I was told that more 'grounding' of the phone cable would help reduce the interference on phone cables that pick up radio signals. Is this true??
We have a situation where in a house the phone line picks up faint radio signals on it, and I'm not really sure how to stop it. its even been disconnected from the main line feeding the house and yet it picks up the radio signals.
Anyone have any experience in dealing with this?? And how to correct it??
Most phones with amplifiers in them will have an AM detector diode at its input to the amplifier, this makes a great demodulator for AM radio signals when they are strong enough on the phone lines and sometimes just the phone itself if powered by a wall outlet, many cheep phones don't have much if any RFI filtering and can be the source of the trouble, trying a different phone will sometimes show this, other remedies start with a little trouble shooting, using the receiver part of a good toner which also uses an AM detector diode before an amplifier, you can see (or hear) which phone cables are affected, by placing a phone RFI filter at the demark and at each jack you can eliminate almost all of it, these filters can be purchased at most electronic part supply houses, sometimes Radio Shack has them in stock, the tunable ones can be dialed in with dip switches for the AM band (530kz-1650kz) you can also get them off a phone truck if you see one in the area, (My first choice) as they will just give them to you since your saving them the time to trouble shoot this problem
We have one AM radio station that beams its signal right across two neighborhoods, and it can even affect some garage door openers like a Genie, It gets into the digital signal for the safety eyes, I use the same phone RFI filters for them also, as well for networks with speed problems in this area.
Also if customer has satellite TV, and the receiver is using a phone line for PPV, try disconnecting this line from the back of the satellite receiver, if this clears it up, put a RFI filter in that phone jack, those satellite dishes love to bring in this AM signal and transfer it to the phone lines.