On 3 Oct 2008 at 13:41, Steve Rooke wrote:
Call me crazy but I wonder if my accurate relative period of time
could be derived from the 230VAC 50Hz mains supply over here. Now,
before you yell at me, consider this, I have a couple of mains driven
clocks in the house and only seem to need to
Sounds like a isolator, a passive ferrite device.
Stan, W1LECape Cod
[EMAIL PROTECTED] wrote:
I don't know a whole bunch about microwave gear, so I need a little help. I
came across a small box in a pile this evening and I don't have a clue what
it is.
It's a T construct, with SMAs
Ferrite circulator.
Black insert is ferrite
If one of the three ports is terminated, it¹s hooked up as an isolator.
Jim
On 10/3/08 1:43 AM, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote:
I don't know a whole bunch about microwave gear, so I need a little help. I
came across a small box in a
My Austron 2100T outputs have significant noise on the peaks of pulses
and square wave output,Is this normal or is this a fault I need to
correct other than that it works quite nicely and I am usually locked
to Nantucket MA or Seneca NY if Nantucket is out of service
Thanks Scott N1JIN
You need one other piece of gear then. A dIstribution amplifier if
you do not already have one - they come up pretty frequently on ebay
and there is a thread on building the NIST reference design ongoing
the thread title is homebrew 13 dBm distribution amplifier based on
NIST design 5 to 100 MHz
Hi Chris,
2008/10/3 Chris Cheney [EMAIL PROTECTED]:
A bit of Googling finds:
Frequency: a variation not exceeding 1 per cent above or below the
declared frequency;
(http://www.statutelaw.gov.uk/content.aspx?LegType=All+Legislationtitle=e
Scott. Yes, I'm working on acquiring a DA. I'm also considering homebrewing
one. I've been watching the thread on the NIST design.
Jeff
Jeffrey K. Okamitsu, PhD, MBA
+1-609-638-5402
--- On Fri, 10/3/08, Scott McGrath [EMAIL PROTECTED] wrote:
From: Scott McGrath [EMAIL PROTECTED]
Subject:
Tom,
2008/10/3 Tom Van Baak [EMAIL PROTECTED]:
Ah, if you are a time-nut of course you will bite the bullet and
get a GPSDO. But you should also not give up on the PC idea.
If it works it will be a great gift to many people (OK, maybe not
the pico- and nanosecond crowd, but to regular
Tom,
Sorry to post in response to my previous post but perhaps this system
could work if the input signal did have a quite a slow rise time. I
was thinking more of coupling the output of the proposed 1KHz divider
through quite a small amount of low-pass filtration. If the 1KHz was
passed through
On the DA you will want to ensure all your output cables are of
identical length as this will ensure that all signals are in phase at
the timebase input(s). It's a small thing really a fraction of a
picosecond but it's there and easily compensated for.
If you are after picoseconds, you
A better way to cut coax to the right delay lengths is to use a network
analyzer.
From my experience, basing your calculations on the assumed value of the
dielectric constant of the cable can lead to significant errors based on the
actual quality of the cable.
Even so called high quality
On the DA you will want to ensure all your output cables are of
identical length as this will ensure that all signals are in phase at
the timebase input(s). It's a small thing really a fraction of a
picosecond but it's there and easily compensated for.
When does the phase of the timebase
This would produce a lot of data and be quite intensive in processor
time. Sampling the input waveform is easy as it's done in hardware on
There's no need to time-stamp each sample (and I'm not sure
this is even possible with sound card API's). What I meant is to
time-stamp each sound card
Or use a TDR like the Tektronix 7S12.
RG400 (solid PTFE dielectrice IIRC) in my experience typically comes out at
about 8.6 per nS which is slightly at odds with the published propogation
speed of .69 which would suggest 8.28. The 5nS cables I made up not long
back are almost exactly 43 long.
Electric clock time: NGET will endeavour (in so far as it is able) to
control electric clock time to within plus or minus 10 seconds
(http://www.nationalgrid.com/NR/rdonlyres/4894C7AA-DCD2-4835-9986-
57338C31C86A/9922/BC3_i3r18.pdf - section BC3.4.3)
For some reason I could not get this
I have an HP5371A with a problem. It fails the Input Amplifier test.
The error message says Bad Comparator: Result A: stuck low.
If you do a auto trigger level set, channel A gives flakey readings.
When measuring the internal timebase signal (patching the back
panel BNC to the input pods)
Tom Van Baak wrote:
On the DA you will want to ensure all your output cables are of
identical length as this will ensure that all signals are in phase at
the timebase input(s). It's a small thing really a fraction of a
picosecond but it's there and easily compensated for.
When does
WB6BNQ wrote:
Tom Van Baak wrote:
On the DA you will want to ensure all your output cables are of
identical length as this will ensure that all signals are in phase at
the timebase input(s). It's a small thing really a fraction of a
picosecond but it's there and easily compensated for.
Steve
So what you end up doing is using the sound card like a high
resolution vernier between NTP timekeeping on the inside and
your UUT on the outside. I bet you a Thunderbolt that you can
measure to 1 ppm within ten seconds.
Lets see, phase shift of 1ppm in 10 seconds at a sampling
Steve Rooke wrote:
Tom,
Sorry to post in response to my previous post but perhaps this system
could work if the input signal did have a quite a slow rise time. I
was thinking more of coupling the output of the proposed 1KHz divider
through quite a small amount of low-pass filtration. If the
Tom,
You are correct - I let my college years buidling coincidence
detectors in college for the GRO-COMPTEL as well as television
broadcast engineering. in both applications it mattered whether all
instruments used were in precisely defined phase relationships and I
have been letting this
When does the phase of the timebase input mean anything?
Most test equipment is happy to have a stable external frequency
input; the phase is immaterial, no? Can someone give me an example
when relative phase among various random pieces of test
equipment is
important?
/tvb
Hi
Tom Van Baak wrote:
On the DA you will want to ensure all your output cables are of
identical length as this will ensure that all signals are in phase at
the timebase input(s). It's a small thing really a fraction of a
picosecond but it's there and easily compensated for.
When does
I've been fiddling around with an old Cisco router here at the house
to brush up. We have an IPv6 project going at work, and our WAN
provider provides no native transit, so I'm looking at doing some
tunneling. Anyhow... I discovered IOS 12.1 and above have native NTP
capability. I
In this case, cable quality is critical and controlling cable characteristics
(as a function of temperature, humidity, etc.) is also critical.
Jeff
Jeffrey K. Okamitsu, PhD, MBA
+1-609-638-5402
--- On Fri, 10/3/08, Bruce Griffiths [EMAIL PROTECTED] wrote:
From: Bruce Griffiths [EMAIL
For an interferometric application, isn't it sufficient to maintain constant
phase difference?
Jeff
Jeffrey K. Okamitsu, PhD, MBA
+1-609-638-5402
--- On Fri, 10/3/08, Lux, James P [EMAIL PROTECTED] wrote:
From: Lux, James P [EMAIL PROTECTED]
Subject: Re: [time-nuts] AC Connector On HP 5061B
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Jeffrey Okamitsu
Sent: Friday, October 03, 2008 2:46 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] AC Connector On HP 5061B
For an interferometric application,
The cable length issue was a pain for me because I built my GPS box in stages,
leaving the dist amp for last. In the end I found a nice used commercial unit,
but it didn't fit in the planned location (the unit I was going to build would
have had outputs near the center of the box), so I have 3
Lux, James P wrote:
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Jeffrey Okamitsu
Sent: Friday, October 03, 2008 2:46 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] AC Connector On HP 5061B
For an
On Fri, Oct 03, 2008 at 06:46:17PM -0400, [EMAIL PROTECTED] wrote:
From: Robert Vassar [EMAIL PROTECTED]
Subject: [time-nuts] GPS, NTP, and Cisco routers...
I've been fiddling around with an old Cisco router here at the house
to brush up. We have an IPv6 project going at work, and our WAN
Depending on frequency, achieving the necessary phase matching surely must be
achievable electrically or, at microwave frequencies, via a variable length
waveguide?
I can't imagine that for a precision application one would rely on a coaxial
cable maintaining it's length and its other
I had the same problem with that link to FREQUENCY CONTROL PROCESS but
then realized that the actual link carried on the next line below, you
should have some success with the link here, it may still be to long for the
page width but just copy and paste into your address bar,
if you haven't
Bruce Griffiths [EMAIL PROTECTED] wrote:
Mike
They actually use an augmented form of GPS common view for which
the GPS PPS signal and its timing variations are largely common to
both locations and thus largely cancel when comparing the
frequencies at the customer
Thanks Clint, it worked this time.
2008/10/4 Clint Jeffrey - VK3CSJ [EMAIL PROTECTED]:
I had the same problem with that link to FREQUENCY CONTROL PROCESS but
then realized that the actual link carried on the next line below, you
should have some success with the link here, it may still be to
Bruce Griffiths [EMAIL PROTECTED] wrote:
Tom
Another example of a case where the electrical length of a cable
can be important is in precision frequency distribution systems.
Trimming the cable to the right length (one way propagation delay
equal to an odd multiple of half
Hi Mike,
Rick's CNSC02-O1 implementation has been discussed here
a number of times over the years (google the archives). It uses
a programmable digital delay line to compensate for the receiver
reported quantization error on each pending 1 pps.
Here's a quick plot of an M12+ receiver without
Mike Monett wrote:
For more detail see:
http://tf.nist.gov/timefreq/service/fms.htm
Thanks very much for the link. It is curious they don't seem to
spend much effort on correcting the user's frequency errors. They
just want to report how much they are off.
Why is
I suspect another reason is that even if it were adjusted, a user's
individual standard would still deviate from the NIST average standard, and
the drift would have to be accounted for anyhow, so what's the point of
attempting to mess with it and take the risk of loosing the data accumulated
so
Tom Van Baak [EMAIL PROTECTED] wrote:
Hi Mike,
Hi Tom,
I want to thank you for the very nice reply you gave to my email a
while ago. Unfortunately, I am still learning about precision
frequency references, and I don't have enough knowledge yet to give
you an intelligent
Hi All,
I have a NTS-100 GPS model. I am going to be putting it into use @ my
employers where I have a T1 Rooftop access backup power. It has the
lovely downconverter required sticker on the back of it. It does NOT
like my trimble bullet antenna. Can someone let me know how I can get
Mike Monett wrote:
Bruce Griffiths [EMAIL PROTECTED] wrote:
Tom
Another example of a case where the electrical length of a cable
can be important is in precision frequency distribution systems.
Trimming the cable to the right length (one way propagation delay
equal to
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