[ARC5] The not-so humble BC-221/LM-xx frequency meters. - zero-beating with WWV

[Kenneth G. Gordon]

On 24 Dec 2016 at 12:37, Bill Cromwell wrote:

> In recent years I have made my comparisons to WWV using sound card 
> software. We can identify the WWV carrier on the spectrum display and we 
> can watch the secondary standard as we tweak it creep up one side of the 
> WWV pip, reaching the top at *zero beat*. We can't hear zero Hertz but 
> we can see that display quite easily.
> 
> I am not sure how the ancients did it but zero beating to references or 
> standards is *NOT* new.

Well, some regard me as an ancient, and here is how I do it: I listen for the rise and fall in 
the background noise when I check the crystals in my BC-221s against WWV. Using that 
method it is easy to get within a fraction of a cycle/second (Sometimes it hurts to say Hertz).

I eschew the use of a computer to do this, since it takes too long to set that up.

Also, using that "auditory" method, it is easy to hear the short-term drift of both WWV and 
the crystal.

WWV's frequency is affected by propagation and multi-path issues.

That "fraction of a cycle/second" accuracy doesn't hold for much longer than a few seconds, 
but for our purposes, it is plenty good enough.

I might add that I also have a small frequency counter/digital-dial which one can add to 
older rigs like the Heathkit HW-101. That has a non-tweakable 10 MHz crystal oscillator in 
it. When I have both that on and a receiver tuned to WWV, there is an obvious and 
annoying beat of about 1 to 2 CPS. I have to turn that counter off when I tweak the crystals 
in my BC-221s.

Ken W7EKB

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