Hi Jeff,
Good questions, all.
As long as the tower is in good shape, it shouldn't matter how old it is.
Check for rust. Check all cross-brace to leg connections for sturdiness. And
most important -- BUY A NEW BOLT KIT. On a freestanding tower such as the
BX, the bolts are to safety what the sun is to sunshine. IT IS NOT WORTH
REUSING OLD BOLTS. Buy from Rohn if you can. If you can't, only buy from
your most-trusted source for fasteners and duplicate the Rohn specs for
strength.
If you learn nothing else from this exchange, learn that. Do not reuse old
bolts. They are cheap enough that it's just not worth skimping.
I would be more concerned with the other components in the system. The
trapped tribander may be OK, or the element to boom clamps have been
overtightened, there's oxidation between element joints, the traps are
faulty, etc. Old antennas can be headaches, particularly for newcomers to
yagidom.
The rotator may be another area of concern. Before you put it back up, make
sure it doesn't need any dentistry. Ham-X style rotators can be prone to
lost teeth in the gears. Check the direction-indication pot to make sure
there's 500 ohms from one end to the other. A burned-out connection at one
end is not uncommon. Clean the pot's wiper arm. Make sure all the ball
bearings are there. Put it back together with a thin coat of white lithium
grease on the bearing races.
Rotators are repairable, so don't consider the state of the rotator as a
deal-breaker. Just be aware.
Also, plan on about $500-$600 worth of concrete and rebar as a base. Only do
what Rohn says to do for a base. Do not try to skimp here, either. You
wouldn't want the tower to take out your neighbour's house and then have
your insurance carrier deny liabilty coverage, would you? They won't have
much to argue with if you followed the manufacturer's instructions.
Here's my advice: as long as it's in OK shape, take the free tower and all
the other stuff. Check it all out, but don't be surprised if the HF beam has
to say bye-bye. The two-meter yagis should be OK, depending on the feed
system. Ringos are pretty indestructible.
If nothing else, the HF beam may provide enough aluminum for your interim
rotatable dipole.
Good luck. Don't be afraid to economize, just remember to do it properly.
73, kelly
ve4xt
----- Original Message -----
From: "Jeff Burns" <jhburns@attglobal.net>
To: <towertalk@contesting.com>
Sent: Wednesday, September 25, 2002 3:27 PM
Subject: [Towertalk] Iis a "free" tower a good deal?
> I have been hoping to expand my antenna system beyond my simple random
wire,
> but had not thought I would be able to do anything at this time because of
> the cost. Then I was offered a standing tower and associated antennas. I
am
> in the process of deciding if I can afford this "free" system. Someone
> suggested that this group would be a good place to ask my questions.
>
> Before I ask about the tower I have been offered; let me give you enough
> information about me, and my QTH, to be able to intelligently answer my
> questions.
>
> I have been a Ham for 2+ year. My equipment consists of an Elecraft K2
with
> the antenna tuner, Ten-Tek 6m transverter, VX-150 2m HT, and a 2m brick
amp.
> I only use the 2m stuff to keep in contact with my wife, and participate
in
> a few local Radio Club activities. I picked up the transverter at a ham
fest
> recently and have done little more than verify it works. Most of my time
is
> spent on HF. For the first year I worked SSB, but now I mostly concentrate
> on CW. My goal is to improve my CW skills form the 10-12wpm into the
> 18-20wpm range. Later I expect to get into DXing using both phone and CW.
>
> My QTH is a moderate sized suburban lot outside the city limits. No legal
> restrictions on antennas, but I do wish to keep the neighbors happy. The
> house is a single story ranch. The back of the house is 43-ft from the
power
> lines. A tower placed on the side of the house could be farther from the
> main power line, but would be closer to the neighbors power feed, and
trees
> that would require yearly trimming to stay clear of the antennas. At this
> QTH I know I cannot put up a super contesting station, but I would like
> something better than my current wire.
>
> If I had no concern for the cost of an antenna system, and was convinced I
> would not move for many years I would put up something like this:
> - 40 ft self supporting tower
> - 3 Element SteppIR
> - 100' Doublet supported at the center by the tower. A tall tree in
the
> front yard would support one end. The other end would slope to the top of
th
> e fence in the back. This would be fed with ladder line.
>
> Given the cost of such a system I have been thinking of using a
lightweight
> temporary mast instead of a tower, and using a rotatable dipole instead of
> the yagi. The guide wires for a lightweight mast are a problem because the
> house is in the way and my wife objects to them. A rotatable dipole 35-ft
> long and feed with ladder line sounds like a good idea. It should be
tunable
> on all bands from 30 to 10m, and would not be objectionable to look at.
>
> The wife of a Ham with Alzheimer's has offered me the following system
free
> if I take it down. It was probably put up in 1960.
> - BX-56 Tower in good shape
> - Trapped HF beam; three elements but two are close together at one
end
> so I am not sure exactly what it is.
> - 2 eleven element 2m beams phased together
> - 2m ringo
> - Rotor; mounted just above the third tower section from the bottom;
> probably a ham IV but I am not sure.
> If I put this up I would probably only use 40-ft of the tower making it an
> HDBX-40.
>
> Now my questions:
> 1. Is this system a good deal?
>
> 2. Is it well suited to my situation?
>
> 3. Are antennas this old worth messing with or should I sell them off and
> use something newer? Maybe I should make a rotatable dipole and start
saving
> for the SteppIR.
>
> 4. I know of an HDBX-48 that is on the ground and freshly panted that I
> could purchase for $200. Would this be a better deal?
>
> 5. Is putting up a used tower being penny wise and pound-foolish? Should I
> just save for a couple for years and get new equipment?
>
> Jeff Burns
> AD9T
>
> _______________________________________________
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