How do I catch radio waves with a guitar amp?

Answer 1

The radio signals a guitar amp makes are not a fault of the amplifier. Rather they are a result of unshielded instruments, effects pedals or cables which are connected to the amplifier. Most likely it is an Electric Guitar's pickups which are causing the interference. To prevent this you need to either get new pickups for the guitar which are shielded or you can modify your existing hardware with RF (radio frequency) shielding. This is done by placing copper film around the pickups, the copper film should not be placed between the pickups and guitar strings. This should prevent any radio signals from getting into your guitar's signal path.

Answer 2

An audio amplifier like your guitar amp cannot do this by itself. The highest frequency it can handle is about 20KHz but radio waves are in the MHz range or higher.

You will need to connect a radio receiver to its input (one way to do this is to build the receiver yourself as described in the Expert Answer above). Purchasing an off the shelf "component" radio receiver and connecting it would be easier.

Answer 3

-- Get a long piece of wire to use as an antenna.
Hang it from a place near the guitar-amp input, to any other convenient place.
As soon as you have a wire hung up, it's catching radio waves.
The only trick is to build something that let's you hear them.

-- Make a coil of fine, insulated wire.
You can wrap 50-100 turns around a pencil.
Scrape the insulation off of the ends, to connect the ends of the coil to other things.

-- Go to the store and get a small-signal diode.
I can't name the store here, but it rhymes with Fraidy O'Slack.
The small-signal diode will cost somewhere from maybe 50¢ for one,
up to maybe $3 for a bag of 20 assorted ones.

-- The input to the guitar amp is built for a plug that has 2 contacts for 2 wires.
One wire usually carries the signal from the instrument ... call that the 'hot' one.
The other wire goes to the shell of the socket. It's the 'ground' connection.
If the wire from the instrument is shielded, the shield connects to ground.

-- Connect the coil, and one end of the small-signal diode, to the amp end of the antenna wire.

-- Connect the other end of the small-signal diode to the 'hot' contact of the amp input.

-- Connect the other end of the coil to the 'ground' contact of the amp input.

If you get lucky, you'll hear the programs of all the local AM radio stations, all mixed together.
Some will be louder, some will be softer, depending on your distance from each station, and
on the power that each station is using to transmit.

Improvements:

-- Try different numbers of turns of wire for the coil.
(I mean 20 or 30 turns more or less, not 1 or 2 turns more or less.)

-- Go back to Fraidy O'Slack and get some ceramic capacitors,
with ratings of maybe 500 pF and down.
These are cheap too.
They may even have a 'variable' capacitor, with a twisty shaft in the middle,
that you can twist and make it anything between maybe 50 - 500 pf.
If you see one, you should buy it.
Any capacitor you get has 2 wires coming out of it, or 2 places to connect wires to it.
Connect one end of the capacitor to each end of the coil.

Good luck !