[time-nuts] Interesting frequency standard project

[EWKehren at aol.com]

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.k9si at 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"  <starcity at plymouthcolony.net>
> To: time-nuts at 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

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