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)
David,
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.
http://www.satsignal.eu/software/audio.html#SweepGen
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
confidence!
73,
David GM8ARV
--
SatSignal software - quality software written to your requirements
Web: http://www.satsignal.eu
Email: [email protected]
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