[Milsurplus] The BC-221N Freq Meter calibration.

[Ken Gordon]

On 3 Feb 2024 at 13:16, David Olean wrote:

> I spent some more time with the BC-221N SN: 3719.    I tried a few
> different coil cover spacings. My first attempt was about 0.082" and
> The freq span shrunk a bit too much, so I shaved it down to 0.072. It
> hardly moved, so I tried just two 0.040" washers and now I am short by
> only about 1.2 divisions. How cool is that. I think I will wait and
> see how it all holds up, but 1.2 divisions out of 4541 divisions of
> travel is pretty darned close in my book.  I'll get the right
> dimension with some fine tuning, and the dial should track
> perfectly.  My new Cal Book should work out great. I'll enter all the
> 10 KHz spacings into a spread sheet and then generate interpolated
> readings between the 10 kHz points.
> 
> Dave K1WHS

Dave (and others):

I believe I still have a computer program here which was originally designed to replicate or 
replace missing calibration books for the LM and BC-221 meters.

It is quite old, and I suspect that modern software will work at least as well, if not far better.

I'll dig it out and send you a copy of it for your perusal, if you are interested.

Just let me know.

Ken W7EKB