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[TowerTalk] MA-550 Tubular Tower

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Subject: [TowerTalk] MA-550 Tubular Tower
From: (Ralph Danyluk)
Date: Thu Aug 7 13:26:02 2003
Hi Rick,

Good question -

For me small yagi means Boom Length < 15 feet and wind load < 10 sq. ft. and
weight < 30 lbs..
This would include Cushcraft MA5B, TGM,  Force-12 C3 series HF yagis, and
probably most VHF yagis.
Of course small is a relative term.

Wind load area and weight are the important numbers.
According to the US Tower web site, the MA-550 wind load area and weight
ratings are:

70 MPH Winds -- 9 sq. feet; 65 lbs.
50 MPH Winds -- 22 sq feet; 100 lbs

My understanding is that these figures apply for a fully extended tower.
So based on these figures the MA-550 will support a larger yagi, especially
if cranked down in higher winds.
Rotating from the top or base, eve/roof anchoring, and guying will also
change things.

Hope this helps.
Ralph - VE7AOP

-----Original Message-----
From: Rick Kniss []
Sent: Tuesday, August 05, 2003 7:51 AM
To: 'Ralph Danyluk'
Subject: RE: [TowerTalk] MA-550 Tubular Tower


I wonder if you could you could give me some more insight as to what
people meant by "small yagis". For example, would you guess that a 36ft
boom, 5 ele Force 12, 20 meter yagi would be ok. Especially if one was
willing to crank the tower down in high winds.
Thanks in advance for your reply.
Rick, W6MCA

-----Original Message-----
[] On Behalf Of Ralph Danyluk
Sent: Monday, August 04, 2003 8:54 PM
Subject: RE: [TowerTalk] MA-550 Tubular Tower

Hello Steve,

All the responses were favorable.  In summary:

- There is some sway, but tolerable with small yagis.
- Base rotor is better then top rotator.
- Rotating at base precludes roof/eve bracketing.
- US Towers is a good company with which to do business.
- Not as stiff as a lattice tower - understandably - interesting calc
Rick, N6RK, for stiffness coefficient as function of diameter.
- Cable replacement if required for disassembly can get tricky.
- A couple of good links and photos were provided - Jim, KH7M
- Skip, KJ6Y, has installed many MA tubular towers as part of his

For an urban dweller like me looking for a tower with a small foot print
low visibility, this seems to be a good choice.

Ralph - VE7AOP

-----Original Message-----
From: []
Sent: Friday, August 01, 2003 6:11 PM
Subject: Re: [TowerTalk] MA-550 Tubular Tower

In a message dated 8/1/03 2:23:17 PM Pacific Daylight Time, writes:

> I found it very valuable.

    So...what did you find out? I'm sure 1200 other TowerTalkians would
interested in the comments.

Steve      K7LXC


See:  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.

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