Re: Adjacent Frequency AM Reception

[dan.strassberg@att.net]

My problems is not related to geomagnetic storms or to 
WEZE; it's _very_ local (I'd say within 50' or so of the 
house across the street from mine) and it causes 
interference (sounds like a strong open carrier) at a 
number of spots on the AM dial. I've not been able to 
determine that these spots are equally spaced in 
frequency (so they appear not to be harmonics of some 
lower frequency) and the "open carriers" don't seem to 
be modulated by much hum. That is, if I heard a _real_ 
open carrier with that much hum on it, I wouldn't 
suspect problems in the station's audio chain. Bob 
Bittner described a similar problem at his house almost 
40 miles away, so my guess is that each of us has a 
neighbor who has some sort of equipment that puts out a 
spiky spectrum with components fairly close together in 
the vicinity of 1 MHz. Could it be a desktop computer's 
switching power supply? It isn't either of my laptops. 
The noise they produce (mostly from the inverter that 
powers the display's cold-cathode fluorescent backlight) 
affects AM reception only within a foot or so of the PC.

The effect on my reception of quite a few AM stations is 
devastating. When WBIX is on low power during the 15 
minutes between local sunset and Philadelphia sunset, 
not only must I carefully position the radio to null out 
the interference (a tiny rotation of the radio can make 
a huge difference), I must also keep my hand firmly on 
the radio in the vicinity of the ferrite-rod antenna. 
This suggests that the interference has both magnetic 
(inductively coupled) and electric (capacitively 
coupled) components.

The problem affects not only radios in the house but 
also those in my cars. However, if I drive down the 
street in either direction, the interference abates 
rapidly.
--
dan.strassberg@att.net
617-558-4205
eFax 707-215-6367
> At 9:49 AM -0400 5/29/02, Laurence Glavin wrote:
> 
> >  Has anyone else noted this, and what could be causing it...and is it legal?
> 
> Possibly related to the recent solar flares, geomagnetic storms, 
> etc..  It's legal according to the laws of physics, no way the laws 
> of the US or any other earthy entity could do anything about it 
> anyway.