Does anyone know what the resonant freq. is of the 30ft of 3" tubing without
the addition of a top hat?
Thanks,
dave
wa3gin
----- Original Message -----
From: "Rick Karlquist" <richard@karlquist.com>
To: "Red Haines" <redhaines@acegroup.cc>
Cc: "TowerTalk" <towertalk@contesting.com>; <rlvz@aol.com>
Sent: Saturday, December 01, 2007 2:34 PM
Subject: Re: [TowerTalk] Irrigation pipe vertical
30 ft of 3 inch 0.050 inch wall (the standard) weights 16.5 lbs.
It is very easy to handle, but you need the bottom anchored to
push it up (you can't stand it on its end "free hand" unless
you are very strong).
Regarding the base. This depends on the soil and the wind.
At my QTH, during the winter, we can rains that turn the pure
clay soil into a consistency of peanut butter, accompanied
by winds well over 50 MPH. This is guaranteed to make a
4x4 sunk into the ground 3 ft tip over when holding up a 30
ft vertical. Of course YMMV. I decided it was a lot easier
to put light guy ropes up than make a self supporting base.
30 ft of 3 inch is good for something like 80 MPH winds according
to some rough calculations I made.
Rick N6RK
Red Haines wrote:
> Hi, Dick;
>
> You ask a very pertinent question, especially for those who might use
> irrigation pipe for portable antennas. The answer is no, aluminum
> irrigation pipe is lightweight. I estimate that the 30', 3" pipe weighs
> less than 30 lb. I can easily carry a 30' 2" pipe telescoped inside a
> 30' 3" pipe and I can erect the extended pair by myself, if the bottom
> end is anchored by one of the bases that I put them on. This is not a
> demonstration of my strength; I'm 74 years old and weigh about 145 lb.
>
> 7e de Red, WOØW
>
> RLVZ@aol.com wrote:
>
>> Hi!
>>
>> Isn't irragation pipe real heavy? I am thinking it would take a
>> serious base.
>>
>> 73,
>> Dick- K9OM
>>
>>
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