On Tue, Nov 30, 2010 at 5:33 AM, shali...@gmail.com wrote:
Just find any HP 10811, by itself or inside an instrument (you can often buy
a whole instrument with an internal 10811 cheaper than you can buy the 10811
by itself).
What HP instruments would have the HP 10811 inside?
--
Subject: Re: [time-nuts] If there a FAQ
On Tue, Nov 30, 2010 at 5:33 AM, shali...@gmail.com wrote:
Just find any HP 10811, by itself or inside an instrument (you can often
buy a whole instrument with an internal 10811 cheaper than you can buy the
10811 by itself).
What HP instruments would
-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
Behalf Of Chris Albertson
Sent: Tuesday, November 30, 2010 1:29 PM
To: shali...@gmail.com; Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] If there a FAQ
On Tue, Nov 30, 2010 at 5:33 AM, shali
On Sun, 2010-11-28 at 21:41 -0800, Chris Albertson wrote:
WWV at 10MHz is not bad at all. My current system is a cheap
$0.75 10Mhz crystal tuned with a screwdriver on a veritable trimmer
capacitor. I know I can zero-beat it by ear and get within a couple Hz
out of 10MHz. That is better
It all depends on what your goal is. A couple of Hertz at 10 MHz will
keep you well within any of the HF ham bands.
The following addresses beyond the 'Gotta stay in the band' issue.
The problem with the Zero-beat-WWB-at-10-MHz technique is that WWB is
changing frequency. Not at the
albertson.ch...@gmail.com said:
What low cost GPSes should I look at?
These days, most low cost GPS units are USB, but those don't have a PPS
signal.
You may be able to find the PPS signal on the module in there if you take it
apart.
These are the only low cost ones I know of with PPS.
-
From: Hal Murray hmur...@megapathdsl.net
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Monday, November 29, 2010 8:31 AM
Subject: Re: [time-nuts] If there a FAQ
I know I can zero-beat it by ear and get within a couple Hz out of
10MHz.
That is better
and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] If there a FAQ
I know I can zero-beat it by ear and get within a couple Hz out of
10MHz.
That is better then 1E-6 simply by hand, ear and screwdriver. No
computer.
How do you get down to a couple Hz? I thought most (young
You don't need hearing ability for low pitches. As the beat frequency
gets lows it
it sounds like the volume is being pulsed. Like something is playing
with the volume
knob once per second.
It is the same say you tune a musical instrument.You listen for
volume modulation.
The two pitches
I'm new to this list. Before I ask a lot of questions maybe someone
can point me at some reading material.
I've decided I want a decent frequency reference for normal ham radio
stuff like calibrating test equipment, testing oscillators for
stability and so on.
I figure at first I'll start with
WWV is not a very good option. The signal fades a lot and has HF noise
issues unless you have a really good location within ground wave. Carrier
tracking is likely hard, which means you have to deal with the 1 PPS pips.
I've used a digital averaging scope, triggered by the 1 PPS from my local
WWV at 10MHz is not bad at all. My current system is a cheap
$0.75 10Mhz crystal tuned with a screwdriver on a veritable trimmer
capacitor. I know I can zero-beat it by ear and get within a couple Hz
out of 10MHz. That is better then 1E-6 simply by hand, ear and screwdriver.
No computer.
The
Chris Albertson wrote:
I'm new to this list. Before I ask a lot of questions maybe someone
can point me at some reading material.
There's a great presentation from John Vig on the web..
The Ap note from HP on time and frequency is also good.
First question is a source of parts.
and frequency measurement
Subject: Re: [time-nuts] If there a FAQ
WWV at 10MHz is not bad at all. My current system is a cheap
$0.75 10Mhz crystal tuned with a screwdriver on a veritable trimmer
capacitor. I know I can zero-beat it by ear and get within a couple Hz
out of 10MHz. That is better then 1E
There's a great presentation from John Vig on the web.. The Ap note from HP
on time and frequency is also good.
Another very good presentation:
Timing for VLBI, Tom Clark and Rick Hambly:
http://gpstime.com/files/tow-time2009.pdf
Another really good read is:
Time Too Good to Be True,
Hi Folks,
Well my 5370B purchased off ebay arrived from the US in perfect
condition. It passed all the operator checks (all well within spec)
and the only issue being that the internal 10811 oscillator was
running a tad slow. A quarter of a turn with the screwdriver fixed
that.
Having played
Congratulations! It's a wonderful instrument, isn't it?
I can answer a few of your questions.
Set/clear ref - after power-on or a reset, the ref value is (should be)
zero.
When set-ref is pressed, the current time interval average value is
stored. This remains set until a power-off/reset or you
wje wrote:
Freq vs time interval - simplistic answer: when you're using
time-gating, you're looking at more samples than in averaged one-period
mode. For 10Mhz, a gate of 0.1 secs is 1 million periods. In period
mode, you're averaging a maximum of 100,000 periods. Accuracy is
Why, you use your 8082A! I got one for a steal a couple of years ago on
EBay.
However, all you really need is a fast rise-time pulse generator that
has external triggering and a variable trigger delay, and can generate
a +1/-1 volt swing. The frequency the tests use aren't that
wje wrote:
Why, you use your 8082A! I got one for a steal a couple of years ago on
EBay.
I've been looking for a year now, and I haven't found any 8082A's below $400.
Well, there were a couple, but they were a real mess.
5370A's, which are equivalent to the 5370B in all respects have
Subject: Re: [time-nuts] 5370B arrived - any FAQ
Why, you use your 8082A! I got one for a steal a couple of years ago on
EBay.
However, all you really need is a fast rise-time pulse generator that
has external triggering and a variable trigger delay, and can generate
a +1/-1 volt swing
, June 19, 2008 9:01 AM
Subject: Re: [time-nuts] 5370B arrived - any FAQ
Why, you use your 8082A! I got one for a steal a couple of years ago on
EBay.
However, all you really need is a fast rise-time pulse generator that
has external triggering and a variable trigger delay, and can
As to the frequency measurement based on 1 period
timing; I think you'll find that what's actually measured
is the period, whose reciprocal is displayed as frequency.
This means that the channel A trigger point set the start
the channel B trigger point set the stop of the period
measurement. A
Because you need something that has a finely variable delay in the
range of 2 to 5ns, a pulse width adjustable from 5 to 50ns, and a minimum
transition time of less than 1ns. And, it has to be able to drive 50 ohms
to +/-1V.
The 8015A's shortest delay is 20ns, and its minimum pulse width is
I would suggest you go through the detailed alignment procedures even
though the unit passes the operational checks. These units almost always
have drifted out of alignment in the analog front-end unless you were
lucky enough to get a freshly-calibrated one. You can usually
significantly
Well the operational check jitter reports at 11 psec. I'm very happy
with that and so I'm not going to fiddle with anything for the moment!
Jim
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