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

[howard holden]

I'll concur with Ken's comments. The rise and fall of signal as they go 
in and out of phase is easy to hear. And you can do it either at near 
zero for a direct read, or, with a little patience, with the WWV carrier 
at an audible pitch. You just have to make sure you are coming at it 
from the correct frequency direction in this case, otherwise you'll be 
off something like a Kc or more.

Using that method to make sure my crystal was "on frequency" about 10 
years ago, I came to 47 CPS off of a W1AW frequency measuring test, 
extrapolating off the LM-18 dial. Probably a fluke, but that was also 
with a calibration sheet that I made up for 3.5 to 3.6 Mc, as the one I 
have didn't come with a cal book. It pays to spend some time with your 
meter to see the change per dial setting with change in frequency, as 
the rate does change with frequency. in the 3.5 to 3.6 Mc range mine 
changes an average of 2.08 dial divisions per Kc.

It's certainly good enough for my needs, and I'm using it as it was 
intended. Amazing that 70-plus year old stuff does so well, and with all 
original components.

Howie WB2AWQ/7


On 12/24/2016 10:42 AM, Kenneth G. Gordon wrote:
> 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).
>
>