While we are discussing 80m antennas, can someone shed some light on the
radiation pattern of the SteppIR dipole option for the larger DB36 and DB42
models?
Is the maximum radiation towards the front and back of the antenna elements, or
off the left and right sides of the boom?
Also, what would you consider this design? Some sort of "H" dipole?
Anyone know of any good write ups on this sort of "H" antenna design (the 80m
portion, obviously) on the web?
Finally, has anyone compared this to an 80m inverted V at similar heights?
I have the DB36 with the dipole option at 91 ft, and an inverted V 80m dipole
with the feed point/ apex just below it at 89 feet. The end of the two legs of
the inverted v are at approximately 45ft above ground.
I also have legs for 160m fed off the same feed point, which sit/hang 2 or 3
feet above the 80m legs. They are tied to the same end posts as the 80m legs.
I just leave the ropes for the 80 m legs a little bit looser so they sag down
below the 160 m legs by a few feet on the way down from the tower.
Unfortunately I have no trees on the property, so the only tie offs are two
posts in the far corners of my property.
I am sure there is some severe interaction, so it really is hard for me to tell
which one works better sometimes.
My experience with both seems to show that the StrppIR "H" dipole is a little
better for the long haul stuff into Europe, while the inverted V is much better
(by 10db) for the close in (200-300 mile) and rag chew type contacts on 80 m.
On a related note, I believe I am having some noticeable interaction with these
inverted V's when I have the SteppIR on 40 m. As a non-scientific comparison,
my buddy (N2II) up the road a few miles with only a two element 24ft boom
linear loaded 40m yagi at the same 89ft height seems to do equally as good, if
not slightly better, as I do with the three element 36ft boom SteppIR on 40 m.
I have no experience with modeling, unfortunately. My area of expertise in the
hobby is radio and amplifier repair. FWIW, I am willing to trade repair
services for modeling services if anyone is ever interested in modeling my
antenna set up.
Eric
K2CB
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