Your Pointy Rohn 25 and a shelf
K7LXC at aol.com
K7LXC at aol.com
Sat Apr 13 19:05:10 EDT 1996
In a message dated 96-04-13 06:54:53 EDT, you write:
>Flat top sections are better. Why? Becuase you can stand on them
>when you are working on that upper stacked yagi or the truss for your beam.
>You can't find a place to step anywhere near the top of a pointy section.
Hiya, Jim --
Always a pleasure to hear from you and great advice from an experienced
tower builder, someone who has obviously been there before.
>
>The second shelf for a thrust bearing is a must for ease in rotor/rotator
>instalation and maintenance work. By having the shelf above the rotor you
>have a point where the downward weight of the mast and antennas can be born
>when it is time for you to take out the rotor for service.
Another option is to have most of the mast in the tower or at least
enough to get the center of gravity below the top of the tower. Then the
system can just sit there. It's captured by the tower so it really can't go
anywhere. This'll work if you don't want to go to the added expense and work
of a second accessory shelf and thrust bearing. This second thrust bearing
becomes more important with larger systems and less important with smaller
ones.
>If the clamp is applied to the
>mast just above the new shelf above the rotor it now takes the weight of the
>antennas when you need to remove the rotor. If you take a pry bar up the
>tower (don't drop it!) you can goose the mast/ants up a liltlle before you
>tighten that toothed clamp up above. When the rotor is back in place up top
>on the rotor shelf you loosen the toothed clamp and the mast will slide back
>down to the rotor....note: (K7LXC probably will back me up on this) most
>rotor manufacturers encourage the weight of the antennas to be carried on
the
>rotor as opposed to the mast being supported vertically by a thrust bearing.
Right again, Jimbo. The rotators are designed to have some amount of
preload on them. To be honest with you, I don't know what that factor is.
Also, I haven't figured out how to measure it anyway. SOME preload force is
recommended.
>To keep the mast from spinning around, I take a short length of pipe with a
>boom to mast clamp on one end of it and attrach it to the mast someplace
>within the tower. You can then lash this pipe to a tower leg and the antenna
>will not windmill on you.
More sage advice. This would make a good article for the NCJ (hint,
hint).
73, Steve K7LXC
>From Sante ( IK0HBN )" <ik0hbn at isa.it Sun Apr 14 01:46:50 1996
From: Sante ( IK0HBN )" <ik0hbn at isa.it (Sante ( IK0HBN ))
Date: Sun, 14 Apr 1996 02:46:50 +0200
Subject: EL emergency and call for help.
Message-ID: <1.5.4.16.19960414004742.300f8826 at net.isa.it>
I would like to remember that EL2PP gave in a not far past the pleasure of
working EL mult. in several contests: now sincerely I can understand that EL
tragedy doesn't hurt everybody, but it don't seem a right and human way to
thank Monica.
73 de Sante IK0HBN
At 15.35 13/04/96 -0400, you wrote:
>Trey, First, I only sent two messages on two different days noting the
>possibility of ELs using the ham bands to call for help. If two postings,
>on what could have been a life-saving topic that should be (and by
>regulation, practice, and likely law--is) of vital concern to all hams
>who could provide assistance,
>among all the other things that appear here are too much, I recommend you
>re-examine your value system and the deepest reasons ham radio exists.
>For a tiny drop of good will for humanity, I wish you warmest 73, K4VUD
>
>On Fri, 12 Apr 1996, Trey Garlough wrote:
>
>> X-Mailing Address: 101 Cooper Street, Santa Cruz, CA 95060
>>
>> > A call for help in a real emergency when life is in danger is never
>> > crap. I feel sorry for you to think otherwise.
>> > One of the problems with SOME contesters is that they are selfish.
>> > Surely you would share a message on this reflector if it could do any
>> > good in a real emergency--which we have. Shame on you.
>>
>> In a very narrow sense, I agree, but for the most part I disagree. Your
>> previous message (the one that said something like "the 4U1UN emergency
>> net will be QRV today because we are going to talk to some EL's -- please
>> don't QRM us") was so incredibly ponderous that I doubt it was really
>> worth the bandwidth on CQ-Contest.
>>
>> By the same reasoning, we should see weekly posts here that say "don't
>> climb your tower without wearing a safety belt" and "don't eat poison"
>> because "if just one life is saved, it will be worth the consumed
>> bandwidth." I disagree.
>>
>> You have gotten the word out about the EL situation with your first few
>> messages. At this point, I believe you should move this thread elsewhere
>> because CQ-Contest is neither the right mailing list nor the right audience
>> to pursue this thread about the EL situation.
>>
>> --Trey, WN4KKN/6
>>
>
>
Sante LILLO (IK0HBN)
Localita' Saineta, 3
01030 Bassano in Teverina (VT) Italy
home telephone: +39 (0) 761-407543 (FAX on request)
E-mail: ik0hbn at isa.it
packet adr: IK0HBN at I0INU.IUMB.ITA.EU
DX cluster : IK0HBN > I0JBL-6
>From Big Don <bigdon at eskimo.com> Sun Apr 14 03:40:30 1996
From: Big Don <bigdon at eskimo.com> (Big Don)
Date: Sat, 13 Apr 1996 19:40:30 -0700 (PDT)
Subject: Falling Trees (was: Greasing Crank-Ups)
Message-ID: <Pine.SUN.3.92.960413185853.28739C-100000 at eskimo.com>
On Sat, 13 Apr 1996 K7LXC at aol.com wrote:
> In a message dated 96-04-13 14:42:46 EDT, you write:
> > Over the years I've destroyed crank ups by over loading them, poor
> >maintainence and putting them in the paths of trees that later fell! I'm
> >becoming an expert simply by making all the mistakes!
>
> Ouch! Learning the hard way has its pros and cons to be sure. At least
> no one was injured during your education. I hope that these posts will help
> to keep people out of trouble by spreading good information that they can
> use.
My neighbor has a couple of trees just on his side of the property line
that, given the prevailing direction of our stronger windstorms, are
prime candidates to take out one of my tower guy sets, if the trees
snap. They are notoriously brittle alders and highly-exposed in an open
area and they are rather sick-looking.
Although Big Don ranks poorly in the diplomacy department, during one of
our conversations, the topic of those trees and windstorms just happened
to come up ;) I sort of mumbled out loud something to the effect of
wondering how one's homeowner's insurance would view it if there was a
known hazard that nothing had been done about prevention-wise, that
resulted in said homeowner's insurance having to replace a neighbor's
expensive tower/antennas. Not quite that blunt but that was the gist of
it.
Neighbor gave me permission to guy the trees. Nice thing about this is
they only needed guying in one direction. Now they can still snap, but
the guys should then cause them to fall harmlessly sideways, that's the plan
anyway...
I had enough spare hardware, and there was a massive stump conveniently-
placed, already there for a guy anchor. Quick like a bunny before he
could change his mind it was done.
Big Don
>From oo7 at astro.as.utexas.edu (Derek Wills) Sun Apr 14 05:09:27 1996
From: oo7 at astro.as.utexas.edu (Derek Wills) (Derek Wills)
Date: Sat, 13 Apr 1996 23:09:27 -0500
Subject: EL emergency
I would like to remember that EL2PP gave in a not far past the
pleasure of working EL mult. in several contests: now sincerely
I can understand that EL tragedy doesn't hurt everybody, but it
don't seem a right and human way to thank Monica. (IK0HBN)
It's also a sad reminder of events there about 6 yrs ago. Used to
hear Willy EL7X's slightly raspy CW signal, worked him on 5 bands,
I think he was killed back then. I had a bureau card from him just
a while ago (the oversize one with elephant sketches on it), it brought
back memories - it would be nice to think that he is still alive even
if not on the air. It's hard sometimes to remember that these are
real people and not just mults in CONTESTs.
Derek AA5BT
oo7 at astro.as.utexas.edu
>From w2vjn at rosenet.net (George Cutsogeorge) Sun Apr 14 12:57:43 1996
From: w2vjn at rosenet.net (George Cutsogeorge) (George Cutsogeorge)
Date: Sun, 14 Apr 96 11:57:43 GMT
Subject: Replacing cables, etc.
References: <960413160702_374791016 at mail06>
Message-ID: <M.041496.045743.47 at ppp054.rosenet.net>
K7LXC wrote:
>
> As far as replacing the cables and pulleys every three years, YOU'VE
> GOT TO BE KIDDING. In most of the crankup towers I've seen and
> particularly
> the motorized ones, these are jobs to be done at the factory or by a
> factory
> tech ONLY.
Send a crank up back to the factory? YOU have got to be kidding. Replacement
cables cut to length with the ends done at the factory are available from the
manufacturers as are pulleys. Mine are held in with roll pins which I drive
out with a steel rod. It took all of an hour or so to replace both cables and
the pulleys.
This is the third crank up I have owned and it doesn't take a rocket scientist
to maintain them.
----
George Cutsogeorge, W2VJN
Umpqua, OR.
>From AA7BG--Matt <AA7BG at worldnet.att.net> Sun Apr 14 11:44:07 1996
From: AA7BG--Matt <AA7BG at worldnet.att.net> (AA7BG--Matt)
Date: Sun, 14 Apr 1996 10:44:07 GMT
Subject: Your Pointy Rohn 25 and a shelf
Message-ID: <199604141044.KAA01676 at mailhost.worldnet.att.net>
>The second shelf for a thrust bearing is a must for ease in rotor/rotator
>instalation and maintenance work. By having the shelf above the rotor you
>have a point where the downward weight of the mast and antennas can be born
>when it is time for you to take out the rotor for service.
Jim, This is something I've been pondering as of late. Actually, the second
shelf doesn't need a thrust bearing. Is this what you're saying? I've heard
of just using a muffler clamp above the second shelf to hold the weight, but
I suppose the Hy-Gain clamp would do a nice job. I know a lot of the guys
seem to drill the second shelf and add a thrust bearing, I can definitely
see the value of the second rotor shelf, but I just don't see what you gain
with the second thrust bearing.
Further, if one drills the upper rotor clamp and mast leaving a 1/4" gap or
so above the rotor housing, then the mast (weight held by the thrust bearing
at top of tower)doesn't even have to be moved up when changing out rotors
and you wouldn't even need any sort of clamp at the second rotor shelf. Just
prevent the mast from twirling, pull the bolt, slip out the rotor and the
2nd rotor shelf will keep the mast from kicking out the side of the tower. I
know this set-up doesn't put the weight on the rotor as you advocate. I
guess these topics come up every antenna season and there's as many opinions
as there are contestors.
73
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AA7BG at worldnet.att.net Matt Power, Montana
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