Recording freq. counter

[K6JEK]

I'm looking for a recording frequency counter to make my next run at a drifty VFO easier.  I thought in this day and age there surely must me some cheap little box I can hook to my PC to drop the frequency into a file at intervals, either that or a standalone frequency counter with a PC interface, one that I can acquire for less than an arm and a leg.

I've yet to find either. I must be looking under the wrong rocks.  How do you real engineers do this?

Jon

[WA1GFZ]

Many counters have an IEEE488 interface that could be tied to a computer to sample the frequency and drop it in an excel file. I think newer counters have USB interfaces. Another option would be a Reference or some stable source into a mixer with the VFO as the other input. The third port of the mixer could go into a sound card to measure the difference frequency. Another option run the VFO through a string of dividers and divide the frequency down to audio and send it into the sound card.

[WU2D]

Jon,

Here is a crazy idea.

There is a lot of shareware out there that is based on your computers soundcard. If you are willing to use a secondary standard method rather than direct counting, this could work.

Product Website: http://www.virtins.com
Download PC version: http://www.virtins.com/MIsetup.exe
Download Pocket PC version: http://www.virtins.com/PocketINSSetup.exe
Video Demo: http://www.youtube.com/watch?v=S9HAENzC7qw


The secondary standard in this case is a stable oscillator that the VFO is compared to. The old BC-221 does this with its zero beat method. You could make something similar with a TCXO and a product detector on a chunk of proto board.

If you had a drift-free receiver like a superpro you could use that

In simple terms, using a receiver with a BFO we tune so that the VFO is produces a 5 kHz tone which is sent into the sound card. 5 kHz represents start frequency offset. (I assume that you measure the start frequency with your counter and by hand enter it into the spreadsheet) Now activate the frequency counter logging function. As the VFO runs it will cause the 5 kHz to go up or down or both over time.

Fix everything in excel later.

Mike WU2D