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Re: [TowerTalk] Sorry to bring up an oldie - Mast Material

To: "Rick Scott" <w7psk@yahoo.com>, "Towertalk reflector" <towertalk@contesting.com>
Subject: Re: [TowerTalk] Sorry to bring up an oldie - Mast Material
From: "Dave Hachadorian" <k6ll@arrl.net>
Reply-to: Dave Hachadorian <k6ll@arrl.net>
Date: Thu, 10 Mar 2011 08:45:28 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
The antenna is going to be 2' above the bearing?  I thought you 
said 4' yesterday. That changes everything.  I guess you didn't 
follow my inputs to the mast calculator.

I give up.

Dave Hachadorian, K6LL
Yuma, AZ




-----Original Message----- 
From: Rick Scott
Sent: Thursday, March 10, 2011 8:24 AM
To: K8RI on TT ; towertalk@contesting.com
Subject: Re: [TowerTalk] Sorry to bring up an oldie - Mast 
Material

PS
Im planning on getting 7 or 8 ft of material.  4ft for inside the 
tower and 3 -
4 ft above it.

I plan on mounting the Beam 2 - 3 Ft above the top.  I have a 
Mast Bearing in
the
top of the tower also.




----- Original Message ----
> From: K8RI on TT <k8ri-on-towertalk@tm.net>
> To: towertalk@contesting.com
> Sent: Wed, March 9, 2011 10:29:12 PM
> Subject: Re: [TowerTalk] Sorry to bring up an oldie - Mast 
> Material
>
> On 3/9/2011 4:24 PM, K7LXC@aol.com wrote:
> >
> > In a  message dated 3/9/2011 12:01:25 P.M. Pacific Standard 
> > Time,
> > towertalk-request@contesting.com writes:
>
>
> As Steve says, the tripod mount is likely the weak point and 
> not the
> current mast.
> I purchase 6061-T6 in 24' lengths with 1/8", 3/16"  and 1/4 
> wall. No, I
> would not recommend a 24 footer be used in your  tripod.  I'm 
> looking for
> some stronger alloy and temper.
>
> As for  your system I'd not go more than a few feet above the 
> tripod,
> unless the  roof is reinforced under the tripod and the tripod 
> is bolted
> to/through the  reinforcing and not just into the rafters.
>
> Wind is strange as to what  survives and what fails.
> I used to install TV antennas as a sideline back in  the 60's 
> and early 70's.
> At home I had a 5L 20 meter KLM on a 40' tower, a 6L  15 Meter 
> KLM on a
> 40' tower and a 7L 10 Meter Wilson (39' boom) on a 40'  tower. 
> These were
> relatively light steel towers on dirt bases and 3 way  guyed 
> just below
> the top of the tower.  Yes I needed larger towers but  that is 
> what I had
> at the time.
>
> I installed a new, fairly large TV  antenna just above the top 
> of a roof
> mounted tripod. This tripod had two lag  bolts in each leg that 
> ran
> nearly through the respective rafter in pre  drilled holes so 
> they
> wouldn't split the rafters.  Just a day or two  after 
> installing the TV
> antenna (remember I did a lot of these) we had a  rather strong
> thunderstorm. It literally split the rafters pulling the bolts 
> out and
> took the tripod right off the roof, destroying the antenna in 
> the
> process. Yet the wind did no damage to any of the big antennas 
> on the
> 40' towers.
>
> Just because a lightly built system survives a big storm,  does 
> not mean
> that system will normally, or can normally be expected to 
> survive
> another storm of the same intensity. Nature is  fickle!
>
> 73
>
> Roger (K8RI)
>
> >>   Im really  confused.  Id like to buy Local, because  the 
> >> mail order
> >  houses have
> > Really high prices and high shipping
> > plus  they  only do 5 or 10ft intervals.
> >
> >>   I have a Glen Martin  9ft  roof mount tower.  Its just shy 
> >> of 4ft from
> > the  rotor
> > to the top of  the tower.  Right now I have
> > a 2  1/2" Fence Post mast (really heavy  wall) that I hold an 
> > A4S up  with.
> >
> >>   A4 is going bad so I  decided to get my  dream antenna the 
> >> standard
> > SteppIR 3
> > element beam and   nothing else will go on the mast.  I would
> > like to get 8ft as  that  will give me 4ft above the tower, I 
> > can put the
> >  antenna
> > at 2 - 3 feet and  be ok.
> >
> > Hiya, Scotty  --
> >
> >
> >      The 3L SteppIR isn't appreciably  bigger than the  A-4 
> > you're currently
> > using. Go ahead and use what  you've got.
> >
> >      If you want to go a little  higher, use 1.5"  galvanized 
> > pipe (that's
> > the ID measurement - the  OD is 1.9"). The SteppIR  U-clamps 
> > are very snug
>for
> > a 2" mast so  they'll work FB on a 1.9" piece of  steel.
> >
> >       The main factor is that it's going on a  roof-mounted 
> > tower. The
tower
> > will likely blow off the roof before the mast  (whatever it 
> > is) bends.
> >
> > Cheers,
> > Steve     K7LXC
> >  TOWER TECH
> > and
> > _www.championradio.com_ (http://www.championradio.com)
> >
> >
> >
> >
> >  _______________________________________________
> >
> >
> >
> >  _______________________________________________
> > TowerTalk mailing  list
> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> >
>
>
> _______________________________________________
>
>
>
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>



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