[NLRS] Fwd: Fw: [MNDX] WWV Reference

[Gerald]

On Sun, 2006-01-29 at 19:30 -0500, W0ZQ at aol.com wrote:
> 
> Here is a note from Ford, N0FP, regarding a WWV reference.   If  you have any 
> questions, contact Ford directly.
> 
> 73,  Jon
> W0ZQ
> 
> 
> In a message dated 1/28/2006 8:49:07 P.M. Central  Standard Time, 
> ford at cmgate.com writes:
> 
> Jon,
> 
> I thought others may be interested in this little gismo.   I posted it to the 
> personal space at my ISP.  Perhaps you can post it on  NLRS if you think 
> there might be interest.  If anybody has any questions,  they can contact me  
> directly.
> 
> Thanks
> 
> Ford-N0FP
> ford at cmgate.com
> 
> 
> -----  Original Message ----- 
> From: "Ford Peterson" <ford at cmgate.com>
> To:  <MNDX at yahoogroups.com>
> Sent: Saturday, January 28, 2006 8:28  PM
> Subject: [MNDX] WWV Reference
> 
> 
> >I finally got it done  today.  The WWV calibration instrument seems to work 
> pretty dang good if I  might say so myself.  
> > 
> > When I put any decent antenna on  this instrument during the day (40M 
> dipole, 80M vertical, whatever) I get a nice  10MHz output at about -20dBm, which 
> is more than adequate to trigger my  frequency counter.  Then, using the 
> trimmer on the back of the counter, I  can adjust it to exactly 10 MHz.  As long as 
> the announcer isn't gabbing,  the process works pretty slick.  
> > 
> >  http://members.ll.net/ford/10%20MHz%20Frequency%20Standard.htm
> > 
> >  The guy I talked with at the ARRL TIS department said that the system 
> isn't that  accurate due to skywave propagation.  Apparently, phase inversions can 
>  occur and jumble up the signal.  So we talked about it a while and came to  
> the conclusion that the maximum inversion was on the order of maybe 1 cycle 
> out  of 10 million cycles.  Lemmeseeherenow....  My instruments are only  
> accurate to a reasonable number anyway.  And he's talking about 1  Hertz!  I think I 
> can live with that!
> > 
> > Ford-N0FP
> >  ford at cmgate.com
> 
Consensus has been for decades that if you check WWV on HF the same time
every quiet propagation day for a month you might get a result of a part
in 10^7, 1 Hz per 10 MHz. And that may be better than your counter
crystal. My house standards are a couple orders of magnitude more stable
so I use WWVB on 60 KHz to check them and then I think I see propagation
variations in a short time that I use for checking.

These days the handiest way to precision frequency is using GPS. The 1
pps outputs can be 4 or 5 orders of magnitude more precise than WWV as
received at 10 MHz. There is a commercial box or two, HP-2801A seems to
be popular though touchy. There was a circuit in the most recent Eastern
VHF Conference Proceedings using the 10 KHz output from a Rockwell-
Collins GPS board and not a whole lot of circuitry to stabilize at 10
MHz crystal oscillator and Luis Cuipedo (sp?) has boards for doing that
with the 1 Hz output of most any GPS.


-- 
73, Jerry, K0CQ
Dr. Gerald N. Johnson, electrical engineer
All content copyright, Dr. Gerald N. Johnson