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Picking up Radio Frequency


Vladi
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I have discovered last night that I am hearing a radio station thru my speakers when listening to the CD, haven't yet identified what radio station, but it is different than what my built-in-receiver tuner is tuned in. The _strangest_ thing is that it is only audible at certain amplification -- it is heard at -15dB, reduces at -14dB, further reduces at -13dB, inaudible at any other amplification. The CD is on pause.

All in all, it is very weak, comparable to -80dB.

What can be causing this? I am just curious, although I never listen to that high volumes and I cannot hear it at any other amplification.

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Do you only hear it when CD is selected? Do you hear it when the CD player is off, but CD is selected on the receiver? Can you pick up the same station on your Tuner? This would tell you how far away the station is.

Play around and see if you can determine exactly where the interference is entering your system. Typically CB and Ham I/F comes in to the receiver through the speaker wires, and can be eliminated using bypass capacitors at the receiver end of the wires. If it is getting into your CD player, try changing the interconnect cable length and see if it goes away. If you can borrow another brand of CD player, try that also.

Let us know how you come out. It might help someone else later. Good Luck.

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sounds like as you turn up the volume the noise from your receiver &/or input electronics is overcoming the rf.

i've got the same on my rear cornwalls w/ about 30ft of cable runs. i'm going to contact the engineers at the radio station & see if they'll supply some ferrite cable attachments. they better or i'll contact the fcc. 16.gif

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I use "Analog Direct" when playing CDs thus using the CD player DAC, there is no noise, bearly bearly audible at -10 and above. As compared to when the signal goes thru the receiver processors, then yes, the noise is overcoming the RF at -20dB and above.

I've been thinking about this all day ...

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i talked to an engineer at the radio station about my rf in rear speakers problem. he seems to

think its being picked up in the pre/pro or amplifier, & mainly because i'm floating my grounds w/

cheater plugs.

but this doesn't make sense to me as right now i'm getting the rf fairly audibly only from one rear

cornwall, though slightly from the other cornwall, as well as the LF klf-30 w/ totally different biwire

cable.

so i'm going to have him supply me w/ some ferrite attachments 1st, though he says they won't

help. that's easier than messing around unplugging everything in troubleshooting.

the real problem is the radio station. they're only a few blocks away, & i never noticed a problem

until they switched frequencies & I bet upped the power output.

the neighbor mentioned he's getting it on his speakers too & they've already been here a few times

getting it off my phone lines as well as all over the neighborhood. & to do the phones they used

filters & line attachments. don't know why he's so sure the ferrite attachments wouldn't help on

the cables.

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  • 4 weeks later...

I have had a similar situation. Mine would happen after I shut the system down. Once everything was quiet I could hear a religious program preaching some pretty heavy stuff coming thru my speakers. The strange part is that we don't have a station like that in the area. It would only last about 15 - 20 seconds then fade out. I was using an Adcom amp and preamp, tried changing outlets, grounding, etc. Maybe an omen????...STRANGE!

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a tech at b&k told me wrapping aluminum foil around the speaker cable can work on rfi too. still need to try that myself. will try wrapping the foil on the cable near the amp to start.

thing is i only hear the rfi from the rear speaks w/ the long monster Z cable runs when the system is turned off. once the system is on it takes out or overcomes the rfi. so no real biggy here.

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