[TowerTalk] Re: Tower Talk Digest V3 #305
Barry Kirkwood
bjk@ihug.co.nz
Wed, 16 Aug 2000 09:56:51 +1200
I would much appreciate 2536, if you are not snowed under.
73 es tnx
Barry Kirkwood PhD ZL1DD
Signal Hill Homestay B&B
66 Cory Road
Palm Beach
Waiheke Island 1240
NEW ZEALAND
www.waiheke.co.nz/signal.htm
----- Original Message -----
From: Tower Talk Digest <owner-towertalk-digest@contesting.com>
To: <towertalk-digest@contesting.com>
Sent: Friday, 11 August, 2000 3:48 PM
Subject: Tower Talk Digest V3 #305
>
> Tower Talk Digest Thursday, August 10 2000 Volume 03 : Number
305
>
>
>
> In this issue:
>
> Re: [TowerTalk] Tower Base Technology
> [TowerTalk] Hy-Tower Extension?
> Re: [TowerTalk] 4 square arrays
> Re: [TowerTalk] Rohn Info
> Re: [TowerTalk] Tower Base Technology
>
> See the end of the digest for information about towertalk-digest
>
> ----------------------------------------------------------------------
>
> Date: Thu, 10 Aug 2000 21:31:03 -0400
> From: "David Siddall" <drsiddall@verner.com>
> Subject: Re: [TowerTalk] Tower Base Technology
>
> Mike -
>
> I've put two HDBX-48 towers up. One was in sand (on Cape Cod) but about
5.2 cubic yards held it even through a hurricane (with Ham-IV, TH5DX 2'
above top (50' above ground). (The base is still there in HyannisPort if
anyone looking to buy a house up there with the base already installed . . .
.)
>
> Other was in rocky soil in West Virginia, again I used just a little over
5 cubic yards with no problem. In sand, it was held pretty much purely by
the weight of the concrete; in WV, I dug a ridge about 6 inches into the
rock/soil around bottom; and also made to bottom a little larger than the
top to provide a little better hold.
>
> Bottom line is, the recommended 5 cubic yards (this is my memory of being
equal to slightly exceeding spec) will hold it in just about anything; that
is, at least until the torque starts popping rivets on your top section with
that antenna. . . but screws can fix that if watched. [ Mine was fine until
I put a KT34XA on it - knowingly serious overload - and steady winds of
70 -80 miles caused a little damage. If you know W9LT, he could tell you
about that - it happened on a November contest weekend when he was single
op'ing, up on the mountaintop. But that was serious torque, a 34-foot boom
being substantially greater than the recommended 10-foot one. The 18-foot
TH5DX came through even high winds without damage. One thing about Rohn - I
have always found them conservative on their ratings. Now that I am older,
however, I follow them closer. And I always exceeded on bases and anchors
for simple safety reasons. ]
>
> Dave K3ZJ
>
> >>> "Mike Foerster" <mike.foerster@home.com> 08/10/00 08:58PM >>>
>
> Guys,
>
> I'm new to the group, got a reference to ask the TowerTalk bunch my
> question.
>
> I just purchased a used (6 year old) 48ft Rohn HDBX 48, TH11DX and
> Tailtwister rotor. Had to take it down and it was in dire need of some
boom
> to mast repairs. I've got that taken care of.
>
> Now for the question. The mfg. specs call for a big block of concrete
> buried in the ground. Brute force style.
>
> Has anyone done any engineering using some technology to help to keep the
> tower erect safely, other than just the big block?
>
> *Something like digging post holes in the bottom 4 corners of a bit
> smaller pit and putting in some re-bar and then pouring concrete
>
> *Or perhaps a "+" shaped hole to use more of the dirt/clay to press
> against vs the big block effect.
>
> *Is one shape (square, round, tall, short,tapered, etc.) better than
the
> others?
>
> *Differences in the ground makeup (sand, clay, rock)?
>
>
> This (Rohn) tower technology is about 20 years old (as is the book that
> tells me how much concrete is required). There has to be a better way
>
> I know about following the mfg. specs, liability, warnings about twist,
etc.
>
> I'm just asking...
>
> Mike
>
>
>
>
>
> - --
> FAQ on WWW: http://www.contesting.com/FAQ/towertalk
> Submissions: towertalk@contesting.com
> Administrative requests: towertalk-REQUEST@contesting.com
> Problems: owner-towertalk@contesting.com
>
> ------------------------------
>
> Date: Thu, 10 Aug 2000 21:29:37 -0400
> From: "Jeff Maass" <jmaass@columbus.rr.com>
> Subject: [TowerTalk] Hy-Tower Extension?
>
> I have a Hy-Tower which forms a portion of the vertical part of
> my 160m inverted-L. I've eliminated all of the Hy-tower parts
> (stubs, stinger, etc.) except for the tower on it's insulated base,
> and I've added my own extended mast. I'd like to make the
> tower portion a bit taller to extend the overall length, perhaps
> an additional 20-40 feet with guying.
>
> Is there any source of additional sections of tower that can be
> used to increase the height of the tower portion? Will new Rohn
> BX or HDBX tower sections mate up with it?
>
> 73,
> Jeff Maass jmaass@columbus.rr.com Located near Columbus Ohio
> USPSA # L-1192 NROI/CRO Amateur Radio K8ND
> Maass' IPSC Resources Page: http://home.columbus.rr.com/jmaass
>
> ------------------------------
>
> Date: Fri, 11 Aug 2000 01:39:04 -0700
> From: Tom K Osborne <w7why@juno.com>
> Subject: Re: [TowerTalk] 4 square arrays
>
> On Thu, 10 Aug 2000 05:16:34 -0600 n4kg@juno.com writes:
>
> > As others have also indicated, current flow into a severly tapered
> > element is minimal, meaning that a thin tube at the end of a thick
> > element provides little additional loading. You need a capacity hat
> > or fat element to effectively extend a conductor.
>
> That is an interesting point. I have been thinking of doing something
> with my tower here. It is pretty short, 35 feet, with a 2 el 20 meter
> monobander on it. I was wondering what would happen if I put a 15 or 20
> foot piece of aluminum tubing on top--would that make it think it was
> longer?? 73
> Tom W7WHY
> ________________________________________________________________
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>
> ------------------------------
>
> Date: Thu, 10 Aug 2000 18:58:10 -0700
> From: Michael Tope <w4ef@pacbell.net>
> Subject: Re: [TowerTalk] Rohn Info
>
> Hi Stan,
>
> I just noticed the Rohn drawings for TVRO
> applications with EPA of 49 sqft last night
> while purusing my new Rohn consumer catalog.
> This is interesting in light of discussion
> I have had recently on the reflector regarding
> the strength of the BAS25G accessory shelf
> top section. If you look at these drawings,
> you will notice that in the TVRO application,
> the antenna is mounted on a top plate which
> goes directly on top of a 25G section. Thus
> it has Z bracing all the way to the top,
> unlike the BAS25G which leaves out Z bracing
> on the top 2' of the tower. Notice also, that
> this installation is guyed at the top plate
> with a torque arm assembly.
>
> Mr. Tower2sell is making a believer out of me.
>
> Mike, W4EF...................................
>
>
> ********************************************
> Michael C. Tope, W4EF
>
> email: W4EF@pacbell.net
> web: www.dellroy.com
> ********************************************
>
>
>
> - ----- Original Message -----
> From: "Stan or Patricia Griffiths" <w7ni@teleport.com>
> To: <towertalk@contesting.com>
> Sent: Thursday, August 10, 2000 5:57 PM
> Subject: [TowerTalk] Rohn Info
>
>
> >
> > I have investigated how I can distribute small bits of
> > interesting Rohn information and stay out of trouble with
> > everyone at the same time. Rohn has copyrighted all of the
> > drawings and catalog pages and will not give me permission
> > to publish any of them. They will, however, allow me to
> > copy individual sheets from Rohn Catalogs and mail them to
> > individuals who ask.
> >
> > I consulted an attorney who told me that emailing an
> > individual scanned copy to an individual person who requests
> > one is really the same as sending a hard copy through snail
> > mail.
> >
> > So here is what I am willing to do, until I get swamped with
> > too many requests, anyway. Below is a list of Rohn Catalog
> > pages that have some information on them that may be of
> > interest to some of you. If you want me to scan the page
> > and send you a copy, just request it via email and I will do
> > it.
> >
> > 1. There was discussion about whether or not it was
> > appropriate to wrap a guy wire around a tower leg or whether
> > you must always use guy attachment hardware. I have a page
> > from a 1977 Rohn catalog showing the proper way to wrap a
> > guy wire around a tower leg. Request document 2536.
> >
> > 2. There was some discussion about whether Rohn recommends
> > the use of Preform Guy Grips. Of course, they do. There
> > was also some question about Rohn's position on using End
> > Sleeves with Big Grips. They say End Sleeves MUST be used
> > with all guy grips. This information can be found on Page
> > HA-2 of the very latest Rohn Consumer Catalog. Request
> > document 2537.
> >
> > 3. There is some very interesting new information about the
> > use of 25, 45, and 55 towers in TVRO (Television Receive
> > Only) applications in the latest Rohn Consumer Catalog. The
> > guying digrams show guys at a much steeper angle than any I
> > have seen before on any Rohn diagram and with a much larger
> > Effective Projected Area on the top than I have seen
> > before. (48.9 square feet at 70 mph on 25G, for example).
> > This is a TVRO application, remember, and the load is
> > expected to be a 6 foot diameter dish and not a long boom
> > Yagi. Still, the information is interesting because it is
> > so different than any I have seen before from Rohn. Use
> > caution when applying this to ham antennas. Better yet, use
> > a PE to apply it for you. For 25G TVRO Guying Diagram and
> > Parts List, order documents 2538a and 2538b.
> >
> > 4. For 45G TVRO Guying Diagram and Parts List, order
> > documents 2539a and 2539b. (87 square feet at 70 mph, 8
> > foot dish)
> >
> > 5. For 55G TVRO Guying Diagram and Parts List, order
> > documents 2540a and 2540b. (94 square feet at 70 mph, 10
> > foot dish)
> >
> > Are there any other Rohn documents or drawings you would
> > find useful that I can scan and send you? I hope I can
> > handle the volume . . .
> >
> > Stan w7ni@teleport.com
> >
> >
> >
> > --
> > FAQ on WWW: http://www.contesting.com/FAQ/towertalk
> > Submissions: towertalk@contesting.com
> > Administrative requests: towertalk-REQUEST@contesting.com
> > Problems: owner-towertalk@contesting.com
> >
>
> ------------------------------
>
> Date: Thu, 10 Aug 2000 22:04:58 -0500
> From: "Mike Foerster" <mike.foerster@home.com>
> Subject: Re: [TowerTalk] Tower Base Technology
>
> Dave (and others),
>
> Thanks for the info. I really like the idea of putting the rotor down
near
> the base!! I've heard of guys that have had to replace rotors from time
to
> time.
>
> What size black pipe did you use and where did you find it?
>
> I have planned on putting the "big block" of concrete at the base, but one
> of my jobs at work is to find a better way to do most everything that we
do
> (i.e. Continuous Improvement...). I was hoping that someone had a
better
> idea.
>
> Yes, I know that the TH11DX exceeds the 10 foot, so does most antennas.
But
> this one was up for quite a while and considering that the tower is
spec'ed
> at 18 -20 sq. ft (at 3 ft above the tower) and this antenna is only 12 sq.
> ft, and will be mounted just above the tower, it should hold out OK for
> another few years. It did fairly well for 6 years. Would have been
better
> if the guy would have done the maintenance that he should have.
>
> Anyway, thanks for your comments.
>
> Mike
>
>
> - ----- Original Message -----
> From: wa3gin@pop.erols.com <wa3gin@pop.mail.rcn.net>
> To: <mike.foerster@home.com>
> Sent: Thursday, August 10, 2000 9:30 PM
> Subject: Re: [TowerTalk] Tower Base Technology
>
>
> HI,
>
> I have had three of these towers. Going to put up one next month. The
> secret to solving the twist problem is to run black pipe from the base all
> the way up to the top and up for the mast. You mount the rotor on the
> concrete base where it is easy to maintain. Easy to lock down in storms,
> easy to remove and replace , etc. In this scenario there is no twist
moment
> on the tower. The pipe and rotor take all of it as they are designed to
do.
> All the tower does is stand up. By removing the twisting you make the
> installation straight forward and the tower will be up longer than you
will
> be alive, HAHA
> On the concrete base you have to remember the vendor has to prescribe
> something that in general works in almost every condition, the worst case
> scenario. Contact your local PE or Civil Eng. for guidance on what would
> work for you...also remember that the guys that built this tower factored
in
> for numb nuts that would over load the tower with twice the windload.
> Typically I've seen installations where 4x4x4ft and 4x4x3ft deeep have
been
> used successfully.
>
> Good luck,
> dave
>
>
>
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> ------------------------------
>
> End of Tower Talk Digest V3 #305
> ********************************
>
>
> --
> FAQ on WWW: http://www.contesting.com/FAQ/towertalk
> Submissions: towertalk@contesting.com
> Administrative requests: towertalk-digest-REQUEST@contesting.com
> Problems: owner-towertalk-digest@contesting.com
>
--
FAQ on WWW: http://www.contesting.com/FAQ/towertalk
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Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com