Joel Kolstad wrote:
"Scott" wrote in message
news
Wouldn't it be easier to use a frequency counter? If one is not available,
but a general coverage HF receiver or transceiver with a digital readout is
available, you could zero beat the oscillator, note the reading on the
display, cause the oscillator to shift to your other frequency, zero beat
that signal, note the display reading and subtract to find the difference in
frequency.


I'm told that 'zero beating' typically has accuracy not much better than some
tens of Hz due to the limited lower frequency response of the human ear... has
anyone tried zero beating a signal from above and below and taking the average
to get what might be a more accurate frequency estimate?


If you have the right kind of AGC you can listen to the noise getting
stronger/softer and go for the slowest variation -- this will get you as
fine a zero beat as you have patience for.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com