In the seventies I did for some friends that had FCC First class licenses a counter that on the input had three J/K F/F's to subtract the IF from the LO. They modified receivers including running the IF in to saturation and they certified stations without going there.. I think measurements had to be done on a monthly basis. Since they where also HAM's they also used them on frequency contests. Bert Kehren In a message dated 7/5/2014 12:56:24 P.M. Eastern Daylight Time, alw.k...@gmail.com writes:
As stated AM stations in US must maintain 20 Hz accuracy. Most are well within that tolerance. I have measured many AM station's frequency as a function of my employment before retirement. Now comes HD radio. While the merits of HD AM radio are very much open to debate, one benefit is that the equipment for HD is GPS locked. If you can find an HD AM station you can probably bet they are very close to being on frequency. The ones I have measured have been right on and push the limits of my test equipment. Al, retired, mostly AKA k9si > Date: Sat, 05 Jul 2014 06:20:36 -0400 > From: "Dale H. Cook" <starc...@plymouthcolony.net> > To: time-nuts@febo.com > Subject: Re: [time-nuts] Interesting frequency standard project > > At 06:27 PM 7/4/2014, Hal Murray wrote: > >>>... we have no requirement for that level of stability on the MW >>>broadcasts. >> >>How stable are they? > > That varies greatly from station to station depending upon what > transmitter they are running. Note also that compliance with the 20 Hz > accuracy requirement varies so you would only want to use stations owned > by companies with a good record of compliance with Part 73. > > Dale H. Cook, Contract Engineer, Roanoke/Lynchburg, VA > http://plymouthcolony.net/starcityeng/index.html _______________________________________________ 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.