It should not be that difficult to design a 44' stinger that will hold up
to the elements. I had a homebrew 54' freestanding vertical that held up
to Aruba's winds for a decade. The stinger needs to be tapered and start
with a heave base as Gerald suggested.
John KK9A / P40A
To: w3ea@hotmail.com, towertalk@contesting.com
Subject:Re: [TowerTalk] Hi Gain Hi-Towers
From: TexasRF@aol.com
Date: Wed, 19 Dec 2012 10:26:46 -0500 (EST)
Wayne, have you done a stress analysis of the stinger? You should be
able
to use one of the yagi stress programs to do that.
If you think about it, your 44ft stinger is similar to one half of an
88ft
long yagi element. That is not a trivial size; quite a bit longer than a
full sized 40m element for example.
It is not unusual to see a full sized 40m element that is 2 to 2.5" OD
at
the center and 1/4" wall thickness.
Since the stinger is much closer to the ground than a typical 40m beam,
there will be somewhat less wind exposure. It seems logical that there
would
be no need for wind survival greater than 70 mph but it depends greatly
on
how exposed the stinger is to the wind. A few trees or buildings in the
vicinity would help with wind exposure. Sitting at the top of a nice
hill and
in the clear, then full exposure should be expected.
A possible solution is adding some guys to the stinger. Some 1200 pound
rated Phillystran would serve well for that.
Hope this helps resolve your problem.
73,
Gerald K5GW
>
> ----------------------------------------
> From: "Wayne Kline" <w3ea@hotmail.com>
> Sent: Sunday, December 16, 2012 9:28 PM
> To: "towertalk@contesting.com" <towertalk@contesting.com>
> Subject: [TowerTalk] Hi Gain Hi Tower ??
>
> Hi fellow Tower Talkers.. . I built a 75/80 meter Four Sq, antenna
system
> many years ago. It was feed with an original DX eng. ( not the new Dx
eng
> co.) quadature. The Hi Gain Hi towers were stripped of everything
and a
> center stinger was built and the system was resonantat 3.625 MHZ
and
> the power dump at 3.500 was 70 watts and at 3.825 was 100 watts. I
used
> the two insulators at the two stinger vertical element with a 14ga
wire
> attached at it's bottom and travel down the inside of the 24ft base
tower
> attaching at the feed point. There are 108 evenly spaced 1/4 radials
under
> each antenna, with silver soldered connections at there interesting
8ga
> copper X and 9- 8 ft 5/8" ground rods. One at each tower base, one
at
> the control box in the center of the array and 4 at the end of the
> centered X wire.I had a few 80 meter ops who felt that because I
insulated
> the top 38' stinger at the top of the tower resulting in a Shorter
over
> hight antenna was a compromise. So I
> got in touch with tim K3LR knowing he also had a 75/80 meter 4 SQ mad
out
> of Hi-Gain Hi Towers, He sent me a rough dimension of his stinger out
the
> top of his Hi-Tower. I un insulated the stinger and built my
elements
> and achieved resonance with an additional 9ft height.Well it seemed
My
WX
> in eastern PA did not like the 48' stinger and I would loose one at
almost
> every Nor'easter Storm. SO I am thinking of going back to the
> original configuration with insulated top 2" tuber and the 14 ga
wire
down
> the center of the tower to the base. Thought's out there Just
kicking
> around ideas ? Wayne W3EA
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