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Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders. |
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19th Feb 2020, 6:42 pm | #1 |
Hexode
Join Date: Feb 2008
Location: Wrexham, North Wales, UK.
Posts: 466
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Broadcast frequency standards
I'm looking for a couple of broadcast frequency standards to calibrate my recently restored signal generator. Compared with the BBC signal at 198kc/s it seems to be spot on, but am I right in assuming that this is always reliable?
Also, can anyone recommend other broadcast frequencies in the LW and MW bands that are consistently reliable (and, preferably, fairly powerful)? |
19th Feb 2020, 11:46 pm | #2 |
Dekatron
Join Date: Feb 2007
Location: Lynton, N. Devon, UK.
Posts: 7,088
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Re: Broadcast frequency standards
My understanding is that MW and LW license conditions stipulate frequency has to have max error of 10Hz.
The BBC Droitwich transmitter is linked to a rubidium frequency standard at the NPL so will be far, far better. Any powerful station you can identify - Google should give info, such as frequency of transmission! Doubtless others will comment and confirm or refute! |
20th Feb 2020, 12:42 am | #3 |
Pentode
Join Date: Jul 2009
Location: Roxburghshire, UK.
Posts: 196
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Re: Broadcast frequency standards
Anthorn on 60kHz but there isn't a constant carrier. There are still a lot of frequency standards going about that lock on to it. Or if you want to spend a few quid, buy a GPS locked synth kit from someone like QRP Labs - which would probably render the sig gen a bit redundant!
Cheers, Colin mm1aps |
20th Feb 2020, 11:00 am | #4 |
Nonode
Join Date: Dec 2012
Location: Stockport, Greater Manchester, UK.
Posts: 2,117
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Re: Broadcast frequency standards
All the UK networked transmitters are synchronised within about 50mHz which is 5×10^-8
Examples are R5 on 693 & 909kHz, Absolute R 1215, Talksport 1053 & 1089
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20th Feb 2020, 11:55 am | #5 |
Nonode
Join Date: Dec 2012
Location: Stockport, Greater Manchester, UK.
Posts: 2,117
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Re: Broadcast frequency standards
See also thread Synchronising Transmitters
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20th Feb 2020, 1:54 pm | #6 |
Dekatron
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,724
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Re: Broadcast frequency standards
The above link was corrupted in a way that Microsoft Edge could correct, but Google Chrome could not.
http://https//vintage-radio.net/foru...ad.php?t=73601 this should be UK on all https://vintage-radio.net/forum/showthread.php?t=73601
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20th Feb 2020, 5:02 pm | #7 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,970
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Re: Broadcast frequency standards
I've edited it.
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20th Feb 2020, 6:37 pm | #8 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,902
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Re: Broadcast frequency standards
I think the transmissions that are intended to be useable are MSF at 60kHz then MSF and WWV on 5 and 10MHz
Long and medium waves don't get a look-in. If you want good accuracy then a GPS corrected oscillator is probably the easiest thing to arrange. +/-10Hz on a medium wave transmitter is only +/- 10ppm which isn't too wonderful. David
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20th Feb 2020, 7:47 pm | #9 |
Hexode
Join Date: Feb 2008
Location: Wrexham, North Wales, UK.
Posts: 466
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Re: Broadcast frequency standards
Many thanks for these helpful replies.
I'm glad to report that my old Taylor signal gen is bang on accurate on LW; on MW it is very close at the low frequency end and within about 5pc at the high frequency end. |
20th Feb 2020, 11:21 pm | #10 | |
Dekatron
Join Date: Sep 2010
Location: Cheltenham, Gloucestershire, UK.
Posts: 3,077
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Re: Broadcast frequency standards
Yes, I think pretty much all MW stations will be a safe bet in terms of accuracy when it comes to checking the dial on a typical vintage signal generator. Presumably you used a radio receiver and listened to the beat note of the sig gen and each radio station. I think that method would be OK to use?
Quote:
BBC R5 on 693kHz and Talksport on 1089kHz and the station on 1215kHz seemed to be very accurate although the analyser can only go down to about 30mHz resolution BW before it gets so slow it is unusable. In this mode the analyser is effectively just a big and fast ADC clocked from a reference derived from a decent 10MHz OCXO.
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