[amsat-bb] Re: Crossbooms ... my pennyworth.
n4qwf1 at gmail.com
Wed Jan 10 16:39:05 PST 2007
This has been discussed many times over the years and I still don't
see why. I have been using a 10 piece of thick wall metal pipe since
1992 and never seen any problem. I have my 2 meter and 70 cm cross
yagis on the ends so the pipe passes only heavy way and it works
great. Since I worked AO-10 and AO-13 and later AO-40 at 30,000km I
assume the metal boom is working just fine. I used the same setup at
K4CQ for fieldday this past summer and came in 3rd over all. I guess
folks should use what they are comfortable with. My point is it ain't
that big a deal.
That is my 2 cent worth.
73's << John
On 1/10/07, Bruce Robertson <broberts at mta.ca> wrote:
> Quoting Howard Long <howard at howardlong.com>:
> > could ever get a great match, particularly on 70cm. So I resorted to
> > making
> > circular polarisation work with the 2m and 70cm planes separated, and
> > remote
> > preamps and remote polarisation switches.
> > This worked _very_ well, and the gain you achieve by being able to
> > manually
> > 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
> > very
> > 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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