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#160032 05/01/05 05:39 PM
Joined: Feb 2005
Posts: 693
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For radio, and especially AM radio, the most important thing is the voltage across the tuner input. For LF signals, that's best acheived with a long-wire antenna and a good ground.

Since the radio has external antenna terminals (which probably feed a coil on the radio's internal loopstick antenna), try connecting a piece of wire to one, and a good ground to the other.

The best extarnal (active and passive) AM antennas are probably those sold by the C. Crane Co.


Larry Fine
Fine Electric Co.
fineelectricco.com
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#160033 05/04/05 05:44 PM
Joined: Aug 2001
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TV sets that use antennae, to recieve a signal now are still 300 ohms but we use a 75 ohm coaxial cable to feed the TV Set.
Don't forget that there's a big difference in characteristic impedance between a regular open dipole and a folded dipole, the latter being common on TV antennas.

The addition of directors and a reflector also has a great effect on the impedance.

#160034 05/04/05 08:33 PM
Joined: Jul 2002
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Don't forget that there's a big difference in characteristic impedance between a regular open dipole and a folded dipole, the latter being common on TV antennas.

The addition of directors and a reflector also has a great effect on the impedance.
Ahh good point Paul, I think I might have actually been comparing apples to banana's there.

#160035 05/08/05 10:14 AM
Joined: Jul 2002
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Jps,
At the end of the day, your bookshelf stereo isn't going to have the capability of a really good reciever no matter what you put on the end of it.
Generally they are made to a price and the "front-end" of the reciever often generates more noise than the antenna can provide, let alone immunity from other nearby noise sources.
I have a problem at the moment with my 2m (144MHz) transciever knocking out all of the AM Broadcast band on my neighbours radio, its not harmonic or sub-harmonic, it's just the fact that the RF Amp on thier radio was so poorly designed.
I can listen to mine no worries at all.

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