[ARC5] ARC5 Digest, Vol 143, Issue 1 receiver drift tests
Paddy Ryan
pei7cn at eircom.net
Tue Dec 1 06:31:58 EST 2015
thanks Bob..nice results from the S3B and the others close enough..the S38
will be interesting,hi!
73 de Pat/EI7CN
-----Original Message-----
From: arc5-request at mailman.qth.net
Sent: Tuesday, December 01, 2015 5:23 AM
To: arc5 at mailman.qth.net
Subject: ARC5 Digest, Vol 143, Issue 1
Send ARC5 mailing list submissions to
arc5 at mailman.qth.net
To subscribe or unsubscribe via the World Wide Web, visit
http://mailman.qth.net/mailman/listinfo/arc5
or, via email, send a message with subject or body 'help' to
arc5-request at mailman.qth.net
You can reach the person managing the list at
arc5-owner at mailman.qth.net
When replying, please edit your Subject line so it is more specific
than "Re: Contents of ARC5 digest..."
Today's Topics:
1. Re: Second Receiver Drift Test from KE6F SWAN 600R (Brian)
2. Re: Second Receiver Drift Test from KE6F SWAN 600R
(millerke6f at aol.com)
3. Re: Third Receiver Drift Test from KE6F Collins 75S3B
(millerke6f at aol.com)
4. Spreadsheet record of BC-221 drift over a period of some
hours. (Leslie Smith)
5. BC-221 - drift and thermal stability. (also in receivers)
(Leslie Smith)
----------------------------------------------------------------------
Message: 1
Date: Tue, 1 Dec 2015 13:06:36 +1100
From: "Brian" <brianclarke01 at optusnet.com.au>
To: <millerke6f at aol.com>, <wrcromwell at gmail.com>,
<arc5 at mailman.qth.net>
Subject: Re: [ARC5] Second Receiver Drift Test from KE6F SWAN 600R
Message-ID: <A474D237532D4B9EB025CEACB7E20267 at BrianPC>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Hello Bob,
I applaud your efforts and your generosity in sharing your results.
Thermal engineering can be quite tricky. The thermal mass of these radios
you're testing is not just a single number. There are all sorts of pathways
from hot places - sources - to sinks: via radiation, conduction and
convection. So, I would expect many differently shaped frequency vs
temperature over time curves during the course of a day. As you have already
noticed, the relationship with time is not linear. I suspect you are using
time as a substitute variable for temperature.
When I was designing oscillators, I attached RTDs all over the place and
tracked frequency vs temperature over very long time periods - like several
days. I came to the conclusion that there is no such thing as a uniform
change in frequency with temperature, nor a simple rise in temperature to a
plateau. When I came to test ovenised frequency standards (and generators) -
doesn't that tell my age? I found some of the best, in terms of long-term
frequency stability vs ambient temperature, were in HP counters and Collins
synthesised sets, eg, PRC-47. At one stage I had a Marconi signal generator
(2000 series?) that I set up one morning to zero-beat against WWV; this was
in anticipation of a sale that evening. I left the generator on till later
in the afternoon. After an hour, there had been no drift. I came back some 6
hours later; I listened for a zero beat. I could hear nothing. Initially, I
thought it had drifted a long way off frequency. Then I turned the frequency
dial a little and there was the tell-tale whoop - it had stayed on zero beat
the whole time. I was sad to see it go. But it was a big bugger for which I
needed to do my knee-bend exercises for a week before lifting it.
You have chosen a particular order for your tests. What happens when you
revisit, say, the 80 m and 40 m measurements after the 10 m measurements?
What happens if you start with the 10 m measurements?
On Tuesday, December 01, 2015 6:35 AM, you said:
<snip>
Thank you kindly for the comments though and it's fun doing this stuff and
allows me to putter aorund with my test gear.
73 Bob, KE6F
------------------------------
Message: 2
Date: Mon, 30 Nov 2015 21:39:52 -0500
From: millerke6f at aol.com
To: brianclarke01 at optusnet.com.au, wrcromwell at gmail.com,
arc5 at mailman.qth.net
Subject: Re: [ARC5] Second Receiver Drift Test from KE6F SWAN 600R
Message-ID: <1515b6915d3-9af-fcba at webprd-a108.mail.aol.com>
Content-Type: text/plain; charset=utf-8
Hi and thank you for your response and commentary. Very useful
As to the order of testing. Going into this project the assumption was that
the higher frequencies would be a much larger challenge for receivers that
use a variable LO in the first conversion so it does bias the findings a bit
by doing the low frequencies band first and allowing for a longer warm up
and heat soak for the upper bands. It's a question of time usage (mine I am
afraid) but i figure it's still useful data as long as I post the testing
conditions and timing and use the same criteria for all radios in the test
queue.
I just finished the testing of my Collins 75S3B receiver. Interesting
observations will be posted with that post
73
Bob, Ke6F
-----Original Message-----
From: Brian <brianclarke01 at optusnet.com.au>
To: millerke6f <millerke6f at aol.com>; wrcromwell <wrcromwell at gmail.com>; arc5
<arc5 at mailman.qth.net>
Sent: Mon, Nov 30, 2015 6:06 pm
Subject: Re: [ARC5] Second Receiver Drift Test from KE6F SWAN 600R
Hello Bob,
I applaud your efforts and your generosity in sharing your results.
Thermal engineering can be quite tricky. The thermal mass of these radios
you're testing is not just a single number. There are all sorts of pathways
from hot places - sources - to sinks: via radiation, conduction and
convection. So, I would expect many differently shaped frequency vs
temperature over time curves during the course of a day. As you have already
noticed, the relationship with time is not linear. I suspect you are using
time as a substitute variable for temperature.
When I was designing oscillators, I attached RTDs all over the place and
tracked frequency vs temperature over very long time periods - like several
days. I came to the conclusion that there is no such thing as a uniform
change in frequency with temperature, nor a simple rise in temperature to a
plateau. When I came to test ovenised frequency standards (and generators) -
doesn't that tell my age? I found some of the best, in terms of long-term
frequency stability vs ambient temperature, were in HP counters and Collins
synthesised sets, eg, PRC-47. At one stage I had a Marconi signal generator
(2000 series?) that I set up one morning to zero-beat against WWV; this was
in anticipation of a sale that evening. I left the generator on till later
in the afternoon. After an hour, there had been no drift. I came back some 6
hours later; I listened for a zero beat. I could hear nothing. Initially, I
thought it had drifted a long way off frequency. Then I turned the frequency
dial a little and there was the tell-tale whoop - it had stayed on zero beat
the whole time. I was sad to see it go. But it was a big bugger for which I
needed to do my knee-bend exercises for a week before lifting it.
You have chosen a particular order for your tests. What happens when you
revisit, say, the 80 m and 40 m measurements after the 10 m measurements?
What happens if you start with the 10 m measurements?
On Tuesday, December 01, 2015 6:35 AM, you said:
<snip>
Thank you kindly for the comments though and it's fun doing this stuff and
allows me to putter aorund with my test gear.
73 Bob, KE6F
------------------------------
Message: 3
Date: Mon, 30 Nov 2015 22:27:42 -0500
From: millerke6f at aol.com
To: arc5 at mailman.qth.net, bob.nash1 at gmail.com
Subject: Re: [ARC5] Third Receiver Drift Test from KE6F Collins 75S3B
Message-ID: <1515b94dfeb-9af-fe7d at webprd-a108.mail.aol.com>
Content-Type: text/plain; charset=utf-8
Hi and here are the results of the third test of vintage receiver drift
performance. Once again the test conditions are about the same as the
previous two receivers. The signal source is an Agilent E4400B signal
generator with an ovenized clock and calibrated against my Rubidium
standard. The ambient temperature at the time of the test was monitored and
stayed pretty much around 58 degrees F. The test receiver has been in my
collection for quite a while and has been in dry storage but not operated
for at least 10 years. it is in good condition and all functions work
properly. Of special note: The receiver frequency did exhibit a pulling of
around 70 Hz when the RF gain control as set to maximum. I kept this in
mind all through the testing to ensure that the input signal level had no
effect on the frequency. While i used an input level of 500 microvolts on
the two units prior to this test, I ran this test at 100 microvolts to guard
against oscillator pulling.
80 Meters (Ambient Temperature 58 degrees F)
1:10 pm 3.750000 MHz (Start of run)
1:20 pm 3.750085 MHz (85 Hz change)
1:30 pm 3.750119 MHz (34 Hz change)
1:45 pm 3.750132 MHz (13 Hz change)
2:00 pm 3,750155 MHz (23 Hz change)
40 Meters (Ambient temperature 58 degrees F)
2:01 pm 7.150000 MHz (Start of run)
2:15 pm 7.150058 MHz (58 Hz change)
2:30 pm 7.150053 MHz (-5 Hz change)
2:45 pm 7.150055 MHz (2 Hz change)
3:00 pm 7.150067 MHz (12 Hz change)
20 Meters (Ambient temperature 58 degrees F)
3:04 pm 14.200000 MHz (Start of run)
3:18 pm 14.200005 MHz (5 Hz change)
3:36 pm 14.200001 MHz (-4 Hz change)
3:45 pm 14.200001 MHz (no change)
4:00 pm 14.200001 MHz (no change)
15 Meters (Ambient temperature 59 degrees F)
4:03 pm 21.250000 MHz (Start of run)
4:15 pm 21.250041 MHz (41 Hz change)
4:30 pm 21.249980 MHz (-61 Hz change)
4:45 pm 21.249973 MHz (-7 Hz change)
5:00 pm 21.249066 MHz (-7 Hz change)
10 Meters (Ambient temperature 59 degrees F)
5:06 pm 28.500000 MHz (Start of run)
5:22 pm 28.500006 MHz (6 Hz change)
5:40 pm 28.500008 MHz (2 Hz change)
6:00 pm 28.500010 MHz (2 Hz change)
The results above suggest that the 75S3B needs a bit more heat up time than
the prior receivers. The Frequency pulling with the RF gain control with a
fairly high level signal injections (100 microvolts) may be a maintenance
problem, but keeping that problem at bay during the tests should mitigate
those effects. Overall this S line receiver lives up to the Collins
reputation of being a fairly solid performer stability wise and especially
on the upper bands where the crystal controlled front end show's its
superior performance. However, the NC303 and the Swan 600R are certainly
competitive units in frequency stability on the lower bands.
Next unit will be my HQ 129 Hammarlund if I can find it out in the Conex
Followed by my grandson's S38 hallicrafters.
73
Bob, KE6F
------------------------------
Message: 4
Date: Tue, 01 Dec 2015 15:54:49 +1100
From: Leslie Smith <vk2bcu at operamail.com>
To: Ian Wilson <ianmwilson73 at gmail.com>, "ARC-5 List"
<arc5 at mailman.qth.net>
Subject: [ARC5] Spreadsheet record of BC-221 drift over a period of
some hours.
Message-ID:
<1448945689.1765822.454300473.3D719600 at webmail.messagingengine.com>
Content-Type: text/plain; charset="UTF-8"
Hello Ian!? I can do better than "summarize" the drift characteristics.
I can send the spread-sheet!
73 de Les Smith? vk2bcu at operamail.com
On Tue, Dec 1, 2015, at 13:12, Ian Wilson wrote:
> Hi Les,
>
> Don't have access to the yahoo group. Could you summarize the drift
> characteristics? I have informally noted that once a BC-221/LM has
> been on for about 1/2 hr, you only need to breathe on the frequency
> setting to zero beat with 10.000MHz once an hour or so.
>
> 73, ian K3IMW
>
>
> On Mon, Nov 30, 2015 at 1:36 PM, Leslie Smith
> <vk2bcu at operamail.com> wrote:
>> G'day list-readers,
>>
>> I measured the frequency of a BC-221 heterodyne frequency meter over
>> an afternoon, in 2006. I posted the result in the Yahoo Group files
>> for the Yahoo group ARC5-radio.? See BC-221, frequency stability.XLS
>>
>> For more detail about the record, move your mouse pointer over
>> cell A1.
>>
>> I reproduce the content of that cell here: 2006/09/17? <- date of
>> observation. Notes about measurement of freq drift in BC-221
>> hetrodyne freq. meter.
>>
>> (1) Measuring instrument:? Fluke 1912A Multi counter.? (see note 1
>> for more detail)
>> (2) Condition of BC-221.? Ser. # not given here.? The instrument is
>> believed to be in original condition; the set has not been re-
>> capped (to my knowledge).
>> (3) Environment.? Results reported here were recorded by connection
>> the Fluke to the output of the BC-221.? Manual record was made,
>> the table was transcribed to this spreadsheet by hand.
>>
>> Gen Obs.? Since the measurements were made in spring, the minimum
>> freq. observed at 15:30 is consistent with the warmest part of the
>> day.? From this I infer the main cause of drift may be temperature -
>> althought one might also explore the possibility that the minimum
>> coincides with some fluctuation in mains supply.
>>
>> Note 1.? Condition of Fluke frequency meter.? I purchased this second-
>> hand.? The circumstances of the purchase lead me to believe it had
>> been used in a laboratory, then - I presume - discarded due to age,
>> as that is the fate of most laboratory gear.? A manual came with
>> the meter.? There is has no calibration history available to me.
>> The manual does state the worst case expected drift - due to
>> crystal aging.
>>
>>
>>
>>
>>
--
>>
73 de Les Smith
>> vk2bcu at operamail.com
>>
>>
--
>> http://www.fastmail.com - Email service worth paying for. Try it for free
>>
>>
______________________________________________________________
>>
ARC5 mailing list
>>
Home: http://mailman.qth.net/mailman/listinfo/arc5
>>
Help: http://mailman.qth.net/mmfaq.htm
>>
Post: mailto:ARC5 at mailman.qth.net
>>
>>
This list hosted by: http://www.qsl.net
>>
Please help support this email list: http://www.qsl.net/donate.html
--
http://www.fastmail.com - The way an email service should be
------------------------------
Message: 5
Date: Tue, 01 Dec 2015 16:23:38 +1100
From: Leslie Smith <vk2bcu at operamail.com>
To: arc5 at mailman.qth.net
Subject: [ARC5] BC-221 - drift and thermal stability. (also in
receivers)
Message-ID:
<1448947418.1777910.454307417.75F330C6 at webmail.messagingengine.com>
Content-Type: text/plain
Hello List,
About thermal stability.
I don't have the experience Brian reports, but I can say, with great
certainty, that he is correct when he writes, "Thermal engineering can
be tricky." I built several VFO's and plotted the result of freq. vs
temperature, and freq vs time (diurnal). I did this over several days,
and left the window of my workshop open during winter, so I could
measure the temperature at 6AM - at the coldest time of day. After that
I began stacking "cold bricks" around my VFO's and - after that -
recorded the drift vs temperature as the bricks melted.
I got "weird" shaped graphs at the extremes - where a temperature
reversal took place.
It took some time before I understood the cause for clover-leaf shapes
in my graphs. Here is my understanding: Each component has a
temperature coefficient, and the temperature gradient across each
component in a box is different. This is why builders who report that
packing white "beans" into a VFO box does wonders for short term
stability.
When Brian writes "there are all sorts of [thermal] pathways from hot
places ... " he is certainly correct.
This is what I measured in gear I built. If you take Brian's words "can
be tricky" to mean "weird" - then he's correct!
As a corollary to this: When some-one writes they built a V.F.O. that
was so stable it "stayed zero beat for hours" when left in an open box
near a window - I know they are 'messing with my mind'. When some-one
writes that the Colpitts circuit or the Vackar circuit is very stable,
then I know they were lucky in choosing (at random) a set of components
that had some degree of corresponding thermal matching. In other words,
they were lucky. (Or - alternately - the fellow had no idea of the
meaning of stability, or how to measure it.)
My results - measurement in the drift of the BC-221 - may be reliable
(or not reliable). I measured the frequency with a Fluke 1912-A
counter. It was some decades old and not calibrated (to my knowledge.)
I have no idea whether I measured drift in a Fluke 1912-A counter or in
the BC-221.
At the same time I got some idea of the performance of respected gear
with respect to frequency.
I thought the result was worth the effort. Maybe I'll build one or two
crystal oscillators, pack them in a box with beads and see what the
Fluke tells me about them.
--
73 de Les Smith
vk2bcu at operamail.com
On Tue, Dec 1, 2015, at 13:06, Brian wrote:
> Hello Bob,
>
> I applaud your efforts and your generosity in sharing your results.
>
> Thermal engineering can be quite tricky. The thermal mass of these radios
> you're testing is not just a single number. There are all sorts of
> pathways from hot places - sources - to sinks: via radiation, conduction
> and
> convection. So, I would expect many differently shaped frequency vs
> temperature over time curves during the course of a day. As you have
> already noticed, the relationship with time is not linear. I suspect you
> are
> using time as a substitute variable for temperature.
>
> When I was designing oscillators, I attached RTDs all over the place and
> tracked frequency vs temperature over very long time periods - like
> several
> days. I came to the conclusion that there is no such thing as a uniform
> change in frequency with temperature, nor a simple rise in temperature to
> a plateau. When I came to test ovenized frequency standards (and
> generators) - doesn't that tell my age? I found some of the best, in
> terms of long-term
> frequency stability vs ambient temperature, were in HP counters and
> Collins synthesized sets, eg, PRC-47. At one stage I had a Marconi signal
> generator (2000 series?) that I set up one morning to zero-beat against
> WWV; this
> was in anticipation of a sale that evening. I left the generator on till
> later in the afternoon. After an hour, there had been no drift. I came
> back
> some 6 hours later; I listened for a zero beat. I could hear nothing.
> Initially,
> I thought it had drifted a long way off frequency. Then I turned the
> frequency dial a little and there was the tell-tale whoop - it had stayed
> on zero
> beat the whole time. I was sad to see it go. But it was a big bugger for
> which
> I > needed to do my knee-bend exercises for a week before lifting it.
>
> You have chosen a particular order for your tests. What happens when you
> revisit, say, the 80 m and 40 m measurements after the 10 m measurements?
> What happens if you start with the 10 m measurements?
>
> On Tuesday, December 01, 2015 6:35 AM, you said:
>
> <snip>
>
> Thank you kindly for the comments though and it's fun doing this stuff
> and allows me to putter aorund with my test gear.
>
> 73 Bob, KE6F
>
> ______________________________________________________________
> ARC5 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/arc5
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ARC5 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
--
http://www.fastmail.com - Send your email first class
------------------------------
Subject: Digest Footer
_______________________________________________
ARC5 mailing list
ARC5 at mailman.qth.net
http://mailman.qth.net/mailman/listinfo/arc5
------------------------------
End of ARC5 Digest, Vol 143, Issue 1
************************************
More information about the ARC5
mailing list