[GPS_Standard] Re: GPS_Standard Digest, Vol 9, Issue 1

[Bert, VE2ZAZ]

Hello Arie,

An 11-digit counter could display a frequency with a resolution of up to 11
digits. The counter determines how many accurate digits it can display based
on the sampling time selected. This could ultimately correspond to an
accuracy of 3x10^-11 at 3GHz. This obviously assumes that the counter
timebase is accurate enough! The built-in TCXO cannot provide that kind of
accuracy, but an external one can. This is why they provide up to 11 digits.
To obtain that many digits, the counter actually measures the period (time
interval), not the frequency. It then converts the measurement to a
frequency for display.

The picture in the article is misleading in that sense. I don't use the
counter to check my GPS-Derived Frequency Standard accuracy. It is merely
there to provide a better looking cover page!... You will have guessed that,
for that picture, both the counter input and external reference input are
connected to the GPS standard in order for the counter to read 10MHz
exactly.

Best Regards,

Bert, VE2ZAZ



----- Original Message -----
From: "Arie Dogterom" <pa0ez at amsat.org>
To: <gps_standard at mailman.qth.net>
Sent: Monday, July 09, 2007 4:19 AM
Subject: [GPS_Standard] Re: GPS_Standard Digest, Vol 9, Issue 1


Dr Bert,
Interesting what you say about that HP counter.
You are giving it an "accuracy" figure of 10^-11. How do they do that?. One
does not need to lock to gps. Or has it an 11 digit resolution?
73
Arie

----- Original Message -----
From: <gps_standard-request at mailman.qth.net>
To: <gps_standard at mailman.qth.net>
Sent: Monday, July 09, 2007 10:01 AM
Subject: GPS_Standard Digest, Vol 9, Issue 1


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> Today's Topics:
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>   1. Construction Question(s) (k7hbg at dslextreme.com)
>   2. Re: Construction Question(s) (Bert, VE2ZAZ)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sun, 8 Jul 2007 10:50:55 -0700 (PDT)
> From: k7hbg at dslextreme.com
> Subject: [GPS_Standard] Construction Question(s)
> To: gps_standard at mailman.qth.net
> Message-ID:
> <30570a10c8ea325aaa5b4f0a.20070708105055.x7uot at www.dslextreme.com>
> Content-Type: text/plain;charset=iso-8859-1
>
> Hi Bert;
> My construction efforts continue. I have a couple of questions for you.
> 1) What kind of enclosure did you use? At least, furnish the dimensions if
> you please.
> 2) What is that nifty HP. frequency counter in the article picture? It's
> just my size, non racked.
>
> Best regards, Bob K7HBG
>
>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Sun, 8 Jul 2007 20:11:20 -0400
> From: "Bert, VE2ZAZ" <ve2zaz at sympatico.ca>
> Subject: Re: [GPS_Standard] Construction Question(s)
> To: <k7hbg at dslextreme.com>, <gps_standard at mailman.qth.net>
> Message-ID: <068EDDDA09B344348BE8C8158D6F809C at zaub2>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hi Bob,
>
> The enclosure I used is a recycled 12-port data switchbox. It is 10 in.
> wide
> x 3 in. high x 7 in. deep. Unfortunately, it is made of steel  :-( Quite a
> pain to re-work! I will never use a steel box again...I put new aluminum
> front and rear plates.
>
> The counter I use is the HP 5386A. It is rather expensive on Ebay, but I
> got
> mine for 20$, a steal! I like it a lot. It provides up to 11 digits of
> accuracy, is good up to 3GHz and has GPIB interface. HP 5384/5/6 series is
> a
> good line of counters.
>
> Cheers,
>
> Bert, VE2ZAZ
>
> ----- Original Message -----
> From: <k7hbg at dslextreme.com>
> To: <gps_standard at mailman.qth.net>
> Sent: Sunday, July 08, 2007 1:50 PM
> Subject: [GPS_Standard] Construction Question(s)
>
>
> Hi Bert;
> My construction efforts continue. I have a couple of questions for you.
> 1) What kind of enclosure did you use? At least, furnish the dimensions if
> you please.
> 2) What is that nifty HP. frequency counter in the article picture? It's
> just my size, non racked.
>
> Best regards, Bob K7HBG
>
>
>
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> End of GPS_Standard Digest, Vol 9, Issue 1
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