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Hello:
Do listening only. Presntly using a random length wire strung around the 4 sides of my attic (probably about 40 ft x 25 ft x 40 ft x 25 ft; resultant loop left open at end) Works fairly well, but would like to try and do better. Might bite the bullet this spring, and try putting something outside. Whatever I try, I want it to be omni-directional, and be fairly broadband in freq. coverage; say from 500 KHz to 30 MHz. No Tower. a. For something relatively straightforward, what type or brand would you suggest ? Worth doing over what I now use indoors ? b. Any probable advantage to taking the most simple approach, and ust stringing a 150 foot straight wire outside compared to what I now have in the attic, assuming same height. c. regarding nearby lightning strikes and resultant voltage surges picked up by the indoor antenna wi does the house roof off any meaningful protection (when dry) compared to a wire strung outside? BTW: For a straight 150 foot wire, at a height of about 25 feet, is it most sensitive perpendicular to the wire axis, or along it ? How does the answer depend on received freq. ? Much thanks, Bob |
#2
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On Mon, 5 Apr 2004 14:11:59 -0400, "Robert11"
wrote: Hello: Do listening only. Presntly using a random length wire strung around the 4 sides of my attic (probably about 40 ft x 25 ft x 40 ft x 25 ft; resultant loop left open at end) Works fairly well, but would like to try and do better. Might bite the bullet this spring, and try putting something outside. Whatever I try, I want it to be omni-directional, and be fairly broadband in freq. coverage; say from 500 KHz to 30 MHz. Hi Bob, You fail to mention the quality of your receiver, I will proceed as if it were middle of the road ($200-$400). Your open loop should be coax fed with a choke at the feed point to reduce noise from the house coupling in (unless there are noisy components in the attic). At the other end of the coax, back at the receiver, you should be using a tuner to perform matching to DX and rejection of strong AM stations that can seriously de-sensitize you (this is the hidden DX killer). Connect to a suitable ground. This sometimes does wonders for sensitivity. It also sometimes introduces ground loop problems (solving those problems is worth while to keep the ground). You already have "enough" wire. Your future goals should be to move it away from the house if you suffer noise. You would also stand to gain if you can elevate it higher. Either way, more wire is unlikely to bring any fantastic return. This has exceptions, of course, if you want to try Rhombics, or Beverage Antennas (these require serious real estate for HF however). 73's Richard Clark, KB7QHC |
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