- Original Message -
From: d0ct0r t...@patoka.org
To: time-nuts@febo.com
Sent: Sunday, March 02, 2014 12:54 AM
Subject: [time-nuts] FSCM 38243 Power Distribution Module
Does anybody knows if FSCM 38243 8-way P/D module is suitable for 10MHZ
frequency ? The module I have, has no
From the construction and components used it isn't UHF ;-) It appears to be 7
two way splittters in series and the transformers look to have plenty of turns.
As you have a 10MHz source why not just try it out? You should get about 9dB
attenuation input to output with the other ports terminated
Yes, there is some satisfaction is measuring to fine tolerances. Of
all the physical measurements we can take, frequency can be measured
with the most accuracy.You say 1ppb is enough.Let's see a
billion is 1E9. A 10Mhz signal is 1E7 cycles per second 9-7 is 2.
You can get to 1ppm
In a message dated 02/03/2014 02:07:05 GMT Standard Time,
bob91...@yahoo.com writes:
All this is very interesting. However, my interest is frequency. In
other words, I want to know that my standard oscillators are as close to
desired frequency as possible, and how close that turns out to
My opinion: For 1ppm you will need any reasonable GPS receiver that
has a 1PPS output. You can find them that are really good and put the
Chris,
I agree investing in a cheap GPS receiver is a good step for anyone playing
with time frequency. I would recommend the same.
But I'd like to
Hi
When you say “adjust crystals close” do you mean:
1) Grinding / plating crystal blanks? (as in fabricating crystals from scratch)
2) Setting uncompensated crystal oscillators on frequency? (as in some radios)
3) Calibrating the OCXO that is the master reference for an instrument?
That all
Hi
It’s a 10 MHz box from the look of it. Everything looks like it’s in the right
place and nothing is broken. It should be good for at least 100 mw into it. It
will have at least 9 db of loss just from the power splitting. If you want 7
dbm out of it, you will need at least 16 dbm into it.
Hi
Assuming you are after a reference at 10 ppb accuracy:
10 ppb would be a 10 second beat note on WWV at 10 MHz. (I *hope* I got the
decimal point right that time).
Fire up your radio and start listening to the various frequencies. You want a
time when it’s crystal clear with absolutely no
I'm not ready to delve into temperature measurement. But I thought
conventional wisdom is that most crystals are AT cut and an attempt at zero
average coefficient is made, causing a nonlinear characteristic. But perhaps
over a limited range it's linear. The problem of course is calibration.
Yes Nigel, it's a waste of time but so are computer games and going to
Disneyland and such. We do it because we get pleasure, and nobody can
criticize that.
I am a bit confused over your mention of Trimble units. I'm not familiar with
them or what they are supposed to do. I better do some
Hi
On Mar 2, 2014, at 10:58 AM, Bob Albert bob91...@yahoo.com wrote:
I'm not ready to delve into temperature measurement. But I thought
conventional wisdom is that most crystals are AT cut and an attempt at zero
average coefficient is made, causing a nonlinear characteristic. But perhaps
Hi
Trimble is one of many companies in the GPSDO business. A GPSDO is an
oscillator that is locked up to the GPS signal. In many cases the oscillator is
a pretty good OCXO. Trimble made a lot of these for the cell tower people. They
now show up pretty regularly on the surplus market.
A GPSDO
FSCM 38243 is the manufacturer information. FSCM is the Federal
Supply Code for Manufacturers, which appears to be a subset of CAGE
(Commercial and Government Entity) codes maintained by the Defense
Logistics Agency. FSCM 38243 appears to be PG Electronics Ltd,
currently of Schomberg Ontario
BA I am a bit confused over your mention of Trimble units. I'm not
familiar with them or what they are supposed to do.
BA I better do some homework.
The best thing said so far ...
Scan the archives and Google for GPSDO, do some research and reading
Then the archives for Trimble then for
On 3/2/14 8:32 AM, Glen Hoag wrote:
FSCM 38243 is the manufacturer information. FSCM is the Federal Supply
Code for Manufacturers, which appears to be a subset of CAGE (Commercial
and Government Entity) codes maintained by the Defense Logistics
Agency. FSCM 38243 appears to be PG Electronics
li...@rtty.us said:
A number of them have sold recently on eBay for about $130.
Don't forget the antenna and power supply.
--
These are my opinions. I hate spam.
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In a message dated 02/03/2014 16:06:49 GMT Standard Time,
bob91...@yahoo.com writes:
Yes Nigel, it's a waste of time but so are computer games and going to
Disneyland and such. We do it because we get pleasure, and nobody can
criticize that.
-
Hi Bob,
I'm not
bob91...@yahoo.com said:
But I thought conventional wisdom is that most crystals are AT cut and an
attempt at zero average coefficient is made, causing a nonlinear
characteristic. But perhaps over a limited range it's linear. The problem
of course is calibration.
Most crystals are low
Hi
Depending on which auction you find and what they include you may indeed have
some other bits and pieces to dig up as well. The prices run in cycles, so you
will always pay a bit more if you “want it right now” than if you are willing
to sit back and shop for a few months.
Bob
On Mar 2,
Hi
These days, you can get some *very* low cost crystals. They sell by the pound
rather than by the piece. The tolerance as delivered may be 0.1% for
temperature plus calibration. Aging is likely to be “who knows”. The
temperature characteristic could be a third order curve. More likely it’s a
- Original Message -
From: Hal Murray hmur...@megapathdsl.net
To: Bob Albert bob91...@yahoo.com; Discussion of precise time and
frequency measurement time-nuts@febo.com
Cc: hmur...@megapathdsl.net
Sent: Sunday, March 02, 2014 2:45 AM
Subject: Re: [time-nuts] Another atomic clock
It looks like the input hits a 2 way splitter that drives each of four
ports. Most of these have at best a 3 dB loss, more like 4.5 dB. Then it
each of those gets split again to drive two ports. Then another split to
each port. So lets say at best it is 3 + 3 +3 = 9 dB. But being broadband, I
Nigel,
Thank you for your comments. I see the situation a bit more clearly now, and
will do some searches on Trimble and GPSDO and so on. Right now I am
interested in seeing what my options are, and deciding which way to go.
Yes this can become an obsession but I keep reminding myself that
Hi
If you look at the wiring to the input connector and the output connectors,
that’s not the way you wire VHF or UHF gear. The same is true for the “ground
through case” on those connectors.
Bob
On Mar 2, 2014, at 12:54 PM, Tom Miller tmiller11...@verizon.net wrote:
It looks like the
HI
If that is what you currently have for references, then you probably need a
“lab standard” to drive things. Having one reference for all the gear makes
things *much* easier. You don’t have to mess with a lot of “which one’s right
today” sort of decisions.
That would make the GPSDO pretty
Junk crystals are good thermometers. Ballpark is 1 ppm/degree-C
So does this mean I can epoxy a sandstone power resister to a junk
crystal and keep the frequency exactly perfect by varying the power in
the resister?
--
Chris Albertson
Redondo Beach, California
Hi
As long as your resistor keeps the temperature to within a micro degree it will
do pretty well.
Bob
On Mar 2, 2014, at 2:09 PM, Chris Albertson albertson.ch...@gmail.com wrote:
Junk crystals are good thermometers. Ballpark is 1 ppm/degree-C
So does this mean I can epoxy a sandstone
On 3/2/14 11:09 AM, Chris Albertson wrote:
Junk crystals are good thermometers. Ballpark is 1 ppm/degree-C
So does this mean I can epoxy a sandstone power resister to a junk
crystal and keep the frequency exactly perfect by varying the power in
the resister?
Yes.. but you have to hold
On 3/2/14 12:21 PM, Bob Camp wrote:
Hi
As long as your resistor keeps the temperature to within a micro degree it will
do pretty well.
Oh, you were looking for 1E-12.. I was thinking 1E-9 would be good enough.
The other issue is that the phase noise might be pretty bad with a cheap
Hi
The gotcha is that there are second order temperature effects. If you are going
to run the crystal very far off turn, you need to keep it more stable than you
might think.
Bob
On Mar 2, 2014, at 3:40 PM, Jim Lux jim...@earthlink.net wrote:
On 3/2/14 12:21 PM, Bob Camp wrote:
Hi
As
On 02/03/14 21:45, Bob Camp wrote:
Hi
The gotcha is that there are second order temperature effects. If you are going
to run the crystal very far off turn, you need to keep it more stable than you
might think.
hysteresis, memory effect, restart of frequency drift
Yeah, it puts a limit on
On 3/2/14 1:00 PM, Magnus Danielson wrote:
On 02/03/14 21:45, Bob Camp wrote:
Hi
The gotcha is that there are second order temperature effects. If you
are going to run the crystal very far off turn, you need to keep it
more stable than you might think.
hysteresis, memory effect, restart of
Thanks All for the information ! I'll try to contact PG Electronics
for the specifications.
For now, I have no access to precision instruments to measure certain
parameters of that module. The whole idea is to have couple of extra
sine outputs from my Trimble T-bolt. I am thinking to hook
This is actually pretty interesting to me. The questions of how to choose
an RTOS and how to handle power management seem to be relevant engineering
topics when discussing the 5370 processor boards. It's not an academic
question in the professional world, where certain instruments I won't name
HI
On Mar 2, 2014, at 4:00 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote:
On 02/03/14 21:45, Bob Camp wrote:
Hi
The gotcha is that there are second order temperature effects. If you are
going to run the crystal very far off turn, you need to keep it more stable
than you might
We should have a Broadband Time-nuts for this sort of thing. This
topic is also of interest to me, and I have good pointers to give about
how to implement it with minimum effort, but as the owner asked it to
stop before I could reply i´m keeping quiet :)
Daniel
Em 02/03/2014 19:09, John
Hi Bob,
On 02/03/14 23:16, Bob Camp wrote:
HI
On Mar 2, 2014, at 4:00 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote:
On 02/03/14 21:45, Bob Camp wrote:
Hi
The gotcha is that there are second order temperature effects. If you are going
to run the crystal very far off turn, you
I have spent another evening playing around with the 5370 and the
conclusion is pretty ironclad now:
Running a 5370 with ext-ref locked to input frequencies is simply
a bad idea and should not be done.
Running it on the internal OCXO works fine.
Running it on another frequency *not* locked to
John
I would be interested. I just re-signed up to yahoo. But frankly that was a
bit flaky. Something about you have to be invited in or checked out or
something. Never did get a response back.
Regards
Paul
WB8TSL
On Sun, Mar 2, 2014 at 5:18 PM, Daniel Mendes dmend...@gmail.com wrote:
We
On Mar 2, 2014, at 5:29 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote:
Hi Bob,
On 02/03/14 23:16, Bob Camp wrote:
HI
On Mar 2, 2014, at 4:00 PM, Magnus Danielson mag...@rubidium.dyndns.org
wrote:
On 02/03/14 21:45, Bob Camp wrote:
Hi
The gotcha is that there are second
tmiller11...@verizon.net said:
Is that 3 MHz OCXO one from Ridge? If so, I opened one up and was surprised
to find it did not have any foam insulation.
RDR Electronics
There were 2 per board, from some old telco/cell gear.
http://w9fz.com/ham/s3mhz2.jpg
http://w9fz.com/ham/3mhzocxo.txt
Hi
Do you have any idea how “clean” your 200 MHz signal is? The manual suggests
getting it to -65 dbc for subs using a spectrum analyzer. That’s pretty far
down. I seem to recall the adjustment process being a bit tedious (lots of back
and forth).
Bob
On Mar 2, 2014, at 5:29 PM,
As Jim mentions in another post, you can run on the fundamental and the third
(or 5th or 7th) and get a thermometer out of the delta between the two modes.
The gotcha is that a change in load impedance will shift the frequencies
unequally. That will give you an apparent temperature change.
I
This is actually pretty interesting to me. The questions of how to choose
an RTOS and how to handle power management seem to be relevant engineering
topics when discussing the 5370 processor boards. It's not an academic
question in the professional world, where certain instruments I won't
svn64 alive and well
Using sirfdemo pc software coupled with sirf iv gps receiver I picked up
the first signal from svn64 (now
assigned prn30).
The sat was launched from cape canavral (airforce station) florida last
thursday evening 2-20-14 about 17:55pdt.
The gps control people seem to
Hi
I believe the paper was by Stan Shadowski. I’m *certain* I’ve mis-spelled his
last name, which is indeed a very poor move on my part. I would not be
surprised if there are several co-authors.
I don’t have the UFC indexes here at home so I have no quick way to look it up.
Bob
On Mar 2,
Thanks All for the information ! I'll try to contact PG
Electronics for the specifications.
For now, I have no access to precision instruments to measure
certain parameters of that module. The whole idea is to have couple
of extra sine outputs from my Trimble T-bolt.
Just put 10MHz in
Hi
The countdown clock on the Oscars looks like it’s about 11 seconds off here in
PA. Time is part of a *lot* of things ….
Bob
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On Sun, 2 Mar 2014 20:25:20 -0500
Bob Camp li...@rtty.us wrote:
Hi
The countdown clock on the Oscars looks like it’s about 11 seconds
off here in PA. Time is part of a *lot* of things ….
Bob
One suspects that is for the censors to react and hit the button.
In message e7a494f6-78f1-4568-8bd3-d94a32deb...@rtty.us, Bob Camp writes:
Do you have any idea how 'clean' your 200 MHz signal is? The manual
suggests getting it to -65 dbc for subs using a spectrum analyzer. That's
pretty far down. I seem to recall the adjustment process being a bit tedious
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