The company is the Hy Power Antenna Company, and the antenna you are
refering to, I think, is the 3B4016L.
Isolation coils is a term invented by the company. I think what they
are doing is using a self resonant coil but not operating it at the self
resonant frequency. This requires a little explanation.
Looking at their coils, it is obvious that these are not high Q coils,
yet they claim they will handle full legal power. It's not likely you
can do that with low Q coils operating at their self resonant frequency
in a trap dipole. So they are operating them at a frequency removed
from the resonant point and adjusting the length of the wires to get the
resonant frequency back where they want. Traps in a trap dipole usually
operate at, or close to, the operating frequency, so they changed to
name to indicate the operation is a little different.
You can verify that conclusion if you know the length of the wires of
the dipole. If the length of the first section is NOT close to a half
wave on 40, then that would indicate the above is true. However if the
length of the first section IS close to a half wave on 40, then I would
be sceptical of their claim of handling 1500 watts.
As far as using 2 of these at 90 degrees, it's not likely to be of much
benefit except for very low angle signals. I wouldn't worry about a
balun making any difference in the pattern. You might find that a balun
reduces RFI or reduces received noise in some cases. Reduced received
noise is likely to only be noticed when you have very high noise on your
local ground and very low atmospheric noise on the band.
Hint: Don't depend on Eham reviews for judging antenna performance.
Jerry, K4SAV
Gary Slagel wrote:
>I'm looking at a 124' 160/80/40 multiband dipole from Hi Power antennas.
>Looks like a good product and reviews on eham are good. It uses isolation
>coils rather then traps. I'm not familiar with isolation coils and wonder if
>anyone has anything good or bad to say about these antennas. They obviously
>shorten the antenna up quite a bit. I've really got plenty of room for a full
>size trap dipole but haven't seen a full size that I liked real well and this
>antenna seemed good to me.
>
>Also, I'm planning on 2 antennas 90 degrees from each other. Should I make
>sure and get a balun on the thing so that I get the uniform pattern I'm
>expecting?
>
>Thanks for input!
>
>Gary Slagel/N0SXX
>Hot Springs, SD
>http://marina.fortunecity.com/sanpedro/351
>
>
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