[K6BW] Another gem from QRP-L, this one will leave you guessing.

[Bill Smith]

Oops, that message was to Dave Benson, K1SWL. Oh man, I know better than
that.

I came across a 507kHz quartz crystal in my skunkbox this morning. I
was thinking; a "x7" saturable magnetic multiplier would put me on
3535kHz. Hmm, I seem to be talking myself into a project. A
half-Fessenden? Now, if only I can remember where I put that bag of
tiny, high-permeability ferrite toroid cores then I might be on a
roll. :o)

I forgot to mention that Lowfers, as well as our cousins across the
pond on 136kHz, might be interested in this RF alternator business.

Also, in reference to the URL for the 0AD receiver given in my last
post; my notebook shows that last year at this time I built a Tayloe
mixer for LF NDB listening. It only amounted to a CD4052B connected as
a Tayloe mixer, switched by my bench signal generator via the usual,
dual FF quadrature circuit. I hooked two piezo earphones directly
across the mixer output (no AF amplification) to create a modern
equivalent to the very early heterodyne receiver (using an arc or a
small RF alternator for the heterodyne signal). You might also think
of it as a "crystal" receiver for CW with a nearly ideal detector.
What was especially fun was the binaural output produced in the two
piezo earphones. Anyway, I logged a surprising number of US and
Canadian beacons with this "passive" setup with an antenna made from a
50 foot hank of wire, tied to the nearest tree.

A nice resource on the subject of early RF alternators can be found in
Google's great "full-text" books. This is just a sample of all the
great reading material they've put up for us. Gosh, I'm so thankful to
live in the age of the Internet!

http://books.google.com/books?lr=&q=Wireless+Telegraphy&btnG=Search+Books

Okay, back to my Hobbit-hole.

Mike, AA1TJ