starman ) writes:
Mark Zenier wrote:

Here's a suggestion, hit a swap meet (or ebay) and get 1) rf signal
generator and 2) a (digital) frequency counter. When you're lost on
the SR-III, (turn on and) adjust the generator (with the counter hooked
up and working) until you get a heterodyne and then just read out the
frequency.

You can buy a digital frequency display which will work with most any
shortwave or MW (AM) receiver from the following website. Price is about
$60.

www.aade.com

I figured Mark was suggesting a roundabout method because he figured (or
knows from experience) that connecting a frequency counter to the radio
may cause garbage to appear. If I recall, he was replying to a comment
that the Superradio had an advantage in not having any digital circuitry.

I suspect adding a frequency counter may result in digital noise appearing
in the radio, especially since the Superradio is indeed a very cheap and
unshielded radio.

I was going to suggest a crystal calibrator (with digital dividers, one
can get down to 10KHz and count them, yet use a higher frequency to get
the 100KHz points), but then I remembered that it might be more difficult
counting the points without a BFO.

Michael