Question re: WWV fqy
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Please settle a debate among friends..
How accurate are the WWV 5, 10 and 20 Mhz frequencies? I'm saying 0.1ppm, my friend says 1.0 ppm. Looking on the NIST page I get lots of info about time accuracy. Couldn't find the info on frequency accuracy. A link, if possible, would be nice. Direct email is OK (avoids inflating the list) Thanks. -- Dave G KK7SS Richland, WA KX3 #097 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Dave,
The signal starts out good to 10EXP (-13). That is much better than 0.1ppm. There will be inaccuracies due to propagation - see http://www.febo.com/pages/hf_stability/ for one analysis. The author of that page suggests that an allowance of about 0.5 Hz is reasonable, and based on that the received accuracy of 10 MHz WWV would be 0.05 ppm if my math is right. 73, Don W3FPR On 8/21/2012 3:15 PM, Dave KK7SS wrote: > Please settle a debate among friends.. > How accurate are the WWV 5, 10 and 20 Mhz frequencies? > > > I'm saying 0.1ppm, my friend says 1.0 ppm. > > Looking on the NIST page I get lots of info about time accuracy. > Couldn't find the info on frequency accuracy. > A link, if possible, would be nice. > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Dave KK7SS
As transmitted, frequency error is less than 1 part in 10 to the -12th.
As received, due to Doppler error and other ionospheric issues, and depending on how you go about the measuring process, something like 0.1 PPM is about it. Maybe a hair better if you have excellent propagation and you go about the comparison process correctly. Maybe 1 PPM off-the-air if you are doing a quick and dirty comparison, such as watching the S-meter swing around. It's not at all uncommon to see a few tenths of a Hz short term Doppler shift on WWV at 10 MHz during unstable propagation conditions. Jack K8ZOA On 8/21/2012 3:15 PM, Dave KK7SS wrote: > Please settle a debate among friends.. > How accurate are the WWV 5, 10 and 20 Mhz frequencies? > > > I'm saying 0.1ppm, my friend says 1.0 ppm. > > Looking on the NIST page I get lots of info about time accuracy. > Couldn't find the info on frequency accuracy. > A link, if possible, would be nice. > > Direct email is OK (avoids inflating the list) > > Thanks. > > > -- > Dave G KK7SS > Richland, WA > > KX3 #097 > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Don Wilhelm-4
My Thanks to all that answered..
My friend thinks his Txcvr is off frequency. He is apparently way off on 2M... I've suggested using WWV @ 15 or 20 Mhz to calibrate. I think that will be accurate enough. I have a XG3 on the way, and may use that ... I'm sure not going to let him use it on his own <Grin> -- Dave G KK7SS Richland, WA KDX3 #097 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Exactly, you might not get it back!! :-) Mine has been a very handy
device, esp., with the K3/P3 for aligning stuff. 73, Bill K9YEQ -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Dave KK7SS Sent: Tuesday, August 21, 2012 3:33 PM To: elecraft_mailman.qth.net Subject: Re: [Elecraft] Question re: WWV fqy My Thanks to all that answered.. My friend thinks his Txcvr is off frequency. He is apparently way off on 2M... I've suggested using WWV @ 15 or 20 Mhz to calibrate. I think that will be accurate enough. I have a XG3 on the way, and may use that ... I'm sure not going to let him use it on his own <Grin> -- Dave G KK7SS Richland, WA ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Dave KK7SS
Dave,
You didn't say what Txcvr your friend has... The method for adjusting the master oscillator will vary, of course. As for a frequency reference to check against, WWV at the highest freq he can receive is the best most people have available. As for using the XG3- No. It is an excellent signal -level- source, but not a particularly good frequency reference (+/- 50 ppm spec). 73, Bruce, N1RX > My friend thinks his Txcvr is off frequency. > He is apparently way off on 2M... I've suggested using WWV @ 15 or 20 Mhz > to calibrate. > I think that will be accurate enough. > I have a XG3 on the way, and may use that ... > I'm sure not going to let him use it on his own <Grin> ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Jack Smith-6
Use the highest freq WWV signal you can get good reception on, and be
certain that you do it during one of the no audio periods. All WWV's are not created equal either. The 2.5 and 20 MHz show an expected spectrum of carrier plus either 500 or 600 Hz sidebands, and the 100 Hz IRIG-H timecode subcarrier right around the main carrier. It appears that these two transmitters use low level modulation and highly linear amplifiers. 5, 10, and 15 MHz use the same modulation stream but are high level modulated class-C PA's. If you look at their spectra, you will see fairly strong harmonics of the 500/600 Hz tones, and the tones and all the harmonics will be modulated with the 100 Hz IRIG-H time code. So far as I can determine, all the WWV frequencies start out at 10^-12 or better. 73, Fred K6DGW On 8/21/2012 7:53 PM, Jack Smith wrote: > As transmitted, frequency error is less than 1 part in 10 to the -12th. > > As received, due to Doppler error and other ionospheric issues, and > depending on how you go about the measuring process, something like 0.1 > PPM is about it. Maybe a hair better if you have excellent propagation > and you go about the comparison process correctly. Maybe 1 PPM > off-the-air if you are doing a quick and dirty comparison, such as > watching the S-meter swing around. > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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