I would go the Crank up route, unless you are happy to climb towers or don't
care about finding and paying for a professional to climb them. I figured
that the older I get the less likely I would want, or be able to climb.
I have a Tashjian LM-470, a 1980 vintage and the limit switches and motor
are all original, so I would not worry about that, just a little routine
maintenance takes care of that.
The LM-470 I like because of the way it lifts off ground level initially to
vertical and then tilts over at 8 feet above ground level in the opposite
direction to load your beams etc. and is counter balanced somewhat. US
towers forbid you to load antennas when tilted over.
Lightning who can tell, my uncle was fried in the UK standing on the ground
with 200 hundred 70 foot trees around him, all that was left was his hands
and feet. Logically you would think that the lower down something is, the
less chance of being struck. I would not worry about lightning as a factor,
just ease of operation and maintenance when you are old and infirm :- )
There are other issues like the concrete base needs to be bigger with crank
ups, but then you do not have to have those guy wires anchored.
Mike, K6BR
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Mat Eshpeter
I have searched the archives but have not been able to find an answer to my
question.
I am building a cabin on top of a tall ridge in West Virginia. I am
interested in putting up a tower next spring (between 55' and 72') near the
peak of the ridge and am trying to make a decision between crank-up vs
fixed. My concerns, in order, are 1) lightning, 2) ongoing maintenance, 3)
difficulty of installation.
Regarding lightning, my land is at the crest of a hill. From this hilltop
location, I am aftaid that my tower would be an ideal target for lightning.
The hill is 1600' above sea level, and many hundreds of feet higher than any
nearby hills. There are some tall trees within a couple hundred feet, but a
fixed tower @ 70' is making me nervous. A crankup tower, when fully
retracted, would be less than 25', perhaps offering less of a magnet for
lighting strikes. But given that the towers will be well grounded, I am not
sure if there would be much of a difference given that lightning would have
the option of 100' trees or a conductive tower at 25'
(crankup) / 70' (fixed). I would appreciate hearing from anyone with a tower
installed on top of a hill. Would the 45' height difference between 70'
fixed vs 25' retracted crankup have any meaningful effect on the probability
of lightning strikes?
Regarding maintenance, I have concerns about the crankup and associated
motor drive and limit switches properly functioning a few years down the
road, not to mention the cables and pulleys. I am looking at US Tower and
Tashjian crankups. The fixed tower would be a 70' Rohn 45G guyed twice for
each of the three anchors. From everything I have read about guyed Rohn
towers, other than annual inspection, there isn't any maintenance for quite
a few years. The crankup motor drive would be used quite often -- every time
I head up to the cabin to operate.When leaving the cabin, the crankup would
be lowered to its fully retracted height. This equates to approximately 3 or
4 raising/lowering cycles each month.
Regarding difficulty of installation, the crankups look to be more effort,
requiring heavy equipment to lift the tower off of the delivery truck, a
crane to mount the antennas, and about triple or more the excavation and
concrete. The fixed tower requires more land but I have 20+ acres to work
with.
My other options are 1) don't install a tower, or 2) put the tower lower on
the hillside in order to lower the probability of lightning strikes; this
would completely block my shot to the west and hurt my shot to the north and
south;my shot to the east would remain excellent.
The antenna that I am looking at is an M2 7-10-30LP8, but I am far from
decided. The option of "no tower" is not really an option; after 20+ years,
I feel it is time to talk to the DX.
Opinions appreciated, especially those with hilltop tower experience in
lightning-prone locations.
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