[time-nuts] ARRL FMT

[Didier Juges]

W4wj at aol.com wrote:
> Hi Didier...
>  
> The "official" readings are taken for the band that is  announced.
>  
> Even though the exciters at W1AW are left on for an extended  period of time 
> before the test, there is some drift during the
> test period.
>  
> I would suggest that you listen on 160 and 40 meters during  the callup to 
> determine wether you have a shot on those bands or  not.
>
>
>
> If you are going to submit in the tenths of Hz, I would  suggest that you 
> only measure during the announced time for that  band.
>  
> Good Luck!!
>  
>  
> 73, Don, W4WJ
>   
When measuring a single CW carrier, I would use the 3586A in direct 
mode. Its counter has 0.1 Hz resolution, and it has an Ovenair OCXO that 
has specs equivalent to the HP 10811 (2e-7/year). Unless I get my GPS 
disciplined oscillator working by then, I'll be lucky if I am able to 
calibrate it within 0.2 or 0.3 Hz against WWV at 10 or 15 MHz, that will 
get me within 0.1Hz or so at 3.5 MHz. That should be a no-brainer. 
Greater accuracy is probably not achievable because of atmospheric 
variations, the rest will be luck.
I think I will run the 3586 set to WWV with my GPIB logging software for 
a few days to see what kind of variations I get during the day and try 
and find the best time to calibrate.
Also, we have the cal lab people (company called TMI) coming next week 
as they do twice a year to calibrate a bunch of instruments on site 
where I work. I am trying to find what kind of frequency standard they 
have, but I may bring the 5370 and ask them to check the time base. We 
have a bunch of microwave gear that needs to be calibrated to factory 
specs, traceable to NIST per MIL-STD, so I would guess they have to have 
at least a good rubidium or a GPS locked reference.
If I get my GPS working, I would try John's method. He has done a good 
job documenting it. Unfortunately, while I have a bunch of machines 
running Linux, they all run in the command mode, so I can't use the 
graphical spectrum analysis software he is using :-(

Didier KO4BB