[TowerTalk] Planning First Beam and Installation - Comments Please
ke3q at msn.com
Wed May 10 14:40:25 EDT 2006
Years ago as a teenager, being on a MUCH more limited budget than your $800 "warchest," I put a chimney mount on the low chimney of my parents' house, which must have put the antenna all of about 20' off the ground. It was a two-element 15 Yagi, that was on the cover of QST magazine in 1967. It worked very well, so I got out the ARRL Antenna Book, did the math, and added some length to the boom and a third element. Again, it worked great and my first QSO was VS9ASP, a very rare one, who had a pileup going on 21030. Got him first call; it was memorable.
I didn't much know what I was doing on such things so the mechanical aspects of my installation were "marginal," but did get by. For instance, for the mast I used a standard 1-1/4" TV mast, standard chimney mount hardware, the Yagi boom was also 1-1/4" TV mast, etc. Still, it worked, and for a small installation I'd say was sufficient. I think the idea of going with a properly-installed chimney mount is a good one. Upgrading to a better mast than what I used is a good idea. Shopping around for the best quality chimney mount hardware is a good idea. You may want to consider "doubling up" the chimney mount hardware -- that is, instead of two "mounts," use four.
I'm not familiar with those tribanders, but suggest you also consider the Cushcraft A3, which I have found to be a fine small tribander, simple, very inexpensive used (e.g. $100 or less), and it works. K3TW used one for the several years he was on from Tanzania, 5H3TW, and was S9 plus day after day.
The TA-33 and TH-3 would also be good choices. Also widely available used for a pittance, e.g. $50.
The Force-12 C3 variants are apparently quite good but do have fullsize elements. The Bencher Skyhawk deserves a look, designed by WA3FET. I've noticed new tribanders or any Yagis, given the cost of aluminum these days, are expensive; used ones are cheap; most people seem to prefer to buy new despite the expense, depressing the price of used ones. Maybe it's because this sort of antenna is a "first and only," so guys decide to treat themselves by being able to open the box on a brand, spanking, new one, a gift to themselves.
To stay within budget, try to find a used rotator, e.g. Yaesu 800 or Ham-IV. Be sure to use lugs on the wire-to-rotator connection, waterproof well to avoid maintenance (to keep it reliable), etc. For a smallish beam (like what I put up in '67) even a TV rotator could be adequate. Last I checked they were pretty inexpensive, even new.
Don't expect miracles from 10M in particular, and even 15M, until we get a little bit up the other side of the sunspot cycle. We're at the bottom. In a few years even a small tribander will do quite well for lots of DX; right now it's a little tougher.
73 - Rich, KE3Q
----- Original Message -----
From: Kevin der Kinderen<mailto:kkinderen at gmail.com>
To: towertalk at contesting.com<mailto:towertalk at contesting.com>
Sent: Wednesday, May 10, 2006 1:34 PM
Subject: [TowerTalk] Planning First Beam and Installation - Comments Please
I live in an apartment building. My landlord is allowing me to install a
beam if I keep it small. He's asking to see my plans before a final
commitment. I've never had a beam up before and in my research I'm finding
that it's a little more involved than putting up a TV antenna. So, I wanted
to run my skeleton plan by the pros here and get some comments and fill-ins.
Goals (in order of importance):
* Sturdy - I've lived in the Roanoke/Blacksburg area about two years. There
has been some memorable winds coming down through here - gusts as high as 80
mph. Ice seems to be a big problem in the winter.
* Small size to be less obtrusive, easier to install (the landlord and his
crew will do the mounting).
* Performance improvement over the 125' doublet I have up now. Especially on
20 meters and higher most signals look very weak to me usually only peaking
at S-3 or less.
* Cost - I need to stay very reasonable. Total installation cost should be
no more than $800 (I can stretch this very little).
* The building I live in is made up of an old bank and store fronts - all
converted to apartments. I live in one of the store fronts beside the bank.
The building seems to be made of brick with wood beams. The peaked roof over
the bank is tin. The flat roof over the shops is below and to the right of
the peaked roof. It is gravel and tar.
* The surrounding land slopes from the front of the building to the back.
>From the front, I'm on the first floor. From the back (where my shack is)
it's the second floor and there is one more floor above me.
* Once the antenna is in the air, I will have no access to it. I can't
expect the landlord to come down and do repairs or preventive maintenance on
it. I will not be allowed up on the roof.
* The people that will be doing the installation are not hams and have never
installed an antenna that I'm aware of.
Antenna and Component Selection:
* I have looked at both the Teledyne T-6 and Cushcraft MA5B. I think the
MA5B might be more suitable though I really like what I've read about the
T-6. The MA5B is smaller and because of that I think might withstand the
winds and ice better. I understand these smaller antennas won't have the
performance of a full-sized beam but it should be significantly better than
my doublet on 20/15/10.
* I will probably do the chimney mount and try to clear the tin roof.
* I have not selected a rotator.
Problems: (comments definitely appreciated here)
* There are two mounting positions I could try. One is a chimney. This would
place the antenna over and at the edge of the tin roof. The other is on the
flat part of the roof but I wouldn't be able to get the antenna high enough
to clear the tin roof. I'm leaning towards the chimney mount and hoping the
tin roof won't have a huge impact on the antenna. Someone suggested that
with a tin roof I might be better just going with a vertical but I don't
think that will provide a significant improvement over the doublet.
* If mounting to the chimney (or any other mounting location for that
matter), I don't have a good understanding of all the components involved.
Is the installation as simple as a few (3 or 4) Y-brackets for the chimney
held in place with steel bands? From there, I'd put a few sections of tube
together to get the antenna about 5 to 10 feet above the chimney. I would
mount a small rotator to the top of this and the antenna on a short (1 or 2
feet) section of tubing on top of the rotator.
* Is this plan reasonable? Will the tin roof make the installation
ineffective? Will the wind and ice take down the antenna within the first
year? Should I just live with the doublet?
That's my story. Any hope for this apartment dweller? I can't believe I have
a landlord that has been so cooperative with my hobby. I'd definitely like
to take advantage of the situation he offers and not cause him any problems
with the installation.
Kevin - K4VD
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