Bill,
None of that is really a problem to me.I have multi points to which I
can feed for different patterns depending on the time of the day as
well as option of tilting the array. If I don't get my elmer I will
assume he is not on the air and yes it is twenty meters and I am
located in the couintryside that I understand is the highest between
Chicago and New Orleans and since this is the bread basket of the U.S
the ground loam is excellent. I use 7/8 andrews plus a long length
underground and the tower is hinged in two places
as well as another one for array tilting. I have power gain over a yagi
but I was just curious as to how much more radiation energy was
available to ensnare which Is why I referred to array volume since gain
is really dependant on half power beam width required or one can live
with I once had a 80 foot yagi and with the looseness in my prop pitch
rotor combined with the narrow beam one was never sure if one was
really taking advantage oif gain available. Pretty simple question for
those who know the answer after all you start off with 3 db gain in two
different directions thereffore it would seem to me that a yagi was
only 50% efficient but people are quarrelling about every thing except
the posed question to excuse them selves from real thought. Reg would
have come up with the solution after a bottle of wine after noticing
the english provided by the cue
Regards
Art

wrote:
art KB9MZ wrote:

Thus my major lobe needs to be robust between about 10 degtrees and 4
degrees to ensnare most of the communication.

I don't recall you stated which band but I'll assume 20 meters.
Assuming flat terrain (for your Indiana QTH), a single Yagi at 120'
(your maximum possible) would cover these angles best. 140' (or 2
wavelengths high if it is not 20m) would be the optimum heightl to
center your main lobe at 7 degrees.

Two stacked Yagis at 60' and 120' would be better than a single one at
120' or 140' for 4-10 degrees, but obviously this means more work and
expense.

If your terrain is not relatively flat, and if you are lucky to be on a
hill with a gentle slope in the direction of England, the optimum
height will be much less. However you would need to model this using
HFTA in the most recent Antenna Handbook or YT in older editions.

73, Bill W4ZV