wab@Rational.COM (Bill Baker) (04/03/91)
I have a portable stereo that I use at work (Panasonic DS20 if it makes a difference) and I want to improve the FM reception (the AM is hopelessly hashed from the EM leakage from my monitor). It has a standard factory telescoping whip antenna, and I've made the rounds of the local stereo stores asking for some way of connecting an aftermarket antenna to the whip antenna mounting (it's removable). No one has a clue how to do this. My question is, how is the mounting for a whip antenna different than the standard antenna connector on any stereo receiver? Is there any way to bridge the current antenna mount without opening up the stereo to bypass the antenna circuit?
mcovingt@athena.cs.uga.edu (Michael A. Covington) (04/04/91)
If your FM antenna is a whip, and is 30 inches long and is vertical,
your reception is already about as good as it can be in your location.
There are two kinds of after-market antennas: those with a 75-ohm
coaxial cable, and those with 300-ohm twinlead.
To connect a 75-ohm coaxial one, simply collapse the whip antenna to
minimum size. Then connect the cable as follows:
--- inner conductor to the whip;
--- outer conductor (shield) to system ground, i.e., the outer ring
of the headphone connector or any audio connector that's convenient.
To connect a 300-ohm twinlead antenna, use a balun (transformer) to convert
its output to 75 ohm coaxial. (Exactly like the little transformers used
on cable TV connections, but backward.)
If you want better FM reception, the main thing you need is *height*.
Propagation is line-of-sight and raising the antenna even a few feet
can make a big difference.
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Michael A. Covington | Artificial Intelligence Programs
The University of Georgia | Athens, GA 30602 U.S.A.
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