Dave
No doubt a VHF tribander would be a great boon to VHF activity. As far as I
know only one was ever marketed. Ariane, the company that took over C3I when
Owen Wormser retired, had one on their books. It was about 15 feet long but
was not cheap - in the $300 range or maybe more - I don't remember. I know
who designed this one and his antennas work so I assume this one would have
worked. Unfortunately Ariane succumbed to high aluminum prices soon
afterward so we have no way of knowing.
Costs are not trivial because I'd guess it took some real engineering to
make all three section work independently and aluminum costs are
unpleasantly high.
The first homebrew HF tribander I ever saw was designed by my mentor, Len
Chertok W3GRF, and had 2 el on 20 3 el on 14 and 5 el on 10 in line. It was
around a 36 foot boom and was designed empircally there being no modeling
software available in the 1950's accesible by hams. It gave a very good
account of itself and I suspect that a VHF in-line tribander might work with
very little interaction between the bands. For the experimenters I would
start with WA5VJB 6 el cheap yagi on 2 and an 11 el cheap yagi on 432. That
makes a ~135 inch boom so far. At the rear end I would add a 2 el 6M moxxon
either homebrew or the one from Par Electronics if Dale still sells those.
Even buying the 6M portion I'd bet the antenna would cost less than $150.
If someone designs a tribander, models it and can describe it in 2 QST pages
I will offer to publish it in the World Above 50 MHz. The key of course is
something that is readily reproducible without tons of test equipment. That
is the primary virtue of the Cheap single band Yagis.
73 Gene W3ZZ
-----Original Message-----
From: David Pruett [mailto:k8cc@comcast.net]
Sent: Thursday, March 04, 2010 8:43 PM
Cc: VHF Contesting Reflector
Subject: Re: [VHFcontesting] Getting beginners interested in VHF Contesting
From the conversations I've had with non-VHFers, cost is a major issue to
getting on VHF/UHF. On HF you can toss a $5 dipole in a tree, feed it witn
junk coax and work a bunch of people on 80 and 40. As W3ZZ points out, that
doesn't work on VHF. Most decent VHF/UHF antennas are at least $100, and a
decent low lost feedline is at least $50, depending on how much length you
need. So $150 gets you ONE BAND worth of effective antenna. Joe706 needs
$450 worth of antennas (assuming he has a support for them) just to try
something he might not even enjoy doing. And if he want to get on a band
where he needs a transverter, that's another $400.
W3ZZ and I were discussing this at Dayton last year. I compared this
situation to the 50's, when Mosley or whomever commercialized the first
20-15-10 triband beam. Three bands from a single aerial and feedline,
reasonable cost and manageable size did a lot for activity on those bands.
Where would we be today in regards to contesting and DXing, without the
triband beam?
What we need is somebody to come up with a good 50-144-432 triband antenna
with a single feedline to go along with the IC-706s and the various Yaesu
FT-8x7s out there. If it were commercially available in the range of
$100-$200, that would be terrific. Icom and Yaesu have done a terrific job
with creating 50/144/432 rigs at reasonable cost, now if somebody could
solve the antenna issue as well...
Lacking such an antenna, I think WA5VJB's "Cheap Yagis" are a great way to
get started for low $$$. I'm gonna try to build a few this summer for two
reasons: 1) To see for myself how reproduceable these antennas are, and 2)
to have some antennas I can loan out if any of my "Joe706"
friends wanna try VHF contesting.
Just my $0.02
73, Dave/K8CC
James Duffey wrote:
> Hey Eric - Nice to hear from you on this topic. I was not advocating that
everybody operate with all homebrew equipment.
>
> Nothing wrong with commercial antennas, in fact I have a Cushcraft 13B2
that I rove with on occasion. It was given to me. I just like to build my
own antennas, and show other people how to build their own. Up to 432 MHz
at least, there are several good beam designs that work well as built with
no testing or tuning required, nor special tools or instruments, just
careful measurements. Sure you can tweak a bit more out of them with a bit
of test gear, or build antennas with slightly higher gain with some testing
and tuning, but for the beginner, better is enemy of good enough. The simple
designs should be enough to get them on the air quickly, cheaply and get
them hooked.
>
> I have given several talks on VHF contesting and roving over the past year
and a half. I always take a few antennas to show and people are always
amazed that simple homebrew antennas like the WA5VJB designs are available
and work well. I always get comments when I show the WA5VJB antennas like,
is that all there is to it? And hey, I can build that. My favorite: Does
that work as well as an Arrow? The guy with the 706/7000/FT100 or whatever
usually uses it on 2M and 70cm FM and that is it. If we can get those guys
on the weak signal modes, which the simple homebrew antennas they can do
without much investment, then we can hook some new blood into contesting.
Even getting the 706 guys who use loops to switch to beams would help a lot.
But getting guys on loops from verticals is a big step, if they do it for a
contest.
>
> At 6M, the N2MH version of the Moxon is easy to build from common
materials and is a great performer compared to the loop or dipole that the
guy may have been using. Again just careful lmeasurements are required and
pretty much all the parts can be purchased locally.
>
> I like the notion of distance scoring used in at least one contest and I
think that if a guy uses computer logging, like Roverlog, the distances are
calculated and scores calculated with no additional input from the user, so
it really isn't any more complicated. The Spring Sprints will use distance
scoring so we can all see what that is like.
>
> For those on the list that hadn't noticed yet, Eric has one of the
> greatest calls for VHF contesting there is. He is also one of the
> premier rovers in the Rocky Mountain Division and does a bang up job
> on 10 bands from that many or more grids, even in January. - Duffey
> _______________________________________________
> VHFcontesting mailing list
> VHFcontesting@contesting.com
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>
>
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