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Old 18-10-2011, 15:47   #1
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Best AM Antenna ?

What is the best long distance AM antenna.I have a vhf splitter ,not great on AM.
Ian.
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Old 18-10-2011, 16:19   #2
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Re: Best AM antenna ?

After trying several ideas, I found by far the best option for our boat was running RG 59 coax all the way forward, and attaching the inner wire to the forestay chainplate.
The mast has a dynaplate, so it amounts to a huge loop antenna.
AM and FM all work great.
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Old 18-10-2011, 18:42   #3
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Re: Best AM Antenna ?

Fo receiving AM, you don't need coax. Run the longest wire you can as most AM broadcast is in the low end of the HF spectrum, i.e., long wavelength. Connecting it to anything attached to the boat's ground can create susceptability to lots of conducted noise.
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Old 18-10-2011, 21:34   #4
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Re: Best AM Antenna ?

Quote:
Originally Posted by S/V Illusion View Post
Fo receiving AM, you don't need coax. Run the longest wire you can as most AM broadcast is in the low end of the HF spectrum, i.e., long wavelength. Connecting it to anything attached to the boat's ground can create susceptability to lots of conducted noise.
The reason I ran coax was to get away from the RFI of various digital goodies in the area of the radio.

In urban areas, it wasn't a problem but when you're out in the islands, you need a lower noise floor.

Thus, the headstay, and no noise (at least on my boat).

Further, almost every AM/FM radio I've ever repaired (in a previous life I did exactly that for 30 years) there's no DC coupling from the center lead of the coax to the chassis.
There is at least one capacitor before it goes to the first stage.

I did not connect the coax shield to anything at the headstay location, only at the radio's antenna plug.
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