[RFI] RFI resistant telephones
Edward F. Douglass
Sun, 01 Dec 2002 09:54:01 -0600
I am new to the list. I have read the last few month's "traffic" but have
not found a thread dealing with telephone RFI, and RFI-resistant telephones
As part of my diagnosis, I need an RFI-resistant telephone in order to
determine if phone company equipment (lightning arrester, RF bypass
capacitors, or other devices) are rectifying my transmit RF and putting
audio on the phone line.
All of my phones are sensitive to RF because in spite of a variety of
chokes and filters, I hear my SSB audio on every phone. Some are less
sensitive than others but they all have objectionable audio on them. Of
course, the audio could be coming from phone company equipment or faults in
my phone wiring as well as my own phones. If either of these happening, no
amount of filtering or choking will solve the interference problem.
The ARRL RFI tech site mentions the Radio Shack ET-171 as a phone that is
pretty resistant to RF. However, my Radio Shack catalog no longer lists
I am aware of the "bullet proof" phones from TCE Laboratories and Pro
Distributors but they cost $80. I would like to find a less expensive test
Can anyone recommend a phone that I could buy at a WalMart, Target, Radio
Shack store (or similar) that is RF resistant? Please specify make and
Or does someone have an RF resistant instrument that I could borrow for
testing purposes? I would be willing to pay shipping both ways.
Finally, has anyone found that re-wiring their residential phone system
with Category 5e data cable has made a significant improvement in RF pickup
to make the cost and effort worth while?
73 de Ed, AA9OZ