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@mta.ca wrote:
Quoting Howard Long howard@howardlong.com:
[snip]
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 _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb