[AMRadio] Telephone Wiring RFI Treatment


Clarke, Tom AIR4.0P NATOPS frederic.clarke at navy.mil
Tue Dec 19 15:50:09 EST 2006


 


Tom Clarke
NATOPS Program Support
USN/USMC National Airworthiness Office
Naval Air Systems Command, AIR-4.0P
(301) 995-3793/DSN 995-3793
Fax: (301) 757-6599
Cell (301) 904-2053
frederic.clarke at navy.mil




Here's one for those wishing a break from the current hot topic!

I need to do some maintenance on the telephone wiring in my house in
order 
to cure a hum that is now constant on all phones.

While I'm at it, I'd like to take appropriate measures to eliminate, or
at 
least reduce the rfi that occurs whenever I operate on 80 or 40 meters
with 
any mode.


Which ferrite beads or filtering should I use, and should I place any
such 
devices on the house side of the entry box rather than, or in addition
to at

the connection point for each phone?

The rfi was present before the hum appeared, so I doubt curing the hum
will 
cure the rfi, although it certainly might at least reduce it.



Mike Duke, K5XU
American Council of Blind Radio Amateurs

-------tom sez-------------
Hi Mike,

The last time I had hum on the phone it was caused by a water intrusion
problem on the telco line outside the house.  The way to check if it is
your problem or theirs you may have already gone through this drill,
sorry), is to plug a phone into the interface box on the outside of the
house, which will isolate all the house wiring from the telco line.  If
there is hum, give the telco folks a call.  If the hum is inside, start
isolating things inside until you find it. 
Good luck in your search.
73 Tom/W4OKW



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