Hi Bob,
Everyone has to weigh their operating against what the antenna
does. I'm not speaking of one antenna over another because I have
no preference, I don't use tribanders.
> Mike, at my previous house, I had a Mosley TA-33 @ 45'. I live in the
> black hole of Northern Indiana. After using it for 3 years, I replaced
> it with a C-3 @45' in 1997. I don't have any scientific figures for
> you, only a seat-of-the-pants guess. There was quite a bit of
That's a tough call, isn't it? The biggest improvement in propagation
above 20 meters occurred around that time. Change antennas now
on the downward slope (which is more gradual) and in three or four
years you might be saying "what the heck happened to my
antenna?".
I generally leave an antenna up for about a year and compare it, but
most of us do not have that luxury. So we just cross our fingers.
> difference. I play around in most of the contests, and it really had a
> bearing there. The F/B ratio was a little looser than the TA-33, but I
> heard stuff that I know I never heard before, and I was making fewer
> calls before being answered. I used the C-3 to take 1st place in
If F/B was less, and you were hearing more, the improvement
might have been because in contesting you generally don't want a
tight pattern.
In the 160 contests, even though I have directional antennas, we
spend 90% or more of the time on omni antennas.
Just to debunk a common myth, 8 db of gain does NOT mean 8 dB
improvement on receiving (as is often thought). The improvement
might be twenty dB, or minus 20 dB! Gain has little to do with
receiving abilities.
The important parameter is pattern, which can be excellent even
with negative gain antennas. For receiving signals in a given
direction you want the cleanest and deepest nulls everywhere
except in the direction of the desired signal. My best receiving
antennas all have negative gain, and that would carry through to
frequencies somewhere above 30 MHz.
If you are trying to work signals everywhere, you really don't want a
clean pattern with deep nulls. If you are digging for weak stuff in
specific directions, you do. But keep in mind the difference is only
in pattern shape, regardless of actual gain.
I hope this doesn't confuse the discussion, but I think it is
important to remember pattern for receive, gain for transmit.
73, Tom W8JI
w8ji@contesting.com
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