[TowerTalk] Crankup Tower for DB-36

[Gary Saboe]

John, your same question was asked about a year ago on this list regarding what tower to use for a DB-36.  I have an UST HDX-772MDPL (spec: max load 700lbs, 70sq ft @ 70mph) with a SteppIR MonstIR and F12 Sigma-280 Magnum mounted, so yes UST does have additional special order towers available--just not listed in their catalog or on their website. Mine is based on their HDX-5106 design, minus the top two sections.  Call UST and talk with them regarding your needs.

Gary NØGS

-----Original Message-----
From: towertalk-bounces at contesting.com [mailto:towertalk-bounces at contesting.com] On Behalf Of John Kuklewicz N7ZN
Sent: Friday, January 27, 2012 3:54 PM
To: Tower Talk List
Subject: [TowerTalk] Crankup Tower for DB-36

Well, after many years of wishing, it looks like 2012 will be the year I finally get a tower and yagi added to my station. After many years with multi-band verticals and relatively low wires this is a much anticipated enhancement. More than likely with will be the one and only tower I will be able to install.

I do not have any experience with towers, and would value your inputs on my thinking below.

I would very much like to install a Steppir DB-36 on a tower of at least
70 feet. I know, higher would be better, but the next increment in height seems to entail a disproportionate increase in cost. After all these years, I really would like to have gain antennas on 40 and 30 meters. Per Steppir, the DB36 is 17.5 sq ft, 160 lbs.

After a lot of soul searching, I have to admit that I am in no shape to be climbing towers, and this is not likely to change. And there is not a strong local climbing ham population to assist.

So, a crankup/tiltover tower (with NN4ZZ tiltplate) seems to be the only solution. The only towers that look even close are the US Tower HDX-572 or the Tashjian DX-70.

I am fortunate to live in a rural area with no zoning or permitting requirements. I can put up any foolish thing I want. <grin>

Today I was able to obtain an engineering analysis for the HDX-572 and was disappointed to learn that the Windload is limited to 14.1 sq ft (exposure B, 90 mph 3 second gust, 76mph fastest mile.)

The Tashjian DX-70 shows a spec of 47 sq ft (85 mph 3 second gust). 
Clearly this will be adequate (if not somewhat over designed - which is not a bad thing). Of course, the DX-70 initial quote I have about $1K more than the HDX-572. IT would certainly seem that the increased capacity is worth the greater initial expense.

Can anyone help by contributing their experience with a DB36 (or similar large antennas) on a crankup in the 70 foot (or taller) class?

Many thanks and 73;

John N7ZN


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