[time-nuts] UK standard frequencies - where?

David J Taylor david-taylor at blueyonder.co.uk
Wed Oct 12 12:54:49 UTC 2011

> David,
> I'm 70km north of London and have used the French 162kHz high stability 
> signal as well as RWM (Moscow) on 4.996, 9.996 and 14.996MHz for 
> frequency measurement and calibration before I got my Thunderbolt. RWM 
> is particularly good because part of the schedule involves sending 
> continuous carrier, which I used with SpectrumLab to calibrate 
> transceivers - you simply use SSB, offset the transceiver by 1kHz to get 
> an audio tone and measure the error using the waterfall on SPLab.
> Regards,
> David, Milton Keynes, UK  (G4IRQ)


This was an excellent suggestion!  Briefly, I have an audio oscillator 
with a built-in counter where I could generate 1 KHz +/- 1Hz, and I 
compared this against a computer generated 1 KHz tone using my 'scope.


I then installed Spectrum Lab (I had a very old version but wasn't using 
it), and found that the 1 KHz displayed most close to 1 KHz when the 12000 
or 48000 sampling frequencies were selected.  Then found that the RX was 
60 Hz low at 14.996 MHz and about 400 Hz low on the local BBC FM 
transmitters (88.9 - 94.3 MHz), which was a consistent error.  LO on the 
R8500 tweaked against the 14.996 MHz, and the 9.996 MHz transmission was 
then spot-on.

As a final check, the Edinburgh Tower ATC then showed just 6 Hz high, so a 
most satisfactory result.  I can now tweak my FUNcube Dongle with greater 

David GM8ARV
SatSignal software - quality software written to your requirements
Web:  http://www.satsignal.eu
Email:  david-taylor at blueyonder.co.uk 

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