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From: barry@hprmokg.HP.COM (Barry Fowler)
Newsgroups: sci.electronics
Subject: Re: RFI on telephone
Message-ID: <10040022@hprmokg.HP.COM>
Date: 19 Sep 89 17:17:38 GMT
References: <13681@well.UUCP>
Organization: HP Networked Computer Mfg. Operation
Lines: 28

nagle@well.UUCP (John Nagle) writes:                      

>      I've been receiving two local AM broadcast stations on my
>Western Electric Model 600 telephone.  I fixed the problem by 
>putting a 1000pF capacitor across two terminals within the phone
>that seemed to work.  (Putting it across the phone line didn't help,
>in fact, a dead short across the phone line turned the phone into a
>good radio!)  This seems a hokey solution to the problem.  Is there
>a more respectable one?

>				John Nagle

Oxidized connections can often form semiconductor junctions that
act as detector diodes in the telephone system within your house.
Typical connections are located on the outside of your home where the
2 conductor wire forms a junction to your house.  

The problem, you have fixed puzzles me, however because if the problem
were a result of RFI somewhere from the phone, back, the capacitor shouldn't
have an effect on the problem since the detected signal wouldn't be shunted
by the capacitor.  It appears that the RFI is actually being picked up
at the telephone itself.  To narrow down the possibility, try replacing 
the offending phone with another to see if the problem goes away.  If
it does, one of two things is happening. 1.) The phone is experiencing
an RF overload. or 2.) There is an oxidized connection within the phone that
is detecting the radio signal.

Now, time for the AT&T posters to pounce on me.....   :-)