Hi Eric,
The dipole radiates at right angles to the boom. The end elements are for
loading. My MonstIR is at 83'. I also have an elevated wire 4-sq for 80M.
I live in upper NY state. From my QTH here is what I typically see:
For US, Canada and the Caribbean the MonstIR dipole is better.
To western EU, and Central America it swings back and forth which is
better.
On the longer haul stuff the 4-sq is always better. This is what I would
expect.
Tough trying to compare with your neighbor. Compare HFTA plots. There
shouldn't be too much difference between a 2-el and 3-el on 40M if the
heights and terrain are similar.
When I had my 80M 4-sq wires pulled in close to the top of the tower I
noticed interaction between the MonstIR and 4-sq. Took 'LPL's suggestion
and
made the 4-sq into inverted L's to get the wires farther away from the
tower. This helped F/B on the 4-sq. This also seemed to reduce
interaction.
And 40M SWR on the MonstIR would change from lowering and raising the 80M
4-sq wires until I pulled them away from the tower.
73,
N2TK, Tony
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
K2CB
Sent: Wednesday, October 14, 2015 9:20 PM
To: TowerTalk@contesting.com
Subject: [TowerTalk] SteppIR DB36/42 80m option
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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