Hello All,

[Basically this says, are there any practical alternatives to an air
variable capacitor that a beginner can use in building his first
receiver radio?]

I'm interested in getting my feet wet in building a receiver, but don't
want to buy a 'kit'. I'd like to build a radio that has a knob I can
somewhat tune it with. I've been really looking at regenerative radios
and superheterodynes, although a simple radio is more important than
how well it really performs.

One common theme in almost every 'simple' radio design I can find, is
that they *ALL* use Air variable capacitors. While I'm sure these were
everywhere 20 years ago, going to every major electronics supply house
in Portland, Oregon has yielded me only with small trimmer capacitors,
which AFAIK, will not do for a 'tuner'. I'm aware I can order online
for about 10-20$ and purchase an air variable, but I'd like to see if
any of you have any suggestions on what might work as an alternative?

Varactor diode seemed like a neat idea, although I guess they suffer
from temperature fading. Would this make it impratical for a shortwave
or AM receiver? Can you even make a regenerative radio out of a
varactor? (Actually, I'll try ghetto rigging a red LED for a varactor,
since I don't really care about it being nicely linear, I just want
something with a knob that does something!).

Can anyone recommend any type of reasonably simple radio (simple mostly
as in reasonably low parts count, i don't need an LCD readout) that
could possibly be done with parts that can be had at a reasonably
stocked electronics store. (Much more inventory than Fry's). A knob is
important, I don't want to build one of those ghetto radios with the
coil and a metal bead that I slide along the coil to 'tune' it. Any
other way to use a potentiometer to tune a radio?