[time-nuts] If there a FAQ

[Bill Hawkins]

Chris,

If you are familiar with vacuum tube stuff, I have a basket-case
Beckman 905 WWV receiver that you can have for shipping. The radio
was discarded because the 6AQ5 coupling capacitor got leaky and
caused smoke to be released from the power transformer, which is
otherwise OK. It was then sprayed with a fire extinguisher, which
ruined the speaker but didn't get past the front panel.

The 905 is a five channel crystal controlled dual conversion
receiver. Information is available on the web. It's in a basket
because I never got around to repairing it, after taking it apart.

Actually, if you have a good communication receiver, you have all
you need to set a 10 MHz crystal to 1E-8, if the adjustment has any
stability. That's a ten second beat rate. Then you need to filter
out the temperature variations, or fool around with NPO caps to
compensate for temperature variations.

Well maybe 1E-7, which is normal for WWV over the Rockies (sky-
wave).

Bill Hawkins

 

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Chris Albertson
Sent: Sunday, November 28, 2010 11:42 PM
To: jfor at quik.com; Discussion of precise time 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-6 simply by hand, ear and screwdriver.
No computer.

The trouble with a 60Khz signal is that a two cycle error gives
a 1 in 30K error,

I'm just looking to use it as a frequency standard, not caring at all about
the
data they transmit

I figure my first upgrade is to replace the crystal with a temperature
compensated oscilator chip.   Now to go find one.

-- 
=====
Chris Albertson
Redondo Beach, California