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Old March 19th 10, 11:16 PM posted to sci.electronics.design,rec.radio.amateur.antenna
Joerg[_2_] Joerg[_2_] is offline
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First recorded activity by RadioBanter: Mar 2010
Posts: 23
Default FM antenna curiosity

Richard Clark wrote:
On Fri, 19 Mar 2010 17:42:15 -0500, "amdx" wrote:

Richard, after I read your letter I did a little better checking and found
my signal is not weak it is to strong, I'm getting interference from other
frequencies.
Also I get stations on the wrong frequency.
I went out and collapsed the antenna to minimum about 1/3 of what it was
and
my problem station is perfect and the other station I listen to is still
good. The local
NPR station isn't good though. But I can download the podcast of Science
Friday :-)
Thanks, Mike


Hi Mike,

Normally, a too strong signal is not a problem with FM as FM literally
locks onto the strongest signal and rejects the competitors. This is
not a characteristic of the RF wave, but rather the modulation
employed.

Collapsing your antenna is the same thing as moving it.

Now, as to your experience of receiving signals on the wrong
frequency, that is a classic situation of image rejection being poor
due to the lack of a tuned front-end (something that dissappeared with
the dinosaurs). ...



One solution: Try to get an old Becker car radio. And I mean old, at
least 40 year, the first transistorized ones that could still be
switched to 6V. They used to be standard issue in Mercedes Benzes.

[...]

--
Regards, Joerg

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