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Subject: Re: Another (FM) antenna question
References: <email@example.com> <3DEDA415.65EF53A1@one.home> <3DF5CA46.794515CF@one.home>
X-Newsreader: Forte Agent 1.92/32.572
Date: Tue, 10 Dec 2002 12:28:05 -0500
NNTP-Posting-Date: Tue, 10 Dec 2002 12:28:12 EST
Organization: Bell Sympatico
On Tue, 10 Dec 2002 05:04:38 -0600, Bob wrote:
>> I don't get it .
>> Are the two stations in line with your location ?
>The stronger signal is based about 20 miles due north of my
>location, the weaker one that I want is about 40 miles
>> If they are't and if the signal from the wanted station is sufficient
>> , you may get better results with a simple loop antenna .
>So it sounds like a basic UHF-TV antenna... I have one that's
>sort of bow-tie shaped. I'll hook it up (300ohm input) and line
>it up with downtown Dallas (north-south orientation). Sounds too
The bow-tie antenna that you have is designed to operate at higher
frequencies ( 470 to 890 MH) that the one you want to receive. The
design is correct but the size isn't. Consequently the results are
hard to predict.
You need a half-wave dipole.
The theoretical length of half wave length in inches is equal to
5609 divided by the frequency.
Multiply the result by 0.98 in order to compensate for velocity
The impedance of that dipole at that frequency is a bit less than 300
ohms (288) and you can use the 300 ohms line to connect to the 300
ohms input of your receiver.
You can built it by using copper, aluminum or even from a coat hanger
This is designed for your frequency and not exactly a typical FM
I predict that your chances for success are:
Your bow-tie antenna connected to the 300 ohms line 5%
A new dipole designed for the wanted frequency connected to the 300
ohms line 50%
As above but using a coaxial cable with one transformer at each end
If you move closer to the wanted station 99.9 %
If you can get the group
I can sketch some information and post it.
I have a friend that was receiving local tv stations by installing a
safety baby pin between the input terminal of the TV set.
I have another that receives local TV stations by exposing a couple of
feet of inner conductor of coaxial cable attached to a broom stick
I have received TV stations more than 3000 miles away with a rombic
Just try. All of this is assuming that you installing the antenna on
the roof and you don't have any spurious reflections from far or
distant buildings that can have a negative or , some times a positive
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