[Elecraft] SW broadcast to calibrate against.
Dave G4AON
elecraft at astromag.co.uk
Sun Jan 13 03:19:23 EST 2008
Calibrating one 1 ppm TCXO against another 1 ppm TCXO calibrator (for
those with the optional extra K3 KTCXO3-1) would not be a good idea. In
any event the calibrator is going to drift with time and need
calibrating itself every year or so.
G4JNT published a 60 KHz off air frequency standard in the RSGB
publication "RadCom" in April 1994 (Mk 1 version) and March 1996 (Mk 2
version). I have used his Mk2 version for some years and it works well,
admittedly it's only good to a short term stability of 1 part in 10^8
but that's still 50 to 100 times more stable than the TCXO in a K3 you
are trying to calibrate. Long term the stability matches that of the
national standard being broadcast. Cost of building is minimal, even
allowing for the box, switches, paint, etc. I would expect a lot of
change from $80 or £40.
On eBay GPS and rubidium units appear from time to time, I bought a GPS
unit part kit, built by the guy who later sold another one:
http://cgi.ebay.co.uk/GPS-10Mhz-FREQUENCY-STANDARD-COMPUTER_W0QQitemZ120166344327QQihZ002QQcategoryZ25399QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
He seems to like making GPS standards, so maybe worth dropping him an
e-mail?
73 Dave, G4AON
K3/100 #80
-------------------
Rather than a BC station, how about a fairly accurate 10Mhz frequency
standard like
http://www.aade.com/freqstd/freqstd.html
73 to all
Trevor G0KTN
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