"'Doc" wrote -
Dang Reg, how did you know what his backyard looks like??
'Doc
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Randy said -
" I need plans for a quick, easy to build, reasonable efficient
80m antenna. I have very limited space... "
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Dear Doc,
The key words in Randy's frantic appeal for help were QUICK, EASY,
REASONABLY EFFICIENT, 80m, LIMITED SPACE.
My response fits the bill exactly. It is the concise, accurate, reply which
I would have expected from your good, practical self.
The key words in my response were contained in the last sentence. For your
benefit I repeat -
"This will be the most efficient, all-band, all-direction, all-elevation
antenna which is possible in YOUR BACK YARD."
A coloured photograph with an ordinance survey map of his back yard, showing
his domestic and nearby buildings with trees and overhead power and phone
lines, with a cross to indicate the position of his shack window, are not
necessary to satisfactorily comply with Randy's brief, very common
requirements specification.
You may rest assured my suggestions apply to ANYBODY's small back yard. Read
them again.
The foregoing is for the benefit of novices and other lurkers. It should be
included in all editions of ARRL and RSGB publications. You just forgot to
include a smiley in your message. ;o) ;o)
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Incidentally, I am accustomed to changing my antennas fairly frequently.
Never had a permanent installation. My present recent antenna is an 18-gauge
enamelled wire which extends from the ground-floor kitchen window, up the
wall of the house, to a 10-feet mast affixed to the house chimney above the
apex of the roof. Overall height is about 40 feet. It is bottom tuned. There
are two ground radials. One radial consists of the domestic incoming metal
water pipe and is about 5 miles long. It is also connected to all the other
100 thousand water pipes in the area. The second radial is a fairly useless
12 feet long wire, connected along the soil surface to a 2-feet earth rod in
the garden soil. Resulting measured ground loss resistance is about 15 ohms
on the 80m band. So much for Marzipan the Magician's magic number of 120 as
plagiarised by the magazine guru's.
Athough I have considerably more real estate it is what I would refer to as
a very small backyard antenna. With 100 watts it will keep me happy on 160,
80, 40, 30 and 20m although, sooner or later, I MIGHT have a complaint from
the next door neighbour about TV interference on the higher frequencies. His
TV antenna coax down-lead is about 25 feet from my 'vertical' wire and he
has 3 TV receivers connected to his antenna, from one room to another via an
amateur electrician's coaxial ring main.
He will notify me of a problem by means of a heavy hammer on the adjoining
wall. He's that sort of person - considers himself to be the local Mafia
Godfather. He's 83 years of age, waiting for a hip operation, but claims to
have a step-son employed in a local firm of legal solicitors. However I have
reason to believe his step-son is just the inter-office message and
tea/coffee boy.
You fortunate, cheap gasoline, USA citizens, with vast antenna farms, don't
have the foggiest idea of what life is like for us mini-backyard denizens
inhabiting the rest of this over-populated world, wondering from where the
next scrap length of enamelled, annealed, copper magnet wire is coming from.
And if anybody thinks I'm just pulling your lazy legs - for once you are
right on the ball! ;o)
To estimate the L and C values of a home-brew tuner, suitable for any small
backyard vertical or inverted-L wire, download in a few seconds program
ENDFEED from website below and run immediately. A 3-weeks training course
not needed.
Regards from Reg, G4FGQ.
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For Free Radio Design Software,
made in the Black Country, near
the original Birmingham, England,
go to
http://www.g4fgq.com
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