RE: [amsat-bb] GRRRRRRRRRRR!

["Howard Long" <howard@xxxxxxxxxxxxxx>]

Hello Fred

> The way Howard has his antennas is like shown in the ARRL Sat book.. this
> has fallen out of favor somewhat as the polarization will always come out
> elliptical rather than circular as the elements are not in exactly the
same
> plane.

Mmm... I've had to think about that one. If the antennas are pointing
straight at the sat, and the sat's pointing straight at your station then
all should be hunky dory. Of course, that never happens...

Here's where I think you're coming from (and I think you're absolutely
right)...

At 70cm with a 2m separation you're in grave danger of having to switch
polarizations on occasion a few times during a pass - which I've found you
have to do. That's not because of the ground station's off pointing: that's
the off pointing of the satellite and the phase difference at the separated
antennas.

So if you're going to separate the antennas I'd guess that having the
polarization switching's even more important. I have to be honest and say
that although I marked the switch RHCP, LHCP, horizontal and vertical, I
just choose whichever one gives the best result.

I have tried putting all the 2m elements of an Arrow on one boom, and all
the 70cm elements on the other boom, but I could never get the antenna to
tune that way. That was originally the preferred route, believe me!

I think though that the operating results speak for themselves to a great
extent.

Another option is to build Jery K5OE's cross yagi antennas of course, which
are not much bigger than Arrows and much much cheaper.

Since moving to antennas with all elements of the same band on the same boom
I've found far less reason, or benefit, from switching polarizations during
a pass.

73 Howard G6LVB

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