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Old June 3rd 06, 10:55 AM posted to rec.radio.amateur.homebrew
 
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Default Want To Build a Directional, Amplified Medium Wave Receiving Antenna - Where To Start?


Dan Winker wrote:
A huge loop seems like overkill and not directional anyway. I don't think I have room for a dipole (is that 318 ft?). What I'm inventing in my own head is a loop with lots of turns. I think they used them in the old days. They were like a coil of wire mounted on a 2 ft by 3 ft board. Would (1005/1.47 = 684) feet of wire in a 3 ft diameter coil form some kind of ghost show antenna (for KLBP)?


I'm quite capable of reading parts of the ARRL handbook, ordering stuff from Digi-Key, and soldering. Where should I start? What about making it amplified?

BTW, here's my crystal radio that currently doesn't do anything because it doesn't have an antenna. http://www.visi.com/~dwinker/ddd_xtal_radio/ (It is finished now. I gotta get a final picture up now that I've posted this). It'd be cool if I could make that work again. I wouldn't feel to bad if it took an amplified antenna to make it work.


Dan,

You might read this area of my website:

http://www.w8ji.com/receiving.htm

If you have a weak staion with a strong co-channel staion causing
problems, you need a directional antenna with a fairly wide and stable
null. You won't find that in a single loop. You won't get much useful
directivity or gain from any single element antenna, and a loop will be
the same with 10 turns or one turn as long as you resonante it. It is
the SIZE and balance that mainly affects sensitivity, pattern, or
directivity.

Still, we can sometimes find a small antenna that just seems to work
better than we might expect so experimenting doesn't hurt. But as a
general rule you might have to use two elements phased to get a useful
pattern

73 Tom