AndyS wrote:
In my opinion, the easiest, most non-destructive way to do this
is to add a converter, using the AM radio as a tuneable IF for
AM transmissions.
A two transistor converter, using a xtal oscillator and a mixer,
can easily do this. Just select the xtal frequency to be about
1000 Khz above or below the middle of the shortwave band you
want.
I am assuming you are only interested in AM shortwave
broadcasts. Any of the other modes would require modification to
the inside of the AM radio....

Anyway, the neat thing about this approach is that no modification
needs to be done to the innards of the AM radio......And you can
still listen to Rush Limbaugh by switching off the converter....

If, on the other hand, you want to modify the AM radio to short
wave without adding anything significant, it depends entirely on
the circuit. In general, you will rewind a bunch of coils, which
means you need equipment for testing and measuring. There are
some AM radio designs that are such that success is extremely
unlikely while others are fairly straightforward ---- it's like asking
"how much does a rock weigh?"
I encourage the CONVERTER approach.... Good luck with your
project. These weekenders can be a lot of fun and very
educational...

Andy W4OAH in Eureka, Texas

Thanks, Andy. I think I've managed to find something a little better
than what I had in mind, anyway - Lindsay books sells a series of books
called the Impoverished Radio Experimenter. I've ordered two of them
that seem likely to have the information I need. My only concern now is
being able to run a tube receiver off of battery power, but I'm hoping
I can figure out something on my own.


Ralph Glatt