For the fun of it...

[Resident Loser]

...there's another thread (in another forum) re: RFI in the form of unwanted program material...but alienating rhetoric precludes my further participation in it...However, I did see some statements that lead me to believe there are some misconceptions on the subject.

In my nearly forty years of telecom experience, radio reception on low powered or even unpowered systems isn't all that uncommon...ask anyone even slightly familiar with a crystal radio; same basic concept. It uses a minimum of components including the "cat's whisker" (which actually works due to it's imperfect contact junction*>see below<) and zero power source to snatch the all-pervasive AM signals out of thin air...

AM transmitters are the usual suspect...without gettin' all techie about it, trust me, it's a fact...

At this point I'll interject with some salient quotes from the FCC:

Common Causes

Before you can resolve an interference problem you must isolate the actual interference source. Interference originates from many sources - the equipment itself, your residence, or the neighborhood.

The two most common causes of interference are transmitters and electrical equipment. Communication systems that transmit signals (transmitters) are capable of generating interference. These systems include amateur radios, CBs, and radio and television stations. Electrical interference may be caused by power lines or electrical equipment in your home.

And this is probably the best part, particularly for those hi-end folks who subscribe to the minimalist mythology:

Transmitter Interference

Transmitter interference is normally caused by the actual design of the (interfered-with) equipment itself. Many manufacturers do not protect internal wiring with adequate shielding or sufficient filtering, so the interfered-with equipment is susceptible to receiving unwanted signals - interference.

*The source may be as simple as a frayed wire that connects your speakers to an amplifier. A faulty wire can act as an antenna that will carry interfering signals. Check the incoming wire from your outside antenna for any damage or corrosion. Replace any twin-lead cable with a coaxial cable - which offers the best protection from all types of outside interference.

To determine whether the interference is coming from the interfered-with equipment itself, unplug one component at a time on the interfered-with equipment or on other equipment to see if you can isolate the source. Also, disconnect other electrical equipment (answering machines, telephones, fax machines, etc.) one by one. If the problem goes away when the device is disconnected, you have found the source - the device itself.

Check to be certain everything that needs to be grounded is, including AC outlets...Ex Post Facto: And when I say grounded, I mean the ground leg of the buildings electrical system must be tied to a cold water pipe, a ground stake or the commercial AC ground...If one disconnects a ground in order to eliminate some interference to me it's an indication that the "true" ground has been interupted somewhere along the line and that the bulk of the grounding effect is actually an atmospheric ground which will have a difference in potential to an earth ground as measured with a VOM...it's also a dangerous situation.

Many times it's simply wire or device orientation that acts as an antenna...try moving the interconnects...which BTW should be as short and shielded as possible...Even devices connected via the mains and on the same circuit can be part of the problem...it can be a cumulative effect that actually "fine tunes" your unwanted "receiver"...Perhaps unplugging the whatever-it-is in the next room may have an effect, particluarly in older apartments having the bare minimum of circuit separation...Even the proximity of your body or that of your significant other or pet can play a part...

Coiling wires can further exacerbate the problem...

Low pass filters with rejection characteristics of frequencies above 600khz can be purchased/modified/DIYd...

jimHJJ(...FWIW...)