Hi Tom,
Thanks for your comments & I agree with you that all antennas are certainly
compromises of various parameters and no one antenna can do it all -
certainly one of the mantras of our hobby. I response to Tony's question I
was wanting to describe in some detail how the total sum amount of
directional coverage gets progressively worse as more "holes" in the
coverage develop with higher order length antennas.
>From 2004-2006 I used nothing but wire antennas (five of them that I
remember) and several that were fed with ladder line worked very well. The
shorter ones could easily cover 14-28 mhz and the longer ones could
reasonably cover one band below and above the fundamental frequency within
the limitations previously described. I did not experience the noise issues
that one of the other posters brought up - I suspect that may have a lot to
do with the installation (how cleanly one can route the lines out of the
shack) and the amount of local noise sources present in the near field of
the station.
73
Matt
KM5VI
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Tom
Osborne
Sent: Monday, May 05, 2014 11:18 AM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] In Shack Tuner Vs. Remote Tuner for Multi-Band
Antennas
Hi Matt
Isn't that effect present in any antenna (except maybe a vertical)?
If you put up a dipole, there are 2 main lobes and off the ends is a big
null. I just don't see any antenna that is going to be perfect. In order
to cover many directions with dipoles or fan dipoles, you are going to have
to put up 2 for each band at right angles to each other.
If I want an antenna to cover NE/SW, a dipole will do that, but will have
nulls NW/SE, (assuming it is high enough to have lobes and not shooting
straight up) so now I have to put up 2 antennas.
I still can't see any disadvantage to an 80 meter (or longer) dipole fed
with ladder or window line, except maybe a bit more noise on the ladder
line. Every antenna has advantages and disadvantages - you just have to
weigh them out.
I have an antenna that is about 190 feet long, up in a tree about 90 feet
fed with window line. I also have an 80 meter elevated vertical with the
base at 6 feet with 5 radials. For 40 I have a full sized delta loop in a
tree up about 70 feet. The center fed antenna works better in most cases
than both of those antennas doing an A/B test, and I can use it on 160, 80
and 40. But, I am not using a tuner with a funky built-in balun to try and
match the antenna.
I just don't think there is one perfect solution for just 1 antenna. 73 Tom
W7WHY
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