long dipole vs trap dipole

long dipole vs trap dipole

Post by Rudy Marcellett » Fri, 04 May 2001 04:52:06

After reading the posts on the trap dipole--I started thinking--which IS the
better antenna:  Ladder line fed dipole cut for 160 meters used with a tuner
on all bands, versus a dipole with traps for 20, 40, 80 (for example, B&W
AS-160) and fed with RG-8 type coax.  I have both.  The Trap antenna is
mounted inverted V with apex about 48 feet and wires going NE/SW.  Ends are
only about 12 feet off the ground.  The other antenna has its apex at about
90 feet with one end at about 45 feet and the other at about 30 feet, with
the wires going SE/NW.  9 times out of 10 I will get the better signal
report and hear best on the ladder line fed dipole, but I think this is
simply because it is higher up and there is more wire up there.  The wire
antenna was a lot easier to put up, easier to take down and store, and there
was NO tuning or fiddling with t*** wire lengths.  Heck of a lot lighter
also.  Obviously you need a tuner with the ladder line antenna.  If they
were both mounted at the same height and configuration and measured, which
one would would out perform the other?
 
 
 

long dipole vs trap dipole

Post by W6RCecil » Fri, 04 May 2001 05:13:03



> Obviously you need a tuner with the ladder line antenna.  If they
> were both mounted at the same height and configuration and measured, which
> one would would out perform the other?

If certain precautions are taken, IMO, there is no substitute for being
able to do the tuning of the antenna system at same place as the operator.
Given a near-lossless transmission line, a non-resonant antenna length
will radiate virtually just as well as a resonant antenna length.
--
http://www.mindspring.com/~w6rca

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long dipole vs trap dipole

Post by Ken Bjorklu » Tue, 08 May 2001 19:53:34

>Subject: Re: long dipole vs trap dipole

>Date: 5/2/01 1:13 PM Pacific Daylight Time


>> Obviously you need a tuner with the ladder line antenna.  If they
>> were both mounted at the same height and configuration and measured, which
>> one would would out perform the other?

>If certain precautions are taken, IMO, there is no substitute for being
>able to do the tuning of the antenna system at same place as the operator.
>Given a near-lossless transmission line, a non-resonant antenna length
>will radiate virtually just as well as a resonant antenna length.

One must not forget the drastic changes in radiation pattern a long dipole, say
160 meter half wave, exhibits as it is operated above its cut frequency. This
antenna has a pattern similar to a many petalled flower when operated at 20
meters and above. This may be good and it can also be bad. A trap dipole, if
designed properly, should produce a bi-directional pattern on each of its
operating bands.

73
Ken
KK4BH