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Today's Topics:
1. RE: How to stiffen a mast (Keith Dutson)
2. Re: Ham II rotor went south and won't come back. (Bill Coleman)
3. Re: HamM-IV Mounting Screws (Bill Coleman)
4. Re: How to stiffen a mast (k2qmf@juno.com)
5. Re: How to stiffen a mast (Malcolm Ringel)
6. Re: Mast stiffness (Wayne Davidson)
7. do not use stainless (FireBrick)
----------------------------------------------------------------------
Message: 1
Date: Tue, 1 Feb 2005 11:19:23 -0600
From: "Keith Dutson" <kjdutson@earthlink.net>
Subject: RE: [TowerTalk] How to stiffen a mast
To: "'MIKE GREENWAY'" <K4PI@peoplepc.com>, "'Barkey, Patrick M.'"
<pbarkey@bsu.edu>, <towertalk@contesting.com>
Message-ID: <E1Cw1g4-00015I-00@pop-a065c32.pas.sa.earthlink.net>
Content-Type: text/plain; charset="us-ascii"
I agree that combining wood and metal helps with rigidity. You must make
certain that the wood is sealed against the elements to prevent weathering.
Fiberglass and/or epoxy coating makes it even more rigid. The floor pan in
my Corvette is actually made of fiberglass coated plywood that is bolted to
the steel frame.
Keith NM5G
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of MIKE GREENWAY
Sent: Tuesday, February 01, 2005 7:50 AM
To: Barkey, Patrick M.; towertalk@contesting.com
Subject: Re: [TowerTalk] How to stiffen a mast
I thought about this some years ago and had a friend turn some solid oak
dowels on his lathe that would just go into the mast. I used a hammer to
tap them into place but I brushed on epoxy just to take up any spacing
between the two. I capped the mast on both ends. It has been there for
years. I asked a structual engineer afterward about doing this and he said
they sometimes combine wood with metal to increase the strength. Whether it
is worth doing or not I cannot say but it made me feel a lot better.73 Mike
K4PI
----- Original Message -----
From: "Barkey, Patrick M." <pbarkey@bsu.edu>
To: <towertalk@contesting.com>
Sent: Wednesday, January 26, 2005 8:15 PM
Subject: [TowerTalk] How to stiffen a mast
I've been using 24 foot, half inch wall, 2.5 inch OD aluminum masts
on all of my towers for quite a few years, with no failures or real
problems. During the recent ice storm, however, a couple of them
flexed a little more than I'd like to see (they've since sprung back).
Now that I have the opportunity to think this over, I am wondering
if it would be of any value to try to add a little more stiffness to
the existing mast by driving something into the hollow center.
I've got a 1.5 inch ID hole to work with - perhaps some pipe or
solid rod could be driven into it?
Wondering if anyone has ever tried anything like this?
- Pat
N9RV
..
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
------------------------------
Message: 2
Date: Tue, 1 Feb 2005 12:18:52 -0500
From: Bill Coleman <aa4lr@arrl.net>
Subject: Re: [TowerTalk] Ham II rotor went south and won't come back.
To: replytojosh@tuel.com
Cc: towertalk@contesting.com
Message-ID: <582F94DA-7475-11D9-925A-000A95CC9FB4@arrl.net>
Content-Type: text/plain; charset=US-ASCII; format=flowed
On Jan 9, 2005, at 4:34 PM, Josh wrote:
> Hello all,
>
> My Ham II rotor went south today... literally.
>
> I was operating as usual when I release the break to turn the rotor, it
> turned itself south. Now it won't move out of that position.
Maybe the cable line for that direction of rotation shorted to the
brake line, and energising the brake causes it to rotate all the way to
the limit switch.
Could be a problem at the back of the control box, the terminals on the
rotator, or perhaps the cable itself.
Bill Coleman, AA4LR, PP-ASEL Mail: aa4lr@arrl.net
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901
------------------------------
Message: 3
Date: Tue, 1 Feb 2005 12:25:32 -0500
From: Bill Coleman <aa4lr@arrl.net>
Subject: Re: [TowerTalk] HamM-IV Mounting Screws
To: Skip Prinsen W1NNI <w1nni@cox.net>
Cc: towertalk@contesting.com
Message-ID: <46EBF87C-7476-11D9-925A-000A95CC9FB4@arrl.net>
Content-Type: text/plain; charset=US-ASCII; format=flowed
On Jan 19, 2005, at 12:02 AM, Skip Prinsen W1NNI wrote:
> Where can I get replacement screws for mounting my ham M-IV rotor to a
> rotor plate?
I went to the local Home Depot. I found stainless screws for my Ham-M
rotator without a problem. These were not hex head, but slotted. I
think they were 1/4", but I don't remember.
It shouldn't be a problem to find mounting screws for a rotator at any
hardware store. I'd get stainless. I also used a stainless split and
flat washer. I used a flat washer on each side of the rotator plate --
which helps to keep a small space between the rotator and the plate.
My rotator has been up 3.5 years with no slippage in any of the screws.
(Be sure to check your mounting hardware in your annual tower
inspection -- thermal cycling can work tight hardware loose)
Bill Coleman, AA4LR, PP-ASEL Mail: aa4lr@arrl.net
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901
------------------------------
Message: 4
Date: Tue, 1 Feb 2005 12:29:08 -0500
From: k2qmf@juno.com
Subject: Re: [TowerTalk] How to stiffen a mast
To: keith@dutson.net
Cc: K4PI@peoplepc.com, towertalk@contesting.com, pbarkey@bsu.edu
Message-ID: <20050201.122914.1276.2.K2QMF@juno.com>
Content-Type: text/plain; charset=us-ascii
How about filling the center of the mast with Viagra???
73, K2QMF
On Tue, 1 Feb 2005 11:19:23 -0600 "Keith Dutson" <kjdutson@earthlink.net>
writes:
> I agree that combining wood and metal helps with rigidity. You must
> make
> certain that the wood is sealed against the elements to prevent
> weathering.
> Fiberglass and/or epoxy coating makes it even more rigid. The floor
> pan in
> my Corvette is actually made of fiberglass coated plywood that is
> bolted to
> the steel frame.
>
> Keith NM5G
>
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of MIKE
> GREENWAY
> Sent: Tuesday, February 01, 2005 7:50 AM
> To: Barkey, Patrick M.; towertalk@contesting.com
> Subject: Re: [TowerTalk] How to stiffen a mast
>
> I thought about this some years ago and had a friend turn some solid
> oak
> dowels on his lathe that would just go into the mast. I used a
> hammer to
> tap them into place but I brushed on epoxy just to take up any
> spacing
> between the two. I capped the mast on both ends. It has been there
> for
> years. I asked a structual engineer afterward about doing this and
> he said
> they sometimes combine wood with metal to increase the strength.
> Whether it
> is worth doing or not I cannot say but it made me feel a lot
> better.73 Mike
> K4PI
>
>
> ----- Original Message -----
> From: "Barkey, Patrick M." <pbarkey@bsu.edu>
> To: <towertalk@contesting.com>
> Sent: Wednesday, January 26, 2005 8:15 PM
> Subject: [TowerTalk] How to stiffen a mast
>
>
> I've been using 24 foot, half inch wall, 2.5 inch OD aluminum masts
> on all of my towers for quite a few years, with no failures or real
> problems. During the recent ice storm, however, a couple of them
> flexed a little more than I'd like to see (they've since sprung
> back).
>
> Now that I have the opportunity to think this over, I am wondering
> if it would be of any value to try to add a little more stiffness
> to
> the existing mast by driving something into the hollow center.
> I've got a 1.5 inch ID hole to work with - perhaps some pipe or
> solid rod could be driven into it?
>
> Wondering if anyone has ever tried anything like this?
>
> - Pat
> N9RV
> .
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers",
> "Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041
> with any
> questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers",
> "Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041
> with any
> questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers",
> "Wireless Weather Stations", and lot's more. Call Toll Free,
> 1-800-333-9041 with any questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
------------------------------
Message: 5
Date: Tue, 1 Feb 2005 12:38:50 -0500
From: "Malcolm Ringel" <mringel@bluecrab.org>
Subject: Re: [TowerTalk] How to stiffen a mast
To: <keith@dutson.net>, <k2qmf@juno.com>
Cc: K4PI@peoplepc.com, towertalk@contesting.com, pbarkey@bsu.edu
Message-ID: <008d01c50884$ea7664a0$3e2f4845@DGG4W921>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
I'm surprised that it took this long to get there .....
73 ...sigh ...
Malcolm Ringel, K3KZ
----- Original Message -----
From: <k2qmf@juno.com>
To: <keith@dutson.net>
Cc: <K4PI@peoplepc.com>; <towertalk@contesting.com>; <pbarkey@bsu.edu>
Sent: Tuesday, February 01, 2005 12:29 PM
Subject: Re: [TowerTalk] How to stiffen a mast
>
> How about filling the center of the mast with Viagra???
>
> 73, K2QMF
>
> On Tue, 1 Feb 2005 11:19:23 -0600 "Keith Dutson" <kjdutson@earthlink.net>
> writes:
>> I agree that combining wood and metal helps with rigidity. You must
>> make
>> certain that the wood is sealed against the elements to prevent
>> weathering.
>> Fiberglass and/or epoxy coating makes it even more rigid. The floor
>> pan in
>> my Corvette is actually made of fiberglass coated plywood that is
>> bolted to
>> the steel frame.
>>
>> Keith NM5G
>>
>> -----Original Message-----
>> From: towertalk-bounces@contesting.com
>> [mailto:towertalk-bounces@contesting.com] On Behalf Of MIKE
>> GREENWAY
>> Sent: Tuesday, February 01, 2005 7:50 AM
>> To: Barkey, Patrick M.; towertalk@contesting.com
>> Subject: Re: [TowerTalk] How to stiffen a mast
>>
>> I thought about this some years ago and had a friend turn some solid
>> oak
>> dowels on his lathe that would just go into the mast. I used a
>> hammer to
>> tap them into place but I brushed on epoxy just to take up any
>> spacing
>> between the two. I capped the mast on both ends. It has been there
>> for
>> years. I asked a structual engineer afterward about doing this and
>> he said
>> they sometimes combine wood with metal to increase the strength.
>> Whether it
>> is worth doing or not I cannot say but it made me feel a lot
>> better.73 Mike
>> K4PI
>>
>>
>> ----- Original Message -----
>> From: "Barkey, Patrick M." <pbarkey@bsu.edu>
>> To: <towertalk@contesting.com>
>> Sent: Wednesday, January 26, 2005 8:15 PM
>> Subject: [TowerTalk] How to stiffen a mast
>>
>>
>> I've been using 24 foot, half inch wall, 2.5 inch OD aluminum masts
>> on all of my towers for quite a few years, with no failures or real
>> problems. During the recent ice storm, however, a couple of them
>> flexed a little more than I'd like to see (they've since sprung
>> back).
>>
>> Now that I have the opportunity to think this over, I am wondering
>> if it would be of any value to try to add a little more stiffness
>> to
>> the existing mast by driving something into the hollow center.
>> I've got a 1.5 inch ID hole to work with - perhaps some pipe or
>> solid rod could be driven into it?
>>
>> Wondering if anyone has ever tried anything like this?
>>
>> - Pat
>> N9RV
>> .
>>
>> _______________________________________________
>>
>> See: http://www.mscomputer.com for "Self Supporting Towers",
>> "Wireless
>> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041
>> with any
>> questions and ask for Sherman, W2FLA.
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk@contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>> _______________________________________________
>>
>> See: http://www.mscomputer.com for "Self Supporting Towers",
>> "Wireless
>> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041
>> with any
>> questions and ask for Sherman, W2FLA.
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk@contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>> _______________________________________________
>>
>> See: http://www.mscomputer.com for "Self Supporting Towers",
>> "Wireless Weather Stations", and lot's more. Call Toll Free,
>> 1-800-333-9041 with any questions and ask for Sherman, W2FLA.
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk@contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
> any questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
------------------------------
Message: 6
Date: Tue, 01 Feb 2005 10:11:02 -0800
From: Wayne Davidson <wdavidson@tower-structures.com>
Subject: Re: [TowerTalk] Mast stiffness
To: jimjarvis@ieee.org
Cc: towertalk@contesting.com
Message-ID: <41FFC636.6A88F64F@tower-structures.com>
Content-Type: text/plain; charset=us-ascii
This type of deflection problem is well known to structural
engineers. The problem may be associated with vortex shedding
and structural resonance. In which case, the pipe may go through
very substantial amplitudes of vibration under relatively low
wind forces.
On the other hand a 25' tall by 2.5" O.D. pipe is very slender
and relatively flexible. It could simply be experiencing
large deflection due to the applied wind loads or in response
to wind gust effect.
Wayne Davison, SE, CE
Jim Jarvis wrote:
> When this thread started, I just KNEW someone would
> throw in Viagra.
>
> At the outset, this was about some 2.5" od, 0.5" wall
> 24' STEEL masts. The complaint was, "they flexed more
> than I was comfortable with <snip> but they since came
> back." It wasn't clear whether they took a set, and
> somehow recovered, or if they simply flexed and returned
> to normal when the load was removed.
>
> I suspect it was merely flexing, because once overstressed
> and deformed, I've never seen metal return to its original
> shape. As a result, I suspect this may be a non-problem.
>
> If in doubt, get an M.E. to look up the properties of the tube
> in question, then calculate the windload upon it, given the conditions
> you think prevailed at the time of observation. Was the load
> anywhere near close to the tube's rating? (I'd betcha it wasn't)
>
> With respect to using wood to add strength to a tube...I doubt
> oak would do much for steel, but in the case of aluminum, which
> has a much higher modulus of elasticity, and lower strength, a
> properly fitting oak dowel WILL significantly increase the strength
> of the tube. Reason? It keeps the wall from deforming, adds its own
> strength to the structure, and it tends to deflect less than aluminum.
> Again, an M.E. would have to run the numbers to see how much
> improvement you get...but I'm betting it's substantial.
>
> In closing, I'd like to see someone LIFT a 2.5" od solid steel
> rod, 24' long, let alone get it vertical into a tower.
> Totally Tubular (TT) is the only way to go, dudes.
> (this WAS a west coast question, wasn't it?)
>
> N2EA
> jimjarvis@ieee.org
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
any questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
------------------------------
Message: 7
Date: Tue, 1 Feb 2005 12:30:14 -0600
From: "FireBrick" <w9ol@billnjudy.com>
Subject: [TowerTalk] do not use stainless
To: "TowerTalk List" <towertalk@contesting.com>
Message-ID: <00a001c5088c$12895180$6501a8c0@HS2>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
screws or bolts to mount a rotor to a mounting plate.
I've been told by both the rotator repair men this.
And many towertalkians have agreed.
when that stainless bolt breaks or gauls.
You will be swearing mightlily.
Darn near impossible to drill out a broken stainless bolt without damaging
the threads.
-----------------------------------------------------
Windows:(n.)2. The Gates of hell.
-----------------------------------------------------
Bill H. in Chicagoland
------------------------------
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End of TowerTalk Digest, Vol 26, Issue 4
****************************************