[amsat-bb] Re: Crossbooms ... my pennyworth.
broberts at mta.ca
Wed Jan 10 04:38:36 PST 2007
Quoting Howard Long <howard at howardlong.com>:
> could ever get a great match, particularly on 70cm. So I resorted to
> circular polarisation work with the 2m and 70cm planes separated, and
> preamps and remote polarisation switches.
> This worked _very_ well, and the gain you achieve by being able to
> switch polarisation during a null when working LEO's cannot be over
> emphasised IMHO.
> One final point, radio amateurs have been doing antenna diversity for a
> long time.
> 73, Howard G6LVB
A contribution to the original discussion, plus a question:
I believe it was on this list that I read of an alternative to fiberglass
booms (of which there are none in my local sales area). My new 10' boom
comprises sched. 40 conduit with an snug-fitting 8' length of doweling
placed inside. Others have removed any 'play' between the doweling and the
conduit by spraying expanding foam inside the ends of the conduit. I
suppose one should cap the ends, too. The total cost of this for me was CAN
$20. The antennas, rotors and mast are on sawhorses now, but as far as I
can see the conduit-dowel boom has an appropriate stiffness.
Now my question:
Howard mentioned the much-documented advantages of polarization switching
for LEO satellite work. In this same context, is it worth the additional
work to include the remote logic required for V and H polarizations along
with RHCP and LHCP?
73, Bruce VE9QRP
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