo.com

Sent: Thursday, January 02, 2014 7:33 PM
Subject: Re: [time-nuts] Measuring TV delays



IIRC, the reason why NTSC has an almost 30 fps rate is that early
vacuum tube TV sets could develop heater-cathode leakage that
would put a black hum bar in the picture. Almost 30 allows the
bar to move through the picture in a 60 Hz power distribution
system. Seems like Europe would have had that problem.

No need for it now, but it's like the QWERTY keyboard . . .

Bill Hawkins


-Original Message-
From: Magnus Danielson
Sent: Thursday, January 02, 2014 12:15 PM

So, in the US and other 3/1001 frames per second countries (formerly

NTSC), encoded time is not going to be useful for precision work. For us

in the 25 frames per second world, we only need to jam for leap-seconds
and DST change-overs, but that is enough of an upset, but can be more
easily predicted with only a few handful of bits extra information.

I prefer using MLS measurement for audio delay measurement. If you do it

right, you get 20,833 us step resolution, as a result of the 48 kHz
sampliung clock. MLS delay measurement is trivial using the Analog
Precision test-set.

Cheers,
Magnus
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Re: [time-nuts] GPS timing antenna 5 meter BNC Plug with cable

[Alan Melia]

Hi David I have no experience of that unit, but I have had several orders 
serviced by them over a couple of years and I have no complaints and their 
customer service (Kiki) is helpful


Alan
G3NYK

- Original Message - 
From: David J Taylor david-tay...@blueyonder.co.uk

To: Time-nuts mailing list time-nuts@febo.com
Sent: Thursday, December 05, 2013 5:56 AM
Subject: [time-nuts] GPS timing antenna 5 meter BNC Plug with cable


Anyone know whether these antennas are any good?  Anyone used one?  I 
wonder where they are made?



http://www.rfsupplier.com/timing-antenna-meter-plug-with-rg58-coax-cable-p-2344.html

Looks like it has no filter, and some of the spelling is dubious!

Thanks,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
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Re: [time-nuts] Problem with site?

[Alan Melia]

My last message arrived at 0559 this morning 22nd Oct
Alan
G3NYK

- Original Message - 
From: Rob Kimberley robkimber...@btinternet.com
To: 'Discussion of precise time and frequency measurement' 
time-nuts@febo.com

Sent: Tuesday, October 22, 2013 12:52 PM
Subject: [time-nuts] Problem with site?



Just a test to see if this site is working, as had no posts since Sunday.

Cheers

Rob Kimberley



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Re: [time-nuts] How hard is it to detect a GPS Jammer?

[Alan Melia]

Many scanners now go to that frequency e.g AOR AR-8600. (100kHz to 2GHz ) 
They are hardly state-of-the-art receivers but should be capable of 
detecting jammers driving past. However a new unit is quite pricey $1000 
equivalent in the UK as little as $300 for a used version. Also the AMSAT 
FCD Pro+ USB SDR at $200 and free software.


Alan
G3NYK

- Original Message - 
From: Bob Camp li...@rtty.us
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Monday, October 07, 2013 12:36 PM
Subject: Re: [time-nuts] How hard is it to detect a GPS Jammer?



Hi

Anything that will receive up there should be able to tell you when a 
jammer comes by. The issue is that not a lot of gear is made for that band 
(other than GPS receivers). The easy approach would be to use a modern GPS 
module that puts out noise level / jamming information.


Bob


On Oct 7, 2013, at 12:59 AM, Hal Murray hmur...@megapathdsl.net wrote:

The recent discussion of solar flares screwing up GPS timing was 
interesting.


I just watched Todd Humphreys TED talk again.  He's focused on location, 
but

does mention time in terms of stock exchanges.
 Todd Humphreys: How to fool a GPS
 http://www.ted.com/talks/todd_humphreys_how_to_fool_a_gps.html

He's got a good discussion of GPS jammers and spoofers, but no geeky 
details.



What's the spectral/power output of the typical eBay GPS jammer?

Suppose I lived near a major highway.  Could I build a receiver that 
would

count jammers driving by?  Could I track them (at least somewhat) with a
directional antenna on a rotator?

Is this something semi-geeky amateurs could contribute to?

What sort of gear has harmonics in the GPS band?

--

I assume people are familiar with the trucker who jammed the FAA test in 
NJ.

Here is a good story:
 http://www.insidegnss.com/node/3676

That article has a link to commercial gear targeted at this market.
 http://www.exelisinc.com/solutions/signalsentry/Pages/default.aspx
The graphics shows 3 receivers is a port/harbor setting.



--
These are my opinions.  I hate spam.



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Re: [time-nuts] exponential+linear fit

[Alan Melia]

I agree a fit to an equation that has no physical meaning is a bit spurious. 
You can fit almost anything to a polynomial, but it doesnt mean that the 
coefficients mean anything or that an interpolation between data points is 
even sensible!! I have been the victim of a clever maths graduate (with no 
physics knowledge!)


Alan
G3NYK


- Original Message - 
From: Tim Shoppa tsho...@gmail.com
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Monday, October 07, 2013 2:03 PM
Subject: Re: [time-nuts] exponential+linear fit



Proposing a random fitting with various curves without an underlying
physical (e.g. Eureqa) model seems... odd. That's more voodoo
engineering/science than anything real. It doesn't surprise me that
computer scientists would propose that as an approach to data, making it
even more inappropriate.

Having well-versed engineers and physical scientists looking at curves and
striving to understand the various features with underlying 
well-understood

and used physical models (including abnormalities in measurements), that
seems appropriate.

The originally proposed model of long term linear drift trend plus
exponential decay of initial thermal conditions is very well understood 
and

accepted.


On Mon, Oct 7, 2013 at 3:46 AM, Ulrich Bangert 
df...@ulrich-bangert.dewrote:



Jim,

most if not all fitting strategies make use of an assumption concerning 
the

underlying model.

For those who are not sure what the underlying model is this one

http://creativemachines.cornell.edu/eureqa

is the hottest tool that I have ever seen. Give it a try.

Best regards

Ulrich

 -Ursprungliche Nachricht-
 Von: time-nuts-boun...@febo.com
 [mailto:time-nuts-boun...@febo.com] Im Auftrag von Jim Lux
 Gesendet: Freitag, 4. Oktober 2013 19:38
 An: Discussion of precise time and frequency measurement
 Betreff: [time-nuts] exponential+linear fit


 I'm trying to find a good way to do a combination
 exponential/linear fit
 (for baseline removal).  It's modeling phase for a moving
 source plus a
 thermal transient, so the underlying physics is the linear term (the
 phase varies linearly with time, since the velocity is constant) plus
 the temperature effect.

 the general equation is y(t) = k1 + k2*t + k3*exp(k4*t)

 Working in matlab/octave, but that's just the tool, I'm
 looking for some
 numerical analysis insight.

 I could do it in steps.. do a straight line to get k1 and k2,
 then fit
 k3 k4 to the residual; or fit the exponential first, then do the
 straight line., but I'm not sure that will minimize the
 error, or if it
 matches the underlying model (a combination of a linear trend and
 thermal effects) as well.

 I suppose I could do something like do the fit on the
 derivative, which
 would be

 y'(t) = k2 + k3*k4*exp(k4*t)

 Then solve for the the k1.  In reality, I don't think I care as much
 what the numbers are (particularly the k1 DC offset) so
 could probably
 just integrate (numerically)

 y'()-k2-k3*k4*exp(k4*t) and get my sequence with the DC term, linear
 drift, and exponential component removed.


 The fear I have is that differentiating emphasizes noise.
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Re: [time-nuts] exponential+linear fit

[Alan Melia]

Hi Joe that sounds like a system I was thinking of suggesting to Jim. I 
wrote some iterative code on a time share bureau machine in the late60s. 
make a guess at kx values and let the prog spit out k values for a dk/dt 
minimum then chose another set of starters an see if it finishes in the 
same place. A given local minimum may not be the lowest. Its crude but very 
effective. My boss didnt believe it and employed a mathematician who did not 
understand the physics to get it wrong ! this was fitting to similar type 
equation an Arhennius equation (if I remembered how to spell him :-))


A friendly mathematician called it the BFI technique

Alan
G3NYK


- Original Message - 
From: Joseph Gwinn joegw...@comcast.net

To: time-nuts@febo.com
Sent: Friday, October 04, 2013 9:18 PM
Subject: Re: [time-nuts] exponential+linear fit



On Fri, 04 Oct 2013 14:30:40 -0400, time-nuts-requ...@febo.com wrote:

--

Message: 4
Date: Fri, 04 Oct 2013 10:38:07 -0700
From: Jim Lux jim...@earthlink.net
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: [time-nuts] exponential+linear fit
Message-ID: 524efcff.8000...@earthlink.net
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

I'm trying to find a good way to do a combination exponential/linear fit
(for baseline removal).  It's modeling phase for a moving source plus a
thermal transient, so the underlying physics is the linear term (the
phase varies linearly with time, since the velocity is constant) plus
the temperature effect.

the general equation is y(t) = k1 + k2*t + k3*exp(k4*t)

Working in matlab/octave, but that's just the tool, I'm looking for some
numerical analysis insight.

I could do it in steps.. do a straight line to get k1 and k2, then fit
k3 k4 to the residual; or fit the exponential first, then do the
straight line., but I'm not sure that will minimize the error, or if it
matches the underlying model (a combination of a linear trend and
thermal effects) as well.

I suppose I could do something like do the fit on the derivative, which
would be

y'(t) = k2 + k3*k4*exp(k4*t)

Then solve for the the k1.  In reality, I don't think I care as much
what the numbers are (particularly the k1 DC offset) so could probably
just integrate (numerically)

y'()-k2-k3*k4*exp(k4*t) and get my sequence with the DC term, linear
drift, and exponential component removed.


The fear I have is that differentiating emphasizes noise.


How many measured data points do you have?  If you have enough data,
you can use the MatLab nlinfit() (nonlinear fit) function to fit the
data directly to the y(t) equation.

Because nlinfit uses a least-squares approach, and there are many
coefficients to be found, a reasonable starting point is required.  The
fit on the derivative, while probably too noisy to yield a useful final
answer, would be one way to get some of the initial values.

I did just this recently, fitting a skew gaussian pdf to a histogram,
using rough mean, standard deviation, and skewness computed from the
histogram to seed nlinfit.  The mean, standard deviation, and skewness
computed from the histogram are famously inaccurate if there is
significant skew, but it was still good enough to keep nlinfit from
getting lost.

Joe Gwinn
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Re: [time-nuts] exponential+linear fit

[Alan Melia]

Jim it may not be helpful but had you thoughtof expanding the exponential as 
the first few terms of an infinite series to see if it simplifies fitting?


Alan
G3NYK

- Original Message - 
From: Jim Lux jim...@earthlink.net

To: time-nuts@febo.com
Sent: Friday, October 04, 2013 10:16 PM
Subject: Re: [time-nuts] exponential+linear fit



On 10/4/13 1:18 PM, Joseph Gwinn wrote:

On Fri, 04 Oct 2013 14:30:40 -0400, time-nuts-requ...@febo.com wrote:

--

Message: 4
Date: Fri, 04 Oct 2013 10:38:07 -0700
From: Jim Lux jim...@earthlink.net
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: [time-nuts] exponential+linear fit
Message-ID: 524efcff.8000...@earthlink.net
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

I'm trying to find a good way to do a combination exponential/linear fit
(for baseline removal).  It's modeling phase for a moving source plus a
thermal transient, so the underlying physics is the linear term (the
phase varies linearly with time, since the velocity is constant) plus
the temperature effect.

the general equation is y(t) = k1 + k2*t + k3*exp(k4*t)

Working in matlab/octave, but that's just the tool, I'm looking for some
numerical analysis insight.

I could do it in steps.. do a straight line to get k1 and k2, then fit
k3 k4 to the residual; or fit the exponential first, then do the
straight line., but I'm not sure that will minimize the error, or if it
matches the underlying model (a combination of a linear trend and
thermal effects) as well.

I suppose I could do something like do the fit on the derivative, which
would be

y'(t) = k2 + k3*k4*exp(k4*t)

Then solve for the the k1.  In reality, I don't think I care as much
what the numbers are (particularly the k1 DC offset) so could probably
just integrate (numerically)

y'()-k2-k3*k4*exp(k4*t) and get my sequence with the DC term, linear
drift, and exponential component removed.


The fear I have is that differentiating emphasizes noise.


How many measured data points do you have?  If you have enough data,
you can use the MatLab nlinfit() (nonlinear fit) function to fit the
data directly to the y(t) equation.



I'm removing a slowly varying bias term from fairly noisy data.  Maybe 
several 10s of thousands of data points,

And I want to do it quickly on a slow processor.





Because nlinfit uses a least-squares approach, and there are many
coefficients to be found, a reasonable starting point is required.  The
fit on the derivative, while probably too noisy to yield a useful final
answer, would be one way to get some of the initial values.


I've done that and it works.. but I'm looking for a more basic sort of 
approach, given that I actually know something about the underlying model.




I did just this recently, fitting a skew gaussian pdf to a histogram,
using rough mean, standard deviation, and skewness computed from the
histogram to seed nlinfit.  The mean, standard deviation, and skewness
computed from the histogram are famously inaccurate if there is
significant skew, but it was still good enough to keep nlinfit from
getting lost.





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Re: [time-nuts] NIST off-line

[Alan Melia]

On Topic I hope Tom :-)) ..I have just used the NIST time server to 
correct a PC clock here in the UK so it cannot all be down ??


Alan
G3NYK
- Original Message - 
From: Tom Van Baak t...@leapsecond.com
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Tuesday, October 01, 2013 9:37 PM
Subject: Re: [time-nuts] NIST off-line



I know it's hard to resist, but...

keep all time-nuts postings, even this thread, strictly related to precise 
time  frequency, please.


/tvb
http://www.leapsecond.com/time-nuts.htm


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Re: [time-nuts] Pulsars make a GPS for the cosmos

[Alan Melia]

There is actually little at 1421MHz from the sun the radiation from the sun 
is black body radiation  1421 is an electron flip more likely in isolated 
molecules (the sun is plasma not gas) or Hydrogen masers. We set up 12Ghz 
sat LNBs a couple of weekends ago to try and stimulate some school interest 
big peak on sat finder. There are storms which generate signals in the 
VHF/ UHF range that can be heard on simple equipment receivers built 
with CBTV front-ends.(tuners)


Pulsars are very weak the flux is measured in Janskys and I get confused 
converting that back to radio values. but a 10m dish at about 600Mhz and you 
should get something on a UHF receiver though you often need something like 
the averaging of a box-car detector. You do need to know which direction to 
look in.


Alan (G3NYK)
Brit Astro Assocn Radio Astro Group

- Original Message - 
From: J. Forster j...@quikus.com
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Sunday, September 29, 2013 12:13 AM
Subject: Re: [time-nuts] Pulsars make a GPS for the cosmos



The sune is hugely bright in the RF.

I've been able to see it at 2.2 GHz with nothing more than a horn a foot
or so across and a receiver w/ a NF of maybe 8 dB (cavity preselector 
mixer  IFA...   ACL SR-209).

There was a noticable difference between pointing at the sun and in
another direction.

During a SETI search, when 80-odd foot dish was pointed at the sun, the
preamp was completely saturated sat about 1421 MHz.

-John

=



Hi

If you are on the surface of the earth, you face the sun from time to
time. That creates some issues that you would not have in a deep space
setting. In deep space you don't have to correct for all sorts of orbital
issues as well. This is one of those - not so easy here - sort of things.

Bob


On Sep 28, 2013, at 6:55 PM, Bob Stewart b...@evoria.net wrote:


Just to satisfy my curiosity: what's easiest to detect galactic pulse
emitter (regardless of type), and what's the minimum setup to reliably
look at it, whether it's just during night time, or whatever.  Just
seeking perspective, I haven't just won the lottery.

Bob
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Re: [time-nuts] FCC politics vs their engineers...

[Alan Melia]

Was it not always so?? Remember the politicians pay the bills not the 
engineers!

Alan
G3NYK

- Original Message - 
From: Eric Williams wd6...@gmail.com
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Tuesday, September 17, 2013 7:04 PM
Subject: Re: [time-nuts] FCC politics vs their engineers...



He tells me with some bitterness that politics triumphed over
all of the objections of the engineering staff to LS and that this
is not the first time that this has happened.

That's how we ended up with Challenger and Columbia.


On Tue, Sep 17, 2013 at 6:46 AM, Michael Baker mp...@clanbaker.org 
wrote:



Time-Nutters--

Jim wrote:
snip
 That's why the FCC granted a conditional waiver
 of the rules.  It was politically expedient, and I would
 imagine that the engineers at the FCC thought there's
 no way they'll be able to demonstrate no interference

Charles wrote:
snip
 The Commission not only thought LS would demonstrate
 non-interference, it put its thumb on the scale until the
 public outcry became too loud to ignore (the GPS interests
 took forever to wake up -- that didn't happen until all of
 the comment periods were long closed).  It just didn't
 matter what the staff engineers thought -- which is
 business  as usual at the FCC.
--**--

A friend of mine was one of the FCC lead supervisory engineers
that was involved in the LS fiasco.  He tells me that there were
technical reports, evaluation summaries and strong opinions
offered by the engineering staff that provided a number of
reasons why the LS project should be denied.  He tells me that
most of these engineering studies got buried and ignored.
He tells me with some bitterness that politics triumphed over
all of the objections of the engineering staff to LS and that this
is not the first time that this has happened.

Mike Baker
Gainesville, FL  USA

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Re: [time-nuts] Lightning Strike Site, Latency of AS3935 IRQ output

[Alan Melia]

:-))  sorry Tom I couln't resist the dig but it looks like the result was 
interesting and a little unexpected ! its always better to measure it 
yourself, where possible,  than rely on datasheets which can sometimes be 
quite imaginative


Well done
Alan
- Original Message - 
From: Tom Bales t...@starhouse.org

To: time-nuts time-nuts@febo.com
Sent: Monday, September 16, 2013 6:21 PM
Subject: [time-nuts] Lightning Strike Site, Latency of AS3935 IRQ output



Alan,

Well, you shamed me into actually setting it up and measuring the IRQ
delay.  Amazingly, the delay varies from 25 to 110 milliseconds, depending
upon what type of triggering is involved.  I did the test using their
lightning simulator and measuring the delay between the magnetic pulse
the simulator creates and switching of the IRQ line.  Makes you wonder 
what

a little processor could possibly be doing for a whole tenth of a second.

Tom Bales


Message: 3
Date: Tue, 10 Sep 2013 00:34:49 +0100
From: Alan Melia alan.me...@btinternet.com
To: Discussion of precise time and frequency measurement
   time-nuts@febo.com
Subject: Re: [time-nuts] Lightning Strike Site (Jim Lux)
Message-ID: EF06D912BDF74BE6BE916C3088B7F68B@gnat
Content-Type: text/plain; format=flowed; charset=iso-8859-1;
   reply-type=response

Come on fellas it can't be that difficult to input a pulse to the chip and
measure the prop delay to the INT pin this is timenuts after all :-))

Alan
G3NYK
- Original Message -
From: Jim Lux jim...@earthlink.net
To: time-nuts@febo.com
Sent: Tuesday, September 10, 2013 12:08 AM
Subject: Re: [time-nuts] Lightning Strike Site (Jim Lux)



On 9/9/13 3:52 PM, Mark Sims wrote:

The AS3935 has an INT output pin that signals a detection.   You could
monitor that.  The AS3935 is based upon an internal DSP processing the
receiver output.  No telling how long between when the strike occurs and
when INT is activated.


I'd send a nice note to the folks in Austria who make the part and ask
them.

I suspect, also, that you might be able to figure out some other 
lightning

sensor electronics: the Boltek unit wasn't all that complex, looking at
the PC board, but I didn't have a schematic.



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Re: [time-nuts] Lightning Strike Site (Jim Lux)

[Alan Melia]

Come on fellas it can't be that difficult to input a pulse to the chip and 
measure the prop delay to the INT pin this is timenuts after all :-))


Alan
G3NYK
- Original Message - 
From: Jim Lux jim...@earthlink.net

To: time-nuts@febo.com
Sent: Tuesday, September 10, 2013 12:08 AM
Subject: Re: [time-nuts] Lightning Strike Site (Jim Lux)



On 9/9/13 3:52 PM, Mark Sims wrote:
The AS3935 has an INT output pin that signals a detection.   You could 
monitor that.  The AS3935 is based upon an internal DSP processing the 
receiver output.  No telling how long between when the strike occurs and 
when INT is activated.


I'd send a nice note to the folks in Austria who make the part and ask 
them.


I suspect, also, that you might be able to figure out some other lightning 
sensor electronics: the Boltek unit wasn't all that complex, looking at 
the PC board, but I didn't have a schematic.




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Re: [time-nuts] sub-minute time-precision in court-case

[Alan Melia]

I remember a lecture by an officer of the (London) Met Police about how 
tracable time was essential to demolishing the defence of wrong clock  in 
accidents involving the illegal use of mobile phones when moving and even 
parking meter tickets. They had to argue why the cell time was more right 
than the defendants watch!! This was part of a meeting of the Time and 
Frequency Club at the NPL at Teddington about 6 years ago.


Alan
G3NYK

..
- Original Message - 
From: Mike S mi...@flatsurface.com

To: time-nuts@febo.com
Sent: Tuesday, September 03, 2013 5:19 PM
Subject: Re: [time-nuts] sub-minute time-precision in court-case



On 9/3/2013 10:56 AM, Jim Lux wrote:


In this case, all the messages were presumably handled by the same
carrier, so the issue of skew in timestamps is negligible; they're all
presumably running off the same clock.


But not necessarily the same time. For instance, some cell systems run on 
GPS time, but the carrier may keep records in UTC, since it's the legal 
time in most jurisdictions. A phone might time stamp using either (Google 
has a years-old bug in Android which lets it use GPS time and not UTC). 
So, different devices on the same network may not be in sync.




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Re: [time-nuts] Halcyon OFS-1 Circuit Diagram or Manual?

[Alan Melia]

Hi Mike I have had a Halcyon OFS-1 for 20 years and been looking for a 
manual/circuit during that time. Mine was bought from Halcyon and came with 
an A4 sheet of paper !Not alignment instructions!! I have been looking 
for detail ever since. I would certainly be interested to see a copy of the 
alignment instructions.


I very nearly ripped mine apart several years ago when I found the output 
phase breathing with a period of about 100 seconds. After double checking 
my local standards and using another receiver, I contacted Peter Whibberly 
at NPL and they had not seen it because they integrate over a much longer 
period to get parts in 10^12. I was put in touch with an engineer at 
Droitwich, he looked but didnt find anything wrong (they did not have an 
off-air standard!) However the problem improved at the time of the 
inpection -))  Subsequently I got an email from Peter about 6 weeks later 
saying that the synthersizer had failed completely !!  After the repair the 
phase drift against my local standard was much better and probably at the 
limit of short term daytime off-air measurementI couple of parts in 
10^11


My case is a cream textured finish in two identical parts. The rear panel 
has a ferrite antenna hinged to it, though an expernal antenna can be used. 
I believe some of the later units locked an ovened oscillator and contained 
a dil-switch set synthersizer to generate quasi-synch carrier frequencies. 
It may be you have an OFS pcb out of one of these that has been recased??


Best Wishes
Alan
G3NYK

- Original Message - 
From: Mike Niven mfni...@ymail.com

To: time-nuts@febo.com
Sent: Thursday, August 22, 2013 4:16 PM
Subject: [time-nuts] Halcyon OFS-1 Circuit Diagram or Manual?


I have acquired an old working 198kHz/162kHz off-air frequency standard that 
appears to be a Halcyon OFS1 circuit board mounted in a DIY case. I think 
this since
it came with a sheet of alignment instructions from Halcyon which certainly 
ties
up with the PCB layout but the case is not made to professional standards. 
So, nice enough

looking, but with no manufacturer's logo or model number to really identify
it.

If it is an OFS1, would anybody have a circuit diagram or manual to enable 
me to confirm my theory? I can't find very much on the web about Halcyon 
products as the company is long gone.


Many
thanks.

Mike
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Re: [time-nuts] How quartz crystals are (were) fabricated

[Alan Melia]

all crystals would have been subject to X-rays to some extent because this 
was how the planes were located and the cutting angles determined. The dose 
rate was probably quite low in this case.I dont remember seeing much 
protection around the machine in the lab I worked in.


Alan
G3NYK

- Original Message - 
From: Charles P. Steinmetz charles_steinm...@lavabit.com
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Thursday, August 01, 2013 2:52 PM
Subject: Re: [time-nuts] How quartz crystals are (were) fabricated



Bob wrote:

The X-Ray process does nothing good to the crystal. It's impact is highly 
dependent on how dirty the crystal is.


Bob,

Do you have authoritative references for this proposition?  If not, can 
you identify what data and what inferences it is based on?


I could imagine the X-ray process relieving stress in the crystal (perhaps 
to advantage), or disrupting the crystal structure (likely detrimental). 
I'm interested to know if anyone has researched this in a systematic way 
and, if so, what they found.  (My intuition favors the disruption 
hypothesis over stress relief, but I'm much more interested in research 
and data than in intuition or speculation.)  Data on other forms of 
radiation would also be interesting, if research has been done.  (We 
already know that heat can be beneficial, at least in certain 
circumstances, so I'm not so interested in that at the moment.)


Of course, when the X-ray technique was developed most crystals were not 
housed in evacuated holders, so atmospheric and environmental factors were 
larger contributors (at least to aging) than they are today.  That could 
have obscured researchers' ability to discriminate the effects of the 
X-ray treatment in contemporaneous testing.


Best regards,

Charles




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Re: [time-nuts] How quartz crystals are (were) fabricated

[Alan Melia]

Hi Charles yes I didn't actually run the videowas saving it for later 
:-))  this suggests bond disruption is being used. Like  musical string if 
you stiffen the  material the resonant frequency should drop. One can only 
guess this is what might be happening. The lab I was working in (though not 
on crystals) was producing high quality standards for BC and telecoms, and 
was part of the then Post Office Engineering Department of Research branch. 
I never heard of that method (X-rays) for trimming crystals mentioned. This 
is probably because they were not a bulk manufacturer. The more usual method 
they used was to plate for a little longer in the vacuum evaporation 
stage.easy on one-offs :-)) the WWII 10XJ and FT243 (or was it FT241?) 
were not plated and you can only raise their frequency by lapping. The Ham 
method with soft lead pencil (or drafting ink) would not be allowed!.


Alan
- Original Message - 
From: Charles P. Steinmetz charles_steinm...@lavabit.com
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Thursday, August 01, 2013 4:54 PM
Subject: Re: [time-nuts] How quartz crystals are (were) fabricated



Alan wrote:

all crystals would have been subject to X-rays to some extent because this 
was how the planes were located and the cutting angles determined. The 
dose rate was probably quite low in this case


Right.  The film that Alberto posted a link to also showed (beginning at 
35:30) a procedure that Reeves Sound Labs devised to lower the frequency 
of a crystal after final testing, using a powerful beam of X-rays that 
alter[s] certain properties of the quartz itself.  The jig looks to have 
quite a bit of lead shielding, although I thought they could have sealed 
the gap around the sliding drawer somewhat better (it does appear to be a 
redundant seal).


Best regards,

Charles




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Re: [time-nuts] WWVB odd propagation 07/14/2013

[Alan Melia]

Hi Paul a major geomag storm occured around midnight UTC on the 14/15th. 
This precipitated hot electrons into the D-region which causes extra 
attenuation at night and enhanced daytime long distance signals. The daytime 
effect is usually short lived but the night-time absorbtion may continue for 
a few nights, as the ionoshere exchanges charge with the Ring Current (Van 
Allen belts)


Alan
G3NYK

- Original Message - 
From: paul swed paulsw...@gmail.com

To: paul swed paulsw...@gmail.com; Time-nuts time-nuts@febo.com
Sent: Monday, July 15, 2013 2:56 AM
Subject: [time-nuts] WWVB odd propagation 07/14/2013



Well this is pretty strange.
Working on the WWVB d-psk-r and testing a new simple receiver with agc.
Classic transistor design simple, cheap, and common parts.

Normal wwvb signal strength on near boston using a Dymec WWVB rcvr quite
accurate.
daynight
60-80 300-500

today
150150

Fairly constant and we have gone through diurnal shift across the country
now.
Thats very strange
Also verified using a HP3586 and its readings have matched the Dymecs
throughout the day.
The agc is not getting much of a work out. But I have to say I have never
seen wwvbs signal this stable and I am talking many years.
Regards
Paul
WB8TSL
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Re: [time-nuts] What is the deal with li...@lazygranch.com

[Alan Melia]

Hi Doug what software are using as your mail client, and under what OS. I 
have had similar effects on an older system. I seem to get the lists 
postings ok.


Alan
G3NYK

- Original Message - 
From: Doug Calvert dfc-l...@douglasfcalvert.net
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Tuesday, June 18, 2013 9:00 PM
Subject: [time-nuts] What is the deal with li...@lazygranch.com



Time Nuts,
Is something messed up on my end with mail from li...@lazygranch.com?
I seem to get an iawful lot of blank emails from this address to the
t-n list.
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Re: [time-nuts] What is the deal with li...@lazygranch.com

[Alan Melia]

Yes it's not you Doug I think he has a  problen, in the archive for June he 
has two blank messages then a message titled test. So guess he is sorting 
it.
I get fat-finger syndrome sometimes and hit send button instead of the 
button to the left (delete) :-))
Alan 


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Re: [time-nuts] Ground loops in measurements?

[Alan Melia]

Hi Bob whats the problem at low freqs ?? I thought leakage was a function of 
the size of the holesv the wavelengthor are we into braid skin effect 
below 100kHz?? so as not to drag this OT a reference will suffice in answer.


Best Wishes
Alan G3NYK
- Original Message - 
From: Bob Camp li...@rtty.us
To: 'Discussion of precise time and frequency measurement' 
time-nuts@febo.com

Sent: Monday, May 20, 2013 6:00 PM
Subject: Re: [time-nuts] Ground loops in measurements?



Hi

Coax is interesting stuff. The shielding is only good down to some lower
frequency limit. For anything practical that's going to be  100 KHz.

At the frequencies you *should* use coax at, transformer coupling is the
easy way to break the ground loop. In this era of cell phones all over the
place, a transformer plus some sort of common mode choke is the standard
approach.

For things like 1 pps, you should be using some sort of balanced
transmission. Twisted pair, or better, shielded twisted pair. You can 
either

run into a balanced receiver IC and dc couple or into a transformer and do
something a bit fancier. With the IC you have a maximum voltage offset 
that
can be tolerated. With the transformer you have the cost / delay / 
possible

error in picking up the edges.

If your environment is noisy enough, you may have to transport your pps on
some sort of carrier. RF and optical both have their fans.

None of that is going to be easy. The alternative is to do what you would 
do
in a screen room. Single point ground, everything tied tightly together. 
Put
reasonable filtering on everything in and out. Tie the filters to the 
common
ground point. This also is not easy, but possibly not as hard as 
redesigning

the ins and outs of every box in sight. I have seen this approach used on
some *very* large systems.

A some what extreme approach (that I have seen used). Forget about all the
shielding and stuff. Buy a farm, put up a small metal shack in the middle 
of

a large field. Bring a hand cart with batteries. Run everything on a big
copper covered table.

Lots of ways to go.

Bob



-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Attila Kinali
Sent: Monday, May 20, 2013 8:08 AM
To: time-nuts@febo.com
Subject: [time-nuts] Ground loops in measurements?

Moin,

A couple of weeks ago, there was a short discussion on bad connectors
and cables and the coupled in noise of those. Summarized it said that
measurements in the time-nuts scale are very sensitive to even the lowest
noise levels and coupled in signals.

But, all the measurements we do are done using some sort of coax which
have their shield connected to the case of the devices. As the invovled
devices in a measurement are also grounded over their power supply
this will lead to ground loops and thus a 50/60Hz noise. Also, because
loops are good magnetic antennas, a lot of other noise floating around
in the ether is coupled in (eg a nearby radio station).

How do you handle this kind of problems?

Attila Kinali

--
The people on 4chan are like brilliant psychologists
who also happen to be insane and gross.
-- unknown
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Re: [time-nuts] OCXO Adjustment Question

[Alan Melia]

I use this method too, but I also find it little use trying to get the 
internal reference down to the last squeak in 10^11 on this kind of kit. It 
will not hold the setting for vey long and it takes ages to get the 
adjustment spot on. I get as close as I can easily.then allow the 
unknown to stabilise and do an estimate of the error and stick a label with 
thay value on the front until the next check is required  eg 2 in 10^9 high 
6thApr13 ..would not suit an avid time-nut but then the equipment is 
often barely time-nut quality :-))


Alan G3NYK

.
- Original Message - 
From: Bill Riches bill.ric...@verizon.net
To: 'Discussion of precise time and frequency measurement' 
time-nuts@febo.com

Sent: Wednesday, May 08, 2013 11:52 AM
Subject: Re: [time-nuts] OCXO Adjustment Question



This is the method I use for my 5110. There are two 10 mhz outputs on the
osc - you can unplug one of the plugs and use a 10x probe there. My unit
will hold a couple  of parts in
10-8 for months.

73,

Bill, WA2DVU
Cape May, NJ

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of J. L. Trantham
Sent: Tuesday, May 07, 2013 11:52 PM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] OCXO Adjustment Question

Fred,

What I do is to apply the GPSDO to the trigger input of a scope and the
output of the OCXO to be adjusted to the vertical input of the scope.  Set
the time base to something line 100 nSec or faster and watch the output of
the OCXO after it has warmed up for 30 minutes or so.

This is an option only if you have an output from the OCXO you can watch.
If no output, try a x10 probe attached to a 10 MHz connection from the 
OCXO
inside the monitor.  However, be careful that the probe does not 'load' 
the

OCXO and shift the frequency.

Adjust the OCXO for a stable display, not drifting left or right.

If the sine wave (or square wave) is moving to the left, the OCXO is high 
in
frequency.  If it is moving to the right, the OCXO is low in frequency. 
If
stable, it is matched to the GPSDO.  This is useful as long as the OCXO 
and

GPSDO are within a few Hz of each other.  The amount of time it takes for
the display to shift 1 cycle tells you how close the OCXO is to the GPSDO.

For instance, if it takes 10 seconds for the display to shift one cycle,
100,000,000 +/- 1 cycles went by in that 10 seconds or 1 part in 10E9 if I
have my math correct.

Joe

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Frederick Bray
Sent: Tuesday, May 07, 2013 9:25 PM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] OCXO Adjustment Question

This might be slightly off-topic, but probably there is a time-nut who 
knows

the answer.

I am trying to adjust the 10 MHz OCXO in a Cushman 5110 service monitor. 
I
am using a frequency counter driven by a GPSDO.  Perhaps someone can 
educate

me about a couple problems I am encountering.

I tried making small incremental adjustments but after I am done, the
frequency drifts several Hz and then re-stabilizes at a new value.  When I
make further adjustments, I notice strange behavior. For example, if I
initially turned the adjustment clockwise to increase the frequency, it 
will

now decrease if I turn it clockwise and increase if I turn it
counter-clockwise.  On the next adjustment, it will reverse again.

Is there some correct procedure to adjust an OCXO?

Many thanks for any suggestions.

Fred Bray
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Re: [time-nuts] Italian Time Station on 10 MHz ?

[Alan Melia]

Hi Marco maybe you should run a web site with daily measurements and shame 
them into doing it properly ( your traceable to NIST  should raise some 
hackles !!) I took me four months to get a short term wander on 198kHz 
looked at a few years ago. I was cured when the synth finally failed 
completely ! The private contractor did not have at the time any way of 
measuring it off-air, despite taking the NPL money for running it. :-))


Alan
G3NYK

- Original Message - 
From: Marco IK1ODO -2 ik1...@spin-it.com
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Sunday, April 28, 2013 9:25 PM
Subject: Re: [time-nuts] Italian Time Station on 10 MHz ?




For what I know they have an experimental license by the Telecom 
authority, and operate from Tuscany near Viareggio since two or three 
years. The license has been given on the basis that there are no more HF 
time and frequency signals operating in Europe.
When I knew about it I offered to donate a rubidium standard, to have it 
at least on the right frequency.
I had no answers... they continue to radiate a worthless off-frequency 
signal (IMHO). May be it is a case of beaconitis :-) (a disease that 
mandates to activate beacons).
On a similar base, I know of an attempt to restore and put in operation 
the old transmitter of IBF (5 MHz, Istituto Nazionale di Elettrotecnica, 
now INRIM, the national standard keepers). That was a custom built 5 kW 
(carrier) Continental broadcasting TX. It has been found in the 
underground storage of INRIM, stripped of power and modulation 
transformers, and should be rebuilt to operate at only 1 kW carrier on the 
original 5 MHz frequency (Rb or GPS controlled!). The plans are to operate 
it from the original place on the hills near Torino, by remote control, as 
a museum and educative item. I offered my workshop to work on it, I hope 
that the project may go on to again hear IBF, IBF, IBF, standard time and 
frequency signals from the National Electrotechnical Institute, Turin, 
Italy from minutes 45 to 60 on 5 MHz ;-)


Marco IK1ODO / AI4YF


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Re: [time-nuts] Brooks Shera ASM release

[Alan Melia]

Ok Bert I will stick my head above the parapet and repeat that 
query.Sometimes it is frustarting the get no response, but later get 
personal appreciation as you meet individuals. I didn't know the guy. I was 
trying with a friend to contact him long after the original article. We were 
disapointed but not unhappy. I certainly appreciate the help and expertise 
the Group provides..and it is nice to be able to say so, and salute the 
work Brooks did.


Thanks and Best Wishes
Alan Melia
(G3NYK)
- Original Message - 
From: ewkeh...@aol.com

To: time-nuts@febo.com
Sent: Monday, April 15, 2013 8:17 PM
Subject: Re: [time-nuts] Brooks Shera ASM release



Alan
You may suggest something to time nuts, looking at the response I doubt it
and ask my self why did three of us spend three weeks to fully check it 
out

and  fix some of the code. Will reflect future projects.
Bert Kehren


In a message dated 4/12/2013 8:39:40 P.M. Eastern Daylight Time,
alan.me...@btinternet.com writes:

Bert is  there any way we can add our names to some expression of thanks 
to

his  widow Karen and her helpers for their work and maybe leave a
remembrance
of his worldwide friends for his family?

Thanks for your  efforts
Best wishes
Alan Melia  (G3NYK)
UK


-  Original Message - 
From: ewkeh...@aol.com

To:  time-nuts@febo.com
Sent: Friday, April 12, 2013 8:52 PM
Subject:  [time-nuts] Brooks Shera ASM release



The time-nuts server  takes out all spaces so allow me to  resend the
 acknowledgementsBert Kehren
 
  


At this time I like to thank  Brooks for all  the work he did, his wife
Karen Stoll for  deciding to release HEX and ASM and  Bob Leichner who
implemented  the software commands. Brooks did not have the  chance to

put

 final
touches in and complete his work, so Richard McCorkle   stepped in and

made

the
final changes. For almost a decade  Brooks and Richard  collaborated on

the

GPSDO, which benefits all  of us. Also major recognition has  to go to
Juerg
Koegel  an other time nut that put our other projects on hold to  check
 every
iteration. Attached is part of a test that clearly shows  the

performance

of
the Alpha filter. Limited by  attachment size contact me off list  for

more

data.
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Re: [time-nuts] Brooks Shera ASM release

[Alan Melia]

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

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

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

Alan Melia (G3NYK)  Ipswich, UK

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Re: [time-nuts] Brooks Shera ASM release

[Alan Melia]

Bert is there any way we can add our names to some expression of thanks to 
his widow Karen and her helpers for their work and maybe leave a remembrance 
of his worldwide friends for his family?


Thanks for your efforts
Best wishes
Alan Melia  (G3NYK)
UK


- Original Message - 
From: ewkeh...@aol.com

To: time-nuts@febo.com
Sent: Friday, April 12, 2013 8:52 PM
Subject: [time-nuts] Brooks Shera ASM release



The time-nuts server takes out all spaces so allow me to  resend the
acknowledgementsBert Kehren
  
  


At this time I like to thank Brooks for all  the work he did, his wife
Karen Stoll for deciding to release HEX and ASM and  Bob Leichner who
implemented the software commands. Brooks did not have the  chance to put 
final
touches in and complete his work, so Richard McCorkle  stepped in and made 
the

final changes. For almost a decade Brooks and Richard  collaborated on the
GPSDO, which benefits all of us. Also major recognition has  to go to 
Juerg
Koegel an other time nut that put our other projects on hold to  check 
every
iteration. Attached is part of a test that clearly shows the  performance 
of

the Alpha filter. Limited by attachment size contact me off list  for more
data.
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Re: [time-nuts] Low-pass Filter for 5 and 10 MHz

[Alan Melia]

Maybe a silly question but isnt the phase response of the filter important 
in this application ?? notches have fairly vicious phase shifts.


Alan
G3NYK
- Original Message - 
From: Luciano Paramithiotti timeok...@gmail.com

To: time-nuts@febo.com
Sent: Thursday, April 11, 2013 5:42 PM
Subject: [time-nuts] Low-pass Filter for 5 and 10 MHz



A simple low pass filter to cut second and third harmonics from a 5 or 10
MHZ signal.
See the paper:
http://www.timeok.it/files/5_and_10mhz_low_pass_notch_filter.pdf

Luciano Timeok
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[time-nuts] GPS antenna??

[Alan Melia]

Hi all an interesting problem you may have encountered, I want to use a GPS 
frequency standard inside a building with no opening windows (opening 
windows are known as air conditioning in the UK :-))  )
This is part of a two day amateur microwave conference so we should have the 
expertise.


I intend to try and pass the signal through a a double glazed glass window 
unit (hopefully not metalised) using a couple of patch antennas. The outer 
GPS antenna is active so will need  a 5v supply via an inserter. Inner patch 
active, outer patch passive to avoid problems of feedback. Main antenna can 
be shielded from the coupling either physically or with a slab of 
absorber.


Has anyone tried this? does it work?.any gotchas?

Thanks
Alan
G3NYK 


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Re: [time-nuts] GPS antenna??

[Alan Melia]

Hi Bob yes it is South facing.I may have todo that anyway because the 
window may be too far above ground level (the land slopes away from the 
ground entrance.. pity I had totally forgotten that.


Thanks
Alan
G3NYK

- Original Message - 
From: Bob Camp li...@rtty.us
To: 'Discussion of precise time and frequency measurement' 
time-nuts@febo.com

Sent: Monday, April 08, 2013 8:28 PM
Subject: Re: [time-nuts] GPS antenna??



Hi

Is the proposed window south facing? If not, you will need enough cable
outdoors to get your second antenna to a south facing location.

Assuming it's south facing and reasonable sky view, have you tried a patch
antenna on / at the window? That should at least give you some idea of how
likely the signal is to get through it. It's not uncommon to run GPSDO's
with window mounted antennas.

Bob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Alan Melia
Sent: Monday, April 08, 2013 1:00 PM
To: time-nuts measurement
Subject: [time-nuts] GPS antenna??

Hi all an interesting problem you may have encountered, I want to use a 
GPS

frequency standard inside a building with no opening windows (opening
windows are known as air conditioning in the UK :-))  )
This is part of a two day amateur microwave conference so we should have 
the


expertise.

I intend to try and pass the signal through a a double glazed glass window
unit (hopefully not metalised) using a couple of patch antennas. The outer
GPS antenna is active so will need  a 5v supply via an inserter. Inner 
patch


active, outer patch passive to avoid problems of feedback. Main antenna 
can

be shielded from the coupling either physically or with a slab of
absorber.

Has anyone tried this? does it work?.any gotchas?

Thanks
Alan
G3NYK

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Re: [time-nuts] GPS antenna??

[Alan Melia]

Hi Tom yes I have produced some similar plots I think they get cold feet 
about 70deg N. I'm not sure of the actual value it is a long time since I 
played with that last.

Alan
- Original Message - 
From: Tom Van Baak t...@leapsecond.com
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Monday, April 08, 2013 9:19 PM
Subject: Re: [time-nuts] GPS antenna??



Aren't GPS birds all over the sky. South facing is for the Clarke belt.


Well, mostly all over, but with higher probability facing up, east, west, 
and towards the equator compared to significant black hole towards the 
pole. For example, see the GPS reception sky map of John's TBolt: 
http://ke5fx.com/heather/readme.htm


For those of you down under, the hole is south rather than north, of 
course.


/tvb

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Re: [time-nuts] GPS antenna??

[Alan Melia]

Hi David yes its ferro-concrete which makes quite a good screen (a lot worse 
than domestic brick) but the windows are not coated I think. (BT Labs at 
Martlesham)


Thanks all for some thought stimulating ideas .GPSDO outside might not 
be too easy1U rack case mains poweredno power available outside but 
10MHz (or 5MHz in this case) coupling through wall or window is a lot easier 
if I had a battery powered unit.I have a feeling there may be battery 
back-up terminals on it must get the book out.


The windows are SW I think but give a good view of a quadrant of the sky. It 
will be interesting to see how long it takes to lock up compared with an 
outside antenna.


Thanks and Best Wishes
Alan
G3NYK



- Original Message - 
From: David J Taylor david-tay...@blueyonder.co.uk

To: time-nuts measurement time-nuts@febo.com
Sent: Monday, April 08, 2013 7:46 PM
Subject: Re: [time-nuts] GPS antenna??


Hi all an interesting problem you may have encountered, I want to use a 
GPS

frequency standard inside a building with no opening windows (opening
windows are known as air conditioning in the UK :-))  )
This is part of a two day amateur microwave conference so we should have 
the

expertise.

I intend to try and pass the signal through a a double glazed glass window
unit (hopefully not metalised) using a couple of patch antennas. The outer
GPS antenna is active so will need  a 5v supply via an inserter. Inner 
patch
active, outer patch passive to avoid problems of feedback. Main antenna 
can

be shielded from the coupling either physically or with a slab of
absorber.

Has anyone tried this? does it work?.any gotchas?

Thanks
Alan
G3NYK
===

Alan,

Here I am on the top floor of a standard house, and get an adequate signal 
for today's GPS receivers with simple patch antennas.  One GPS I have is 
in a walk-in cupboard adjacent to a north-facing outside wall.  Obviously, 
there are no guarantees, but you may get away with just being adjacent to 
an outside wall, or getting the puck near the non-opening window (but that 
may be worse than the wall).


If it /must/ be a GPS relay like you are suggesting, perhaps for multiple 
receivers inside a room, I can't help.  Be sure to place the puck on an 
appropriate ground plane - I find a clean, unused baking tray to be 
perfect!


73,
David GM8ARV
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
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Re: [time-nuts] GPS antenna??

[Alan Melia]

Hi Tom Ah I didnt realise there were such beastsI probably have not the 
time left now but it is one to consider.
Yes I might have to watch the patch polarisation. I did consider two L-band 
waveguide transitions at one stage but thought that might be going too far 
:-)) I thought of the on-glass antenna used in the days of The Brick on 
mobile cellular, or amateur and commercial 2-way radios.


Thanks again for the ideas.

Alan
G3NYK
- Original Message - 
From: Tom Van Baak t...@leapsecond.com
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Monday, April 08, 2013 10:12 PM
Subject: Re: [time-nuts] GPS antenna??



Alan,

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


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


/tvb

- Original Message - 
From: Alan Melia alan.me...@btinternet.com

To: time-nuts measurement time-nuts@febo.com
Sent: Monday, April 08, 2013 9:59 AM
Subject: [time-nuts] GPS antenna??


Hi all an interesting problem you may have encountered, I want to use a 
GPS

frequency standard inside a building with no opening windows (opening
windows are known as air conditioning in the UK :-))  )
This is part of a two day amateur microwave conference so we should have 
the

expertise.

I intend to try and pass the signal through a a double glazed glass 
window
unit (hopefully not metalised) using a couple of patch antennas. The 
outer
GPS antenna is active so will need  a 5v supply via an inserter. Inner 
patch
active, outer patch passive to avoid problems of feedback. Main antenna 
can

be shielded from the coupling either physically or with a slab of
absorber.

Has anyone tried this? does it work?.any gotchas?

Thanks
Alan
G3NYK



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Re: [time-nuts] Releasing sources (was Re: Brooks Shera)

[Alan Melia]

Hi John Please dont take it down! remember there are more of us who quietly
appreciate sites like yours. I once suggested to a query the answer was in
the help file and background by googling or using wikipedia, and was told it
was a lot easier and quicker to play dumb and ask.!!

I also suggest you do as some do and say This is not a beginners project.
If you do not understand the requirements or have the construction skills,
please dont expect support for a freebie

It prob wont stop it but it will give your a clearer conscience when you 
decline to reply :-))

Alan
G3NYK
- Original Message - 
From: NeonJohn j...@neon-john.com

To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Thursday, March 28, 2013 6:16 PM
Subject: [time-nuts] Releasing sources (was Re: Brooks Shera)





On 03/25/2013 09:36 AM, Jim Lux wrote:


One reason is that if one DOES release source, one will wind up
supporting it, because generally, we all nice people and helpful, and
it's hard to tell someone no when they send an email asking how to get
it to compile on Version N+3 when you used version N, etc.  This can be
a real distraction from whatever else you are doing.


Boy, you can say that again.  And open source hardware is even worse.  A
couple of years ago I put up an open source induction heater on my site.
Everything included - schematics, board layouts, CAD files, theory of
operation, how to wind the transformer - in short, everything I could
think of.  There's even a kit available from Fluxeon.com.

Yet I probably spend an hour a day responding to emails about that
project.  Approximately 100% of the questions are either answered on my
site or by a little googling.  It's getting to be enough of a burden
that I'm considering taking the page down.

I'm a dedicated supporter of Open Source but this experience has
tempered my enthusiasm a bit.


And then there's the folks who argue with you about your implementation
or coding style.


Or electrical design style.  I think that the people who want to argue
design, especially what if I did this? type arguments are more
tiresome than the software know-it-alls.

People need to really think and do their Google homework before hitting
the email button on a project site.

John


--
John DeArmond
Tellico Plains, Occupied TN
http://www.fluxeon.com  -- THE source for induction heaters
http://www.neon-john.com-- email from here
http://www.johndearmond.com -- Best damned Blog on the net
PGP key: wwwkeys.pgp.net: BCB68D77
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Re: [time-nuts] Don't use cheap cables -- a cautionary tale

[Alan Melia]

Some of the older synchronised signal generators (2-box systems) e.g 
Marconi, used TNC connectors with solid coax where signal leakage was likely 
to be a problem.

Alan G3NYK
- Original Message - 
From: Volker Esper ail...@t-online.de

To: time-nuts@febo.com
Sent: Sunday, March 03, 2013 6:49 PM
Subject: Re: [time-nuts] Don't use cheap cables -- a cautionary tale




Yes, we all have to learn that lesson...

At the time I use bedea RG-223 and Belden H155 with soldered and crimped 
Telegaertner BNC connectors as general purpose cable (up to 2 GHz). Above 
that frequency I wouldn't use BNC. If you simply connect your tracking 
generator with the spectrum analyzer by using such a BNC cable there's not 
one that is absolutely stable when stressing the connector. I tried 
several manufacturers, HP, Suhner, Radiall, Rosenberger, it's always the 
same.


To make precise measurements I prefer screwed connectors like N or SMA.

Volker


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Re: [time-nuts] PTS 3200 remote programming

[Alan Melia]

Hi Iban well my knowledge of the older generation is not much use to you 
:-)) still I always think any response will bring more comments out of the 
woodwork even if only to correct the false impressions. The suggestion of 
of a faulty chip on that remote digit sounds like a worthwhile way to go.


Good Luck with it these are useful units if a bit big by modern standards.
Best Wishes
Alan
G3NYK

- Original Message - 
From: Iban Cardona icard...@gmail.com
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Saturday, March 02, 2013 12:37 AM
Subject: Re: [time-nuts] PTS 3200 remote programming



Hi Alan,

thanks for answer. Yes I have the manual, but the latches on my pts
not are as are showed in the user manual. Maybe my unit it is a
different version or release, or have some customozation from the pts
guys.

In myunit, I tested the SO-2005 module that is that generates the
100Mhz decade, and I tested manually the 4bit to generate the 800Mhz
and works well.

My unit dont have front panel, only can be controllated remotelly.

The differences from the user manual, is that un the user manual the
1ghz and 100mhz decade shares latch, and in my unit the shares latch
the 100mhz with the 10mhz. The 1ghz latch is shared by the 1hz decade.

Best regards

73! Iban
eb3frn


On Fri, Mar 1, 2013 at 8:27 PM, Alan Melia alan.me...@btinternet.com 
wrote:
Hi Iban do you have a manual? they are available. From memory because its 
a

while since I worked on my Wavetek- Rockland unit I believe the remote
programming is in parallel with the front panel switches. The reason for
raising this is that there may be a problem on the back of the panel
switches.mabe a wire off. Does the 800Mhz front panel switch setting
work correctly ??

Alan
G3NYK

- Original Message - From: Iban Cardona icard...@gmail.com
To: time-nuts@febo.com
Sent: Friday, March 01, 2013 6:42 PM
Subject: [time-nuts] PTS 3200 remote programming



Hi,

I'm traying to use to program the bcd interface of a PTS 3200.

My truble us tha the 100Mhz decade 8 value bit is ignored by the PTS,
then if I send 800Mhz to the PTS dont get output, and if send 900Mhz
then I get 100Mhz.

I checked the unit and the hardware looks OK. And my code is working
well in another PTS units like the 620.

The 3200 have some trick?

Thanks for all

73! Iban
eb3frn
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Re: [time-nuts] PTS 3200 remote programming

[Alan Melia]

Hi Iban do you have a manual? they are available. From memory because its a 
while since I worked on my Wavetek- Rockland unit I believe the remote 
programming is in parallel with the front panel switches. The reason for 
raising this is that there may be a problem on the back of the panel 
switches.mabe a wire off. Does the 800Mhz front panel switch setting 
work correctly ??


Alan
G3NYK

- Original Message - 
From: Iban Cardona icard...@gmail.com

To: time-nuts@febo.com
Sent: Friday, March 01, 2013 6:42 PM
Subject: [time-nuts] PTS 3200 remote programming



Hi,

I'm traying to use to program the bcd interface of a PTS 3200.

My truble us tha the 100Mhz decade 8 value bit is ignored by the PTS,
then if I send 800Mhz to the PTS dont get output, and if send 900Mhz
then I get 100Mhz.

I checked the unit and the hardware looks OK. And my code is working
well in another PTS units like the 620.

The 3200 have some trick?

Thanks for all

73! Iban
eb3frn
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Re: [time-nuts] OT - USB to LPT Adapter - Does it exist?

[Alan Melia]

I dont have the reference in front of me but it might just be worth checking 
the article archive for the Elektor magazine.I have a vague feeing I 
might have seen something there. Many of their past projects have used the 
LPT as a programmable port. There should be an article index on their web 
site I think.


Alan
G3NYK

- Original Message - 
From: J. L. Trantham jlt...@att.net
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Friday, January 11, 2013 1:09 PM
Subject: [time-nuts] OT - USB to LPT Adapter - Does it exist?



Not sure where to ask this question but thought I would start here.



Is there a way to connect a parallel port to a computer via USB?  Not a
device that shows up as 'USB Print Support' but, instead, shows up in 
Device

Manager as an LPT port?  I have been able to do it via PCMCIA to Parallel
Port adapters but I have never found a USB device that would do this.



My goal is to connect a parallel port chip programmer via USB but the
software only looks for LPT ports.  It works with PCMCIA to parallel port
adapters but I haven't solved the puzzle yet with a USB connected device.



Thanks in advance.



Joe

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Re: [time-nuts] eLoran for GPS backup

[Alan Melia]

Hi Chuck, It never went off!! The French are spear-heading this. An 
experimental eLoran station was run from Rugby (GBR site) before it finally 
closed then the gear was relocated to be run by VT Communications, now 
Babcock I believe, based on Anthorn (south bank of the Solway Firth). This 
uses the gear that was originally destinded for Loop Head in Ireland (but 
cancelled due to local protest) as the 3rd slave on the Lessay chain. 
Anthorn is not ideal but it was already a Mil VLF (19.6kHz) site. The 
original experiment was mounted from Trinity House, the Lights an Nav 
authority for the UK, at their base in Harwich just across the river from 
me. The French have attempted to resurect the Mediteranean chain but have 
had no interest. Most of the financers of the Baltic Sylt chain do not seem 
enthusiastic but it remains on (I believe subsidised by the French)


Alan
G3NYK
- Original Message - 
From: Chuck Forsberg WA7KGX N2469R c...@omen.com

To: ExTek gatesja-l...@eskimo.com; time-nuts time-nuts@febo.com
Sent: Wednesday, January 09, 2013 8:04 AM
Subject: [time-nuts] eLoran for GPS backup



The Brits are turning their Loran system back on to protect against GPS
outages from jamming or space weather:

http://www.gpsworld.com/uk-switches-on-eloran-for-backup-in-the-english-channel/

--
 Chuck Forsberg WA7KGX   c...@omen.com   www.omen.com
Developer of Industrial ZMODEM(Tm) for Embedded Applications
  Omen Technology Inc  The High Reliability Software
10255 NW Old Cornelius Pass Portland OR 97231   503-614-0430


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Re: [time-nuts] YIG oscillators

[Alan Melia]

Hi Daniel, I cant remember the reference the web site might help but there 
have been at least a couple of articles on YIG modules in VHF Comms magazine

Alan G3NYK
- Original Message - 
From: Daniel Mendes dmend...@gmail.com
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Friday, January 04, 2013 2:19 PM
Subject: [time-nuts] YIG oscillators




Hi, maybe this topic is a bit boundary for this list, but i´ll just ask
for general directions

I´ve discovered these wonderfull bits of hardware called YIG (Yttrium
iron garnet) Oscillators (and filters!) in Ebay. If someone doesn´t know
what i´m talking about, they are very broadband tunnable oscillators and
filters. Now, the questions:

1) Does someone has some good references about them?

2) Can I get them new from somewere in decent prices or just collect the
trash from ebay? (as most of our Rubudium, OCXOs, Thunderbolts, etc)

Thank you for any help...

Daniel

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Re: [time-nuts] time-nuts Digest, Vol 101, Issue 152

[Alan Melia]

Volker.look at the subject line, the posting is in your hands, you dont 
need to just use the reply button, as somone did with a digest which 
forked the thread.. This means all the posing under Digest are hidden 
from view and searching. You can edit the subject line but this does not 
always return to the old thread if you use he reply button. I think it 
depends on the mail client.

Alan
G3NYK
- Original Message - 
From: Volker Esper ail...@t-online.de
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Saturday, December 22, 2012 8:44 PM
Subject: Re: [time-nuts] time-nuts Digest, Vol 101, Issue 152




Plot 1: MDEV of the time interval reported by GPSDO
Yes, Said, that are important issues.

By the way: I'm now writing in two threads, I don't know, why the original 
thread (Z3805A cooling requirements?) was splitted... Can we please move 
to the original thread?


I am sure, that the noise of the GPSDO PPS-TI data is much to high to 
recognize the effects. I'm going to make a new setup, where I'll compare 
the GPSDO PPS with an external oscilator, e.g. an HP 10544 or the high 
stability reference within my SMX signal generator.


Volker


Am 22.12.2012 05:07, schrieb Said Jackson:

Hi Volker,

What is being plotted here? Efc? Time interval as reported by the GPSDO? 
External counter versus a stable reference?


It looks like the resolution is approaching 10ns/s (1E-08 at 1s), and 
that the short term effects may be hidden in this noise?


The effects are clearly visible in your first GPSCon plot, not sure if we 
can see the short term noise in these plots..


The 10811 I had tested went from ~3E-012 at 100s to ~2E-011 when the fan 
was on, I think both values are quite a bit below the noise floor of your 
plot so probably hard to measure.


Bye,
Said

Sent from my iPad

On Dec 21, 2012, at 6:47 PM, Volker Esperail...@t-online.de  wrote:


Said,

Unfortunately I don't have the equipment to measure the phase noise of 
an HP 10811 (yet).


But I did some work on evaluating the results of my fan experiment. 
Within this posting you'll find two diagrams. The first (named 
1_DF9PL...) shows five MDEV curves (Modified Allan Deviation), each of 
them measured at different times. Total time span is 30.5 hours.


At small tau values (up to 1000 s) only a slight increase of sigma over 
time can be noticed. However, at a tau of 5000 s or greater you can 
watch sigma making a big bump. Ok, that's what we expected before.


In diagram no. 1 it's somewhat fussy to recognize the change of a 
particular sigma(tau). Now, that we've got curious, we want to see, how 
the sigma(tau) changes over time. So I've been providing a second 
diagram (2_...), where sigma(tau) is a function of the time.


You can see, for example, the curve of tau=20480s developing a big hump, 
and falling back to a proper value after about 1800 minutes. All curves 
at a tau greater or equal 2560 do so.


At smaller values the curves are esentially less affected, but - they 
are not back at their starting value after 1800 minutes (30 hours)! You 
could guess, that the hump moves up to longer times with increasing 
sigma - but it doesn't. There is something significantly different below 
tau=2560s.


1 hour ago, I switched off the fan and laid back the aluminium cover. We 
wait and see.


And now, dear time nuts, it's time to go to bed.

Volker




Am 21.12.2012 18:53, schrieb Said Jackson:

Mark,

Your plot still shows excursions of +/-1E-010, about 100x higher base 
noise than the Z3801A/Z3805A are capable of achieving. Wonder where 
that noise is coming from? This noise is probably much higher than the 
thermal effects.


The original post was the question does my Z380xA have reduced 
stability if I add a fan or similar, I think the answer is shown to be 
yes.


Volker, I wonder if you also see fan-induced spurs in the phase noise 
from 1Hz to 100Hz. I would not be surprised if the fan vibration adds 
significant spurs to the 10811A crystal.


Bye,
Said

Sent from my iPad

On Dec 21, 2012, at 9:42 AM, Mark Spencermspencer12...@yahoo.ca 
wrote:


This plot should show the frequency change more clearly.   (Same data 
just presented differently.)


It seems to me that the noise goes may be going down a bit for a 
minute or so just after the fan is turned on but I don't believe these 
plots provide conclusive evidence of this.



Regards
Mark Spencer

Message: 7
Date: Fri, 21 Dec 2012 09:27:29 -0800
From: Said Jacksonsaidj...@aol.com
To: Discussion of precise time and frequency measurement
 time-nuts@febo.com
Cc: Discussion of precise time and frequency measurement
 time-nuts@febo.com
Subject: Re: [time-nuts] Z3805A cooling requirements?
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Great plots guys!

Looking at these results I think my original claim still
holds: ADEV goes up when a fan is involved versus no fan,
even on a double oven