All computer speakers are amplified. Many of them have very poor immunity to RF. I have sometimes reduced RFI to acceptable levels by winding a couple of turns of the cables through snap-on suppression toroids. Winding several turns through a large ring toroid would be more effective as the snap-on suppressors are really only designed to suppress VHF.
Some computer speakers have such poor RFI immunity that they are probably beyond fixing. One pair I bought made by Logitech hummed even when placed near a cordless phone base unit that probably has an output power of a few milliwatts. The first time I pressed the PTT of my transceiver the resulting noise nearly gave me a heart attack. I gave them to a charity shop. There is a firm (I think it may be the one that makes RigBlaster interfaces) that advertises RFI-proof computer speakers, but I seem to recall the last time they were mentioned on this reflector they were out of stock. ----- Julian, G4ILO. K2 #392 K3 #222. * G4ILO's Shack - http://www.g4ilo.com * KComm - http://www.g4ilo.com/kcomm.html * KTune - http://www.g4ilo.com/ktune.html -- View this message in context: http://elecraft.365791.n2.nabble.com/RFI-PC-Speaker-Hum-tp5116897p5134746.html Sent from the [HAM] mailing list archive at Nabble.com. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
