Topband: 160M 8 Circle Array for transmit
Richard (Rick) Karlquist
richard at karlquist.com
Fri Mar 4 19:16:51 EST 2016
On 3/4/2016 1:51 PM, Dan Maguire via Topband wrote:
> There are some fairly detailed 8-circle modeling studies in the last section on this page:
> Lots of illustrations and several url links for more info.
> Dan, AC6LA
> Topband Reflector Archives - http://www.contesting.com/_topband
I looked at that page. That configuration is even larger than
what I decided on. More acreage to get a little more gain at
the expense of increased sidelobes. That was what made me look
at a smaller circle (although I have space for the larger circle).
I also looked at the Hi-Z array. It is much smaller, but has
good gain and low sidelobes. The disadvantage is that it is
relatively narrow band and very critical. Also, you have to
feed all 8 antennas at once with 3 different phases. I
suspect it would be difficult to make a transmit version.
The BSEF array I am using is very broadband and not critical,
and you only feed 4 antennas at a time. Easy to feed as a
transmit array as well. If you have the space for it, it
makes a lot of sense. The 290 foot circle I am using may have
already been written up somewhere before. It seems "obvious"
to me: an octagon 1/2 wavelength across the flats.
I didn't read all the references.
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