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
In a message dated 12/19/2012 9:09:41 A.M. Central Standard Time,
w3ea@hotmail.com writes:
Hi Roger
The small 24' BX style towers are not the failure Point. it's the 44'
stinger that's the area of failure !
Another friend who's of the DX- Expedition type suggested I opt for the
tapered fiberglass poles. !
Still trying to model or see why the insulated stinger at the top of the
tower has such a remarkable effect ?
Wayne W3EA
( I am sorry for the post, I am not able to get word wraparound to
function on this reflector ! )
> From: K8RI-on-TowerTalk@tm.net
> To: towertalk@contesting.com
> Date: Wed, 19 Dec 2012 08:52:36 -0500
> Subject: Re: [TowerTalk] Hi Gain Hi Tower ??
>
>
> Why not guy them with phillystran or poly rope?
>
> 73
>
> Roger K8RI
>
> ----------------------------------------
> 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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