I like using plug-together sections. Using 2 x 22ft sections on one side
and one 22ft section on the other makes a nice OCF dipole that is close to
50ohm on 40, 20 and 10 with a 4:1 balun. Adjust middle and end height to a
good match without a tuner. Other 1/3 2/3 arrangements can be made using
plug-together sections to cover more bands without switches or tuner. Do
the same for the vertical version.
Even good quality tuners work better with loads that are closer to 50ohm and
the OCF with balun/choke makes it easy.
David
G3UNA
----- Original Message -----
From: "Don Wilhelm" <w3...@embarqmail.com>
To: <elecraft@mailman.qth.net>
Sent: Tuesday, January 29, 2013 2:06 PM
Subject: Re: [Elecraft] Best Portable Antenna
All,
OK, a great discussion, so I thought I would share the antenna I like to
use for portable. It is basicly a 44 foot doublet fed with 300 ohm
ladderline (32 feet long with an additional 10 foot section that I can
add). I couple that with my Jacktite 32 foot telescoping pole. Things
fasten together with Anderson Power Pole connectors. In addition, I carry
2 additional 22 foot lengths of wire.
I strap the pole to anything vertical, I have the heavy duty pole, so if I
can find a support that is 3 feet high or more, there is no need for
additional guying.
That antenna can deploy in a variety of ways. If an additional support is
available, I use it as a horizontal dipole. In situations where there are
low bushes around, it goes up as an inverted vee - just tie the center
insulator to the top of the pole and push it up - tie off the ends to
whatever supports are available. If I want to operate 80 meters or want
better efficiency on 40, the two 22 foot wires are added making it an 88
foot dipole.
If space is limited, or I want a vertical, one end of the antenna is
fastened to the top of the pole, and the other side of the antenna acts as
a bent radial (the feedpoint is 10 feet above ground). The other two 22
foot wires can serve as additional radials. Support the feedline by
whatever means available.
I use a switchable 1:1/4:1 balun at the end of the feedline and a short
length of coax to the rig.
So, you don't have to be slaved to any one type of antenna. Sometimes
'best' is dictated by the physical surroundings. If you want to work
locals, use the inverted vee or dipole, but if you are trying for
something more distant, use the vertical configuration.
Other than the Jacktite pole, the antenna is inexpensive, but there is no
commercial offering, you have to build it yourself.
The 'magic' of the 44 foot length is that the antenna radiates broadside
to the wire with no lobes until you get above 10 meters, with the 88 foot
length, lobes will be present above 20 meters.
73,
Don W3FPR
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