[Elecraft] Frequency Reference (was: Mini Modules)

[John A. Magliacane]

> John,
> Please share your design with the "group" once it matures.  In addition to 
> the W8DIZ design, I'm aware of this one:
>         http://www.aade.com/freqstd/freqstd.html
> tnx,
> Steve
> aa8af

I'll do my best, Steve.  I wasn't aware of the circuit you pointed out,
but what I have has some similarities.

My K2-inspired WWVB receiver is developmental at this point, but I was
able to see 4 volts pk-pk on the output of my I.F. amplifier this afternoon
during the Class-M Solar Flare induced radio "blackout".  WWV was in the
noise, while my 10 MHz reference was locked solidly to WWVB, over 1600
miles away.

Some folks on the list have written to me indicating an interest in
either locking an HF oscillator to WWVB as I have done, or simply comparing
a TCXO to WWVB to determine its error.  In some cases, the latter might
be a slightly better approach.  It all depends on QRN, and the parts
one has available.

WWVB reception can be quite a challenge, especially here on the east coast
where signals are a bit weak.  As is the case of ALL radio communications,
signal-to-noise ratio is the limiting factor in communication effectiveness.

The biggest hinderence I've observed in WWVB reception appears to be the
1000th harmonic of power line noise because it s-l-o-w-l-y sweeps back
and forth across WWVB's frequency.  (Now I understand that 60 Hz is an
AVERAGE.  The power line frequency seems to constantly move around,
and observing the 1000th harmonic against an atomic standard in this
manner shows up the error quite easily.)  Placing an electrostatic
shield (tin foil) around my loop antenna might help.  Employing high
receiver selectivity doesn't always help, since noise impulses cause
resonant circuits to ring, sometimes totally clobbering the desired
signal in the process.

WWVB disappeared for a while this afternoon.  I suspect a transmitter
or antenna problem.  Either that or someone at NIST is messing
with me.  :-)


73, de John, KD2BD


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