Wondering what experience there is for 3L Bruce arrays and if a
reflector has been tried? It looks like a good "bang for the buck" way
to get some low angle gain. My interest is to 80m to improve low angle
(5-20deg) versus a 86' rotatable dipole (Tornado tuned
redesigned/rebuilt EF180C) at 100'. The goal is a better signal to EU
from Seattle, a tough path vs the W1's. I have some free antenna
supports in the form of 100' hemlocks and cedars with the right
orientation and the highest support rope can be about 90' agl.
I've run a bunch of EZNEC sims which show 18deg gain improves by 1.1db
and at 10deg by 3.6db for the 3L Bruce with its top at 80'. Helpful, but
not dramatic. Very wet winter earth here is a bit better than average,
I use 0.01ms for ground conductivity.
I think it is mechanically feasible to add a close spaced passive
reflector, 25' separation. Then the sim'd gain improvement vs dipole is
4.1db at 18deg and 6.9db at 10 deg and 10.1db at 5deg (my QTH has a
good EU HFTA) over the dipole. That is really getting interesting, but
I am wondering how much to trust EZNEC with such close spacing ~0.1wl.
I have no place to put radials for a 80m 4 sq transmit antenna, and the
cost would be a LOT more if I did. I've modeled phased delta loops hung
from a 90' tower, but the reported tuning difficulties and sim'd tower
interactions are a big concern plus poorer low angle gain.
Inputs and better alternatives appreciated.
Grant KZ1W
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Topband Reflector
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