Original article from: Wayne Sarosi 
 Reposted by Rob Dennis,Moderator HAM_TECH,for use of the FIDO HAM_TECH echo.
  THIS POST/SERIES NOT TO BE USED IN ANY CDROM COMPILATIONS FOR COMMERCIAL
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SUBJECT:  Wire antennas - part one
 Dollar for dollar,the wire antenna is an Amateur Radio Operators (AROs) best
bet when it comes to inexpensive antennas. In the lower bands,160,80,and 40m,
the wire antenna is nearly the only means for most AROs to work those bands.
 Wire antennas perform from great to poor depending on many factors even when
the antenna is cut for the frequency desired.
 I'll discuss some of my findings with wire antennas in this ten part series.
 Since most of the wire antennas are published in numerous antenna books,the
specifics of most wire antennas will be left to the reader to investigate for
the band they wish to operate in.
 Instead,I will discuss some helpful hints,findings,and misgivings about wire
antennas that the ARO can use in overcoming the difficulties encountered with
their first wire antennas and some that the old pros may find usefull.
 I'll be discussing advantages / disadvantages of wire antennas on different
bands,wire diameter,ground height,matching,multi-band wire antennas,and a few
other odds and ends.
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 First,let's look at the capture area of a wire antenna cut as a dipole.
 We can examine this at 10m for ease of calculations and understanding.
 Many hams use a #12 or #10 wire when constructing their wire antennas.
 It's cheap and easy to obtain.
 Some wire antennas come as kits and use stranded wire verses solid 
onductors
many hams use in their home construction. Looking at the diameter of the 
ire,
whether strained or not,it can be easily seen that a dipole made from 
luminum
tubing has a greater capture area,without picking up a calculator to find out
the difference.
 Larger diameter elements produce greater bandwidths,thus a wire dipole on 
0m
would have a limited bandwidth compared to it's aluminum tubing counterpart.
 How does one overcome this?
 Through trial and error,and a tight budget when I first got into Ham radio,I
found that cutting the wire slightly shorter than the designed frequency and
adding some tubing to the end of the dipole,I was able to expand the 
andwidth
of the wire antenna up to three times the orignal value.
 It doesn't take much tubing or a large diameter to accomplish this.
 I used two of these units (of course,one on each end).
 There are two parts to the extention. Use a 12-in x 1/2-in diameter tube 
ith
an 8-in x 3/8-in tube telescoping inside the former.
 By placing a vertical cut into the 12-in section,a clamp can be used to lock
the two tubes together. Now you have tunable end pieces.
 Run the support rope through the tubing and attach to the wire then secure
the wire to the 1/2-in end of the tubing. A good electrical contact is a 
ust.
 The rope will support the tunable end piece.
 The end pieces are also much greater in diameter than the wire,adding to the
capture area. Also they provide a tunable method for zeroing the dipole to 
he
frequency desired or changing the frequency of the dipole later.
 At 10m,I would recommend an aluminum tubing dipole and save this technique
for the 30m and below antennas.
 For the lower frequency wire dipoles and inverted vees,the tubing can be 
ade
much longer for better results.
 There is a fine line between weight and performance that needs to looked 
nto
when using this method and it's a function of the antenna support and support
lines.
 I stumbled across this technique while putting around with a 40m inverted V.
 I just could not get the bandwidth and SWR right. It was either too high for
the resonant frequency or too low no matter what the calculator thought.
 The SWR was 2:1 and I wanted an antenna that did not require a tuner for my
solid state radio. I grew tired of soldering and cutting wire and decided to
add the tubing extenders. Not only did I get the Inverted Vee on target,7.15
MHz,but I covered the entire 40m band and the MARS frequency I was required 
o
attend on. The SWR was below 1.5:1 across the entire band also!  :-)
 It worked so well I decided to bring it to field day,1991.
 The antenna worked very well and without a tuner.
-WS
--- GoldED 2.42.G1219
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