julian814 wrote:
All right, I think I might have found the proper place to ask about
this. Back in the 90's when GEnie was still around, they had plans to
convert old AM car radios to shortwave receivers. My old Franklin ACE
500 computer wasn't capable of interpreting the file at the time, so I
didn't get to download it. I'm hoping someone here might know where I
could get the instructions.
Ralph Glatt

Andy writes:
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