TT:
This to some degree echoes previous comments, adding personal bias:
1) You can't control trees. Use 'em to hold up antennas, or ignore
'em, so long
as they don't snag your beam. Tree absorption is a negligible
factor at HF.
Don't even think about it.
2) height above ground is everything, in determining takeoff
angle. Somebody said
'use HFTA'. They're right, partly. (see rules 6 and 8) 55' is
better than 70', on some
frequencies. 70 is better on others. See HFTA for details.
3) Quads are not better than equivalent height and size yagis,
although you have to consider the
loop gain in the performance. They hold no magic, but surely
have compared well, historically,
to lossy-trapped tribanders. 2 el quad will often trump a 3 el
trapped yagi, at the same height.
4) An equivalent boom length LPDA will equal a 3 el trapped yagi, at
the same height. Trap losses
will kill you.
5) And my personal favorite: The SteppIR. My 3 el steppIR was
the best single antenna I've had
up in 45 years of hamming. The Tennadyne T10 LPDA and KLM KT34A
were close, on some frequencies.
6) Repeating 2, Height Matters. My SteppIR was at 90'. The
hill in the direction of EU was 150',
and only maybe 200' from the tower. It didn't matter that I was at
-60', I still broke EU pileups readily.
But SW thru NW, the ground sloped gradually down for several miles.
I was a killer into the pacific!
7) My 160m halfwave was at 120' laying on trees. The Hill behind
the house, as above, was at 150.
Made absolutely no difference. "Earth" at 300 Terahertz (what you
see) is NOT what your
RF at 1.8MHz sees! My 160m GP was literally laying IN a 140' high
pine tree. Didn't matter.
8) And my final comment... an antenna in the air will outperform a
model, every time.
Just put the damned thing up!
N2EA
Jim Jarvis, MBA
President-Executive Coach
The Morse Group, LLC
732 548 5573 office
908 410 9130 cell
People-Process-Strategy
Achieving Results in a Changing World
www.themorsegroup.biz
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