Fw: Re[2]: [TowerTalk] The last aluminum mast comment

[Ed Jensen]

Hi Hank,

You wrote:

>     Steve:
>
>     Your calculations are a little off. Please note the following:
>     Discl      10      2.7     25      675             8100

These were my calculations Hank, not Steve's.  And you're right (gack), I
left out the wind pressure from the 40m dipole calc (mea culpa).  Revised
numbers are:

Antenna      area (sq ft)      Hgt (ft)    bending moment(ft#)
 TH7               9.4                .5             118
 WARC 2/2     3.1             5              390
Disc1          2.7                 10            675
 214FM        1.7                 12            516
 mast             1.2                  6 (avg)     180

Total                                            1879 (over allowable 1628)

OK, so we would have to use closer spacing (I know, it's getting a little
close
but the point is that it can work (if I just do the math right)),

Put the TH7 right at the top of the tower, the WARC 2/2 at 4 ft,  the Disc1
at 8 ft and the 214FM at 10ft with 10 ft of mast sticking out of the tower.
Then the loads are 0, 310, 540, 425, 150 for total of 1425 ft#, within
the allowable stress of the mast.

BTW, the excellent article by Stan on Tom's home page clearly explains the
techniques so the the methods are readily available to anyone.

73, Ed

Ed Jensen, K5ED, El Paso, TX, k5ed@dzn.com



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