[TowerTalk] Choice of aluminum

[Rudy Bakalov]

Jorge,

This is a great question that has been on my mind for a while. I was very tempted to try to model it, but never found the time to do so. I also thought that all I care about is the CW/RTTY portion of 80m.

That said, I decided to see what DX Engineering offers on their site for 80 m. Two very interesting observations from the 80m vertical installation manual:

1) they use very small size tubing, not even close to what I am considering (my current 40m vertical uses better tubing!!!)

2) they claim a very wide bandwidth

So if their 80m verticals are half as good as they claim, the much beefier size tubing I am considering should do very well.

Rudy N2WQ


________________________________
 From: Jorge Diez - CX6VM <cx6vm.jorge at gmail.com>
To: 'Rudy Bakalov' <r_bakalov at yahoo.com>; TexasRF at aol.com; towertalk at contesting.com 
Sent: Saturday, October 13, 2012 7:36 PM
Subject: RE: [TowerTalk] Choice of aluminum
 
Hello Rudy

What´s the bandwidth of this verticals compare with towers?

73,
Jorge
CX6VM/CW5W

-----Mensaje original-----
De: TowerTalk [mailto:towertalk-bounces at contesting.com] En nombre de Rudy
Bakalov
Enviado el: sábado, 13 de octubre de 2012 21:04
Para: TexasRF at aol.com; towertalk at contesting.com
Asunto: Re: [TowerTalk] Choice of aluminum

Gerald,

Thanks for the comprehensive answer. I didn't realize that 6061-T6 is more
expensive than 6063 as I was looking online prices in chunks of 12 and 24'.

Just for kicks I prices a 4-Square set of verticals made of 24' sections of
3", 2.5", and 2.0", 0.25" wall thickness. $2,300 delivered for the set.
Doesn't look that bad compared to dealing with towers and tower crews.


Rudy N2WQ


________________________________
From: "TexasRF at aol.com" <TexasRF at aol.com>
To: r_bakalov at yahoo.com; towertalk at contesting.com 
Sent: Saturday, October 13, 2012 6:36 PM
Subject: Re: [TowerTalk] Choice of aluminum


Hi Rudy, 6061-T6 aluminum has a yield strength rating the same as 6063-T832 
that is sold by Texas Towers and others.
 
The 6061-T6 costs more than 6063-T832 because of the extra 
heating/quenching steps needed to reach the rated yield strength. 6063-T832 
reaches the rated yield strength by work hardening the material in the
drawing 
process.
 
If you want a self supporting vertical, then you would need to go through 
the same process as designing a 80 meter beam element with most of the
material 
weight left out of the calculations. Just as a guess I would expect the
bottom 
section to be about 4" diameter with a .25" wall.
 
This is not a trivial structure! Please proceed with caution!
 
If you want a guyed vertical, there are a number of them that have been on 
the air long enough to think about duplicating one. W5UN is one that comes
to 
mind.
 
73,
Gerald K5GW
 
 
 
 
 
In a message dated 10/13/2012 4:09:30 P.M. Central Daylight Time, 
r_bakalov at yahoo.com writes:
I was  wondering if anyone can help me select the right material for
full-size 80m  verticals. My questions are as follows:
>
>1) metalsupermarkets.com offers 
  6061-T6 aluminum, but not T8. Is there a difference between T6 and T8 for
my 
  purpose?
>2) Should go for the 0.125 or 0.065 wall thickness?
>3) Is 1" 
  tubing OK for the topmost segment? Too stiff for the wind at 70'? Not
strong 
  enough?
>
>
>I am aware that many ham stores offer 6061-T8 tubing, but I 
  do want to buy it local in VE3, close to my QTH, in 12' lengths (instead
of 
  6') and avoid shipping complications due to length or clearing 
  customs.
>
>73 Rudy 
  N2WQ
>_______________________________________________
>
>
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>TowerTalk 
  mailing 
  list
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