"noise"

[mr_doubtfire]

An environmental charity I work for powers a battery operated radio from a dynamo on a stationary bicycle which children can pedal in order to listen to the radio. The trouble is when they do there's a great deal of "noise," I'm assuming it's static, and the radio is hardly audible. Is there an easy solution to suppress the interference without it costing too much?

[Old_Geezer]

Probably good to identify where the noise is being generated and suppress it at source. Failing that if you can identify the frequency range a simple filter somewhere in the signal path of the radio should cut it out.

[The Builder]

Wouldn't the source be the dynamo itself OG?

Is it not the same thing that cars suffered from in the "old" days? Usually, a capacitor is wired across the terminals to lose the unwanted AC voltage.

[Old_Geezer]

Would be my first guess.

[tamborine]

plug the radio into the Nat Grid, pay the license fee & spread the wealth

[Buenchico]

I'd try inserting an RF choke into the power supply to the radio:
http://www.maplin.co.uk/p/rf-choke-22uh-wh31j

[qcumba]

Capacitors across the the positive and negative. You need to find the voltage first then select capacitors

[mr_doubtfire]

Okay, Buenchico, I've purchased an RF choke. Do I wire it in series or parallel with the dynamo?

[Hopkirk]

What licence fee, Tambo?