Re: [time-nuts] UK standard frequencies - where?
Hi David, I found it possible to compare down to the mHz region for the 1kHz tones, but of course it requires good propagation, hanging around for the continuous carrier periods of RWM and a disproportionate level of patience! Patience is something I need more of! But in terms of the R8500, I found that adjusting the trimmer to as near as 1 Hz at 15 MHz was quite tricky. A GPSDO is certainly the way to go for a quick, reliable and highly accurate frequency reference - and it's a godsend if you have test gear with a reference input. In fact a pal of mine has recently bought a TS950 transceiver which already has an input for a 10MHz reference - sadly my IC756Pro2 doesn't have that but at least I can check it accurately. Yes, that would be handy. Except that you'll then start wanting to take your reference when going out portable! You'll probably find, like me, that once you have cracked the issue of frequency accuracy you'll start fretting about amplitude accuracy when you test and align things! All the best, David, G4IRQ Yes, I can imagine, but that will have to wait! I was sorely tempted by the spectrum analyser & tracking generator reviewed in the recent RadCom, but I don't think I would use it enough, let alone justify the cost. PS. When locating the GPS aerial, if possible try and get a clear view from W, through South and around to East. That arc is where you'll see the most satellites; from NW through North to NE has poor coverage. Yes, I have four GPS antennas for timekeeping here already, one outside (a Garmin GPS 18 LVC on the roof, sloping towards the west) and three indoor - two Sure and one GPS 18x LVC. In my WXtrack software, I wrote a function which shows the number of satellites visible in a particular quadrant during the day. I also wrote a program which read the messages coming a GPS 12XL I have and plotted the actual satellites seen at this location. 73, David GM8ARV -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] UK standard frequencies - where?
Hi David, I found it possible to compare down to the mHz region for the 1kHz tones, but of course it requires good propagation, hanging around for the continuous carrier periods of RWM and a disproportionate level of patience! A GPSDO is certainly the way to go for a quick, reliable and highly accurate frequency reference - and it's a godsend if you have test gear with a reference input. In fact a pal of mine has recently bought a TS950 transceiver which already has an input for a 10MHz reference - sadly my IC756Pro2 doesn't have that but at least I can check it accurately. You'll probably find, like me, that once you have cracked the issue of frequency accuracy you'll start fretting about amplitude accuracy when you test and align things! All the best, David, G4IRQ PS. When locating the GPS aerial, if possible try and get a clear view from W, through South and around to East. That arc is where you'll see the most satellites; from NW through North to NE has poor coverage. On 13/10/2011 06:18, David J Taylor wrote: The problem with all of these comparative techniques is that you are always dealing with relative error vs finite error. However the result is usually well in excess of that needed for ham ops. Yes, something like 100 Hz at 100MHz is good enough for my current needs, but it's nice to be ahead of the game! Another trick is to load one memory with a 1kHz RWM offset in USB and another with a 1kHz offset in LSB so as to generate a tone for each sideband. You then feed the AF into SpectrumLab and repeatedly toggle between the two memories whilst adjusting the LO. If you adjust the LO so that the difference between the LSB and USB audio tone is at a minimum, that will give you the most accurate setting. Any errors in the sound card will cancel out because you are comparing the /difference /between the two 1kHz signals, any remaining errors will be down to variables within the radio. Hope that helps, 73 de David, G4IRQ An excellent suggestion, David. At one point, I could get both the 10 MHz and 15 MHz RWM signals, and switching between those showed less than a 1 Hz difference in the 1 KHz tone. Barely visible on the Spectrum Lab display (covering about 1200 HZ total on a 1600 pixel wide display). Having said all that, I've now ordered a low-cost GPSDO as it seems that many of these off-air standards may not last too much longer! 73, David GM8ARV ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] UK standard frequencies - where?
The problem with all of these comparative techniques is that you are always dealing with relative error vs finite error. However the result is usually well in excess of that needed for ham ops. Yes, something like 100 Hz at 100MHz is good enough for my current needs, but it's nice to be ahead of the game! Another trick is to load one memory with a 1kHz RWM offset in USB and another with a 1kHz offset in LSB so as to generate a tone for each sideband. You then feed the AF into SpectrumLab and repeatedly toggle between the two memories whilst adjusting the LO. If you adjust the LO so that the difference between the LSB and USB audio tone is at a minimum, that will give you the most accurate setting. Any errors in the sound card will cancel out because you are comparing the /difference /between the two 1kHz signals, any remaining errors will be down to variables within the radio. Hope that helps, 73 de David, G4IRQ An excellent suggestion, David. At one point, I could get both the 10 MHz and 15 MHz RWM signals, and switching between those showed less than a 1 Hz difference in the 1 KHz tone. Barely visible on the Spectrum Lab display (covering about 1200 HZ total on a 1600 pixel wide display). Having said all that, I've now ordered a low-cost GPSDO as it seems that many of these off-air standards may not last too much longer! 73, David GM8ARV -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] UK standard frequencies - where?
The problem with all of these comparative techniques is that you are always dealing with relative error vs finite error. However the result is usually well in excess of that needed for ham ops. Another trick is to load one memory with a 1kHz RWM offset in USB and another with a 1kHz offset in LSB so as to generate a tone for each sideband. You then feed the AF into SpectrumLab and repeatedly toggle between the two memories whilst adjusting the LO. If you adjust the LO so that the difference between the LSB and USB audio tone is at a minimum, that will give you the most accurate setting. Any errors in the sound card will cancel out because you are comparing the /difference /between the two 1kHz signals, any remaining errors will be down to variables within the radio. Hope that helps, 73 de David, G4IRQ On 12/10/2011 13:54, David J Taylor wrote: 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 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] UK standard frequencies - where?
-- From: "David J Taylor" Sent: Wednesday, October 12, 2011 9:32 AM To: "Time-nuts mailing list" Subject: [time-nuts] UK standard frequencies - where? Folks, 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: http://www.guardian.co.uk/media/2011/oct/09/bbc-radio4-long-wave-goodbye 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? Thanks, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk David I would suggest the good old "Thunderbolt" again - works fine here in the south of the UK with an antenna in the loft or just outside of the window. Roy ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] UK standard frequencies - where?
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: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] UK standard frequencies - where?
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. Yes, I can get the RWM on 14.996 MHz - so that's an excellent HF start. 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. OK, but I'm probably OK for the moment. 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. Yes, it's been a bit hit-and-miss, and I suspect that all of the local transmitters were aligned by the same team, perhaps even the same instruments. Quite close agreement, but are they correct? 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 useful. Regards, David, Milton Keynes, UK (G4IRQ) Something like a T/B but using a pre-amped puck antenna would be ideal for here. Many thanks for your help. 73, David GM8ARV -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] UK standard frequencies - where?
You should be able to receive France's Allouis transmitter on 162KHz. It is a 2MW transmitter with a carrier accuracy of 2 parts in 10 to the 12th. I believe it carries a timecode. John H. Most helpful, John. Yes, that's a good signal here and provides a useful checkpoint. Thanks, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] UK standard frequencies - where?
You should be able to receive France's Allouis transmitter on 162KHz. It is a 2MW transmitter with a carrier accuracy of 2 parts in 10 to the 12th. I believe it carries a timecode. John H. On 12 Oct 2011, at 09:32, David J Taylor wrote: > Folks, > > 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: > > http://www.guardian.co.uk/media/2011/oct/09/bbc-radio4-long-wave-goodbye > > 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? > > Thanks, > David > -- > SatSignal software - quality software written to your requirements > Web: http://www.satsignal.eu > Email: david-tay...@blueyonder.co.uk > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] UK standard frequencies - where?
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. 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 useful. Regards, David, Milton Keynes, UK (G4IRQ) On 12/10/2011 09:32, David J Taylor wrote: Folks, 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: http://www.guardian.co.uk/media/2011/oct/09/bbc-radio4-long-wave-goodbye 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? Thanks, David ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] UK standard frequencies - where?
Folks, 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: http://www.guardian.co.uk/media/2011/oct/09/bbc-radio4-long-wave-goodbye 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? Thanks, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
