[Elecraft] VFO calibration

Sun Dec 29 18:50:05 2002

For those that need the 10 to the minus 12th accuracy and have a few extra
$$$ to spend, the HP Z3801A GPS Clock units work great. I use a similar unit
as the timebase to my frequency counters. Here is one of many being
advertised on ebay.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=25399&item=3101606326

-rob N7QT

----- Original Message -----
From: "Roy" <[email protected]>
To: "Don Brown" <[email protected]>; "Helmut Usbeck" <[email protected]>;
<[email protected]>
Sent: Sunday, December 29, 2002 1:46 PM
Subject: Re: [Elecraft] VFO calibration

> At 11:47 AM 12/29/02 -0600, Don Brown wrote:
> >Hi
> >
> >Actually as some who worked in several calibration labs (Tektronix, GE
and
> >several independents)
> >That is exactly what we do. The frequency standard in most cal labs is a
> >special receiver that is phase locked to the WWV carrier. The calibration
> >certificates state that the instrument is traceable to NBS. WWV is part
of
> >the NBS so it is the standard all other standards are compared to and
even
> >if a lab is using a rubidium or cesium standard they are calibrated
against
> >the ones at NBS. The WWV carrier is phase locked to their internal
standard
> >and the several standards are compared to each other to maintain the
> >reference.
> >
> >Don Brown
> >KD5NDB
> >
> >----- O
> >
> > >
> > > -Someone mentioned that all counters are calibrated against WWV.  I
don't
> > > know where that urban (or rural) legend came from.  If you think that
> > > down at H-P techs are zeroing in counters with an old Grundig tuned to
10
> > > Mc. you're off.  I had mine sent to a lab where it was compared to a
> >rubicon
> > > standard.  Which of course is what WWV uses as it's standard.
>
>
>   At the NIST lab I work
>    at, we have not used the WWV method for quite a few years now. But it
> worked fine when we did. Now we sync our cesium to a signal from GPS.
Then
> we sync our rubidiums using the cesium. The GPS is now considered an
> "absolute standard" . Time marches on!  Couldn't resist that one. 73 Roy
AB7CE
>
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