Thread: Need a balun?
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Old July 27th 15, 09:15 PM posted to rec.radio.amateur.antenna
Ralph Mowery Ralph Mowery is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 702
Default Need a balun?


"Dave Platt" wrote in message
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- If the feedline is long enough, and/or far enough away from an
even-halfwave length, then the impedance along the outside of the
coax will be high and/or reactive enough to result in a low level
of current flow. Under these conditions a balun may not make any
meaningful difference.

A lot of people run "half-wave" center-fed dipoles without baluns, and
are perfectly happy with the result.


I am one of those people. I have an 80 meter dipole and do not use a balun
on it. It is about 50 feet high and 100 feet of coax to the shack. Also on
it I have added two other dipoles for the 18 and 24 MHz bands. When it
comes into the shack there is a coax switch for several antennas and a wire
going to a ground rod and it is also tied into the house ground. Seems to
work ok running 1200 watts without problems on 80 meters. I only run 100
watts on the other 2 bands as the amp is not set up for them. I have used
the amp aroun 500 watts a couple of times for short contacts on the other
bands.

The 80 meter dipole compairs fine to an off center fed antenna that is about
10 feet higher and at right angles to it. The OCF has a 4:1 voltage balun
at the feed point and a bead choke about 20 feet down the coax and 80 more
feet to the coax switch.

I think both antennas are too low to the ground to be very directional.
They are supported on the ends so are in a V or almost flat top.