Yes, it is possible for RF to get into the audio section of your telephone
without getting into the outgoing audio.
The cure would be the same as any other type of telephone interference --
keep the RF out of your phone with common-mode chokes. You can either use
the filters sold by Radio Shack (manufactured by K Com) or can use external
ferrites. (F-140-43 probably a good choice -- try about 10 turns). You may
have to filter the line, the handset and any power-supply connection to the
phone.
General info about telephone RFI is found at:
http://www.arrl.org/tis/info/rfitel.html
73,
Ed Hare, W1RFI
ARRL Laboratory Supervisor
225 Main St
Newington, CT 06111
Tel: 860-594-0318
FAX: 860-594-0259
Internet: w1rfi@arrl.org
ARRL Web: http://www.arrl.org
ARRL Technical Information Service: http://www.arrl.org/tis/
-----Original Message-----
From: Eric Rosenberg [mailto:wd3q@erols.com]
Sent: Thursday, November 02, 2000 1:50 AM
To: rfi@contesting.com
Subject: [RFI] 1-way telephone interference
Ran into an interesting situation this past weekend during the CQ WW
contest.
Running 100w to a yagi or dipole, my wife consistently heard me on the
phone (garbled), while the people on the other end did not.
Is this normal? I never thought to ask the folks on the other side of
the call this question, so I don't know if this is new or not.
Any ideas or suggestions for a cure? I'm about to add an amplifier, so
I want to nip these issues in the bud before they crop up!
Thanks in advance,
Eric W3DQ
Washington, DC
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