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Old May 24th 10, 04:00 PM posted to rec.radio.shortwave
Mark S. Holden Mark S. Holden is offline
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First recorded activity by RadioBanter: Jun 2006
Posts: 32
Default Backyard antenna considered...

John Smith wrote:
I have a wood fence around my back yard. Across the back stretch is 79 feet.
The fence extends 76 feet from there along each side of my house which is 50
feet wide, leaving around 14 feet on each side of the house. The back of the
house to the fence is 37 feet . The eve of my two story house is, if I
remember right, about 23 feet above the ground. I want to erect a random
wire antenna of insulated 12 gauge wire from one corner of the fence in the
back, lead it up to the middle of the house to an insulator, then back down
to the other corner of the fence, where the feedpoint will connect at the
end. The back of my house faces due North. The antenna will be held about 8'
feet off the ground at the fence corners by schedule 40 PVC pipe. I want to
juse the feeline system as described by John Doty in this article:
http://www.hard-core-dx.com/nordicdx...eed/feed1.html
I have a Radio Shack DX-398 equivalent of the Sangean ATS-909. I was
thinking the two ground rods will be set in a hole 1 foot in diameter
filled with a Bentonite slurry. I was wondering if the random wire folded
into such an inverted V facing due North will have good reception qualities.
The previous residence I erected an inverted L random wire antenna and
received excellent results, but seemed very directional. I am hoping the
inverted V shape will help diversify the direction of reception somewhat at
this house. What do you all think?



I have a 65' random wire located about 225 feet from my house with a 9:1
matching transformer at the antenna end, and roughly 300 feet of coax
running underground (in plastic conduit) between the antenna and the
house and then up and over across my attic before coming down the wall
where my radio is. There's a ground at the matching transformer, and
one at the house. I've got ferrites at each end too.

It's a wonderful antenna. My noise floor is incredibly low.

A concern I have with the antenna you're proposing is you're bringing
the antenna back to the house - where all the electrical noise you're
looking to avoid is located.

Your radio really doesn't need a big antenna. Design yours so you keep
the antenna as far from your house (and your neighbors homes) as
possible. 15-20 feet is probably plenty for that radio.

RFI strength goes down by a square of the distance. Put your antenna
twice as far away and you get 1/4 of the noise signal. Three times as
far away and you get 1/9 of the noise signal.

Something to consider is if you're even thinking about getting your ham
ticket some day, it's worth spending the money up front to use low loss
coax or heliax. My antenna is useless for tx, and digging up all that
pipe to replace my coax just isn't an attractive option.