[time-nuts] UK standard frequencies - where?
d.bobbett at tiscali.co.uk
Wed Oct 12 09:00:07 UTC 2011
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.
The technique is prone to sound card errors but these can be quantified
and there are various tricks which can be used to minimise error,
probably better discussed by e-mail.
I'd be (pleasantly) surprised if local FM transmissions operated to
time-nuts levels of stability, but I can assure you that air traffic
transmitters are probably not the way to go. Air traffic transmissions
have 25kHz spacings but some allocations have multiple transmitters at
different sites all using the same channel, but frequency offset from
each other to give wider coverage - and of course, with the exception of
VOLMET and ATIS transmissions, the signal is very intermittent.
Your best bet would probably be to get hold of a Thunderbolt as I did,
you can also feed the 10MHz output to a set of dividers if you have
test gear which can use external an external frequency reference - very
David, Milton Keynes, UK (G4IRQ)
On 12/10/2011 09:32, David J Taylor wrote:
> I'm happy with my timekeeping, but I would like to get my frequency
> calibrations rather better now.
> I'm in the UK, and wondering what standard frequency sources may still
> be running. I know about 60 KHz, and that's a little LF for my
> needs. I can't find any routine measurements of its accuracy,
> either. 198 KHz from Droitwich isn't receivable here, and may be off
> the air within a year or two if reports are to be believed:
> I remember in the 1960's listening to MSF on 2.5 MHz, but I only get
> clag on 2.5, 5.0 and 10 MHz now. Is that interference from the
> computers here or are those transmissions now off the air.
> Our analogue TV has gone, so no steady ~600 MHz carriers to check, and
> no colour sub-carrier (which used to be quite precise).
> Leaves me with /assuming/ that the local BBC FM Radio stations are
> accurate, or perhaps the local air traffic transmitters.
> Any thoughts on what I /should/ be able to receive in the UK?
> Any low-cost boards which might give a 10MHz GPS-locked signal?
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