[ARC5] Unusual BC-221

[Roy Morgan]

On Mar 4, 2015, at 6:47 AM, Bill Cromwell <wrcromwell at gmail.com> wrote:

> .... My calibration has evolved to using one of two computer sound card DSP  programs and WWV.

Bill,

I’d like to know enough of the details to be able to make such a setup here.

> I set up my sound card program and radio so I can hear and display the WWV carrier - not at zero cps on the sprectrum but usually near 1 kc. The exact tone matters not.

Do I understand you are feeding the audio from the LM earphone jack to the audio input to the computer?  Is it an audio spectrum analyzer program on the computer?  (I don’t have one but can find one -I use an Apple computer here. I do have FLdigi - maybe that would work.)

> The xtal marker from an LM (or other source) is brought into play.

So you turn on the crystal calibrate function.

> Tweaking the xtal onto WWV will show the pip for the xtal creeping onto WWV's carrier

And there’s an antenna feeding the RF input/output of the LM so it can pick up the WWV signal off the air?  Oh, you mention a receiver below: the LM signal and the off the air signal of WWV mix in the receiver?  So the sound card gets the audio from the receiver?

> and then a moire pattern will be seen advancing up the slope to WWV's peak.

Maybe you are using the BFO in the receiver and getting a 1 kc beat note from the carrier, then the LM signal is adjusted to match that same beat note, whatever it might be.

> When it reaches that peak - "on frequency" the moire pattern will stop crawling and stop "wriggling". Never mind about calibration of the receiver, the sound card, or anything else. If any of that moves WWV will move with it and will will still be the "target”.

You mean the beat note produced from the WWV carrier in the audio output of the receiver?

> After all these years a good LM (or 221) is hard to beat.  They do tricks a digital frequency counter can’t.

As I mentioned, I have a very nice LM here, with correct cables and power supply.  Just as old as I am!

Roy 

Roy Morgan
k1lky68 at gmail.com
K1LKY Since 1958