[TowerTalk] Re: Can takeoff angle be too low?

[Pete Smith]

Wait a second....

N6BV's original data made certain assumptions about the antenna on either
end of the path.  In about October 98, he revised the data, based on
assuming isotropic antennas at each end of the path.  These tended in
general to give more weight to lower-angle modes.  In both cases, my
understanding is that only the best mode was counted, even in cases where
there were 4 or 5 different ones, some within a few dB of the best one.

If you assume low dipoles and/or tribanders on the other end of a W1-4/EU
path, then a high antenna may have a null right where the European antenna
is concentrating its energy.  There will be times when (with these antennas
) signal strength will be significantly better at a higher angle (with more
hops) than at a lower one.  The result could very well be a perceived (and
real) advantage to the lower antenna at those times.

Try to apply the same principle in W9 or W5 and it probably doesn't prove
out, because those high angle modes are not present for much of the time,
and when they are the signal level is less.

Because their vertical lobes are wider, stacks probably average better than
a single yagi, more of the time. 

What am I saying?  Everyone is right, depending on his situation.  There is
no one right answer.  There's no substitute for individual analysis, taking
your terrain and propagation into consideration.

73, Pete N4ZR

Contesting is ... Extreme Radio

The World Contest Station Database 
is back up and running at
http://www.qsl.net/n4zr 



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