Hi Jim,
In answer to your first query re. my use of the word "incredibly", well, to ME
at least, it truly was: we'd all spent the better part of the evening
attempting to solve this neighbour's telephone RFI, and I was absolutely aghast
when I couldn't hear a thing whilst seated beside the phone, yet she claimed
that she could, standing beside me!
I really & truly thought that that either (A) she was a certifiable nut case,
or that, (B) she revelled in all of the attention that she was getting, & was
telling a fib! It was incredible to me because I never in my wildest dreams
ever expected that the handset cord would act like a loaded antenna, fully
extended like that. I imagine its natural resonance was somewhere in the
10-meter band, too!
And FWIW, the noise was NEVER totally eradicated when the cord was straightened
like that---even with ferrite devices installed at both ends of it. It was
"quiet" only when the cord was "bunched up"---straightened out, it acted like a
perfect antenna.
~73~ de Eddy VDE3CUI - VE3XZ
On 2012-09-15, at 12:35 PM, Jim Brown wrote:
> On 9/15/2012 5:22 AM, Eddy Swynar wrote:
>> Incredibly, the coiled handset cord while I was seated was immune to
>> RFI---but as soon as it was outstretched, it must have acted like a resonant
>> loaded vertical on 10-meters!
>
> Why do you use the word "incredibly" to describe simple antenna action?
>
>> No amount of handset bypassing / filtering ever eliminated the RFI in the
>> cord's uncoiled state
>
> This might have succumbed to a couple of turns around a #43 or #31 ferrite
> core placed either on the cord to the handset, or to the telephone line cord.
>
> FWIW, telephones are notoriously bad for RFI.
>
> These RFI "war stories" are quite useful, including Pete's about those light
> switches. There's clearly something about the construction of those switches
> that is allowing noisy leakage current when the switch is off, and interior
> house wiring is radiating it.
>
> 73, Jim K9YC
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