The phasing system takes care of the bandwidth problem on 4-squares. Just
be sure to tune them per manufacturer's instructions for the phasing box and
they should be fine.
David Robbins K1TTT
e-mail: mailto:k1ttt@arrl.net
web: http://wiki.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://k1ttt.net
-----Original Message-----
From: Rudy Bakalov [mailto:r_bakalov@yahoo.com]
Sent: Sunday, October 14, 2012 00:15
To: Jorge Diez - CX6VM; towertalk@contesting.com
Subject: Re: [TowerTalk] Choice of aluminum
Jorge,
Before you give up on the vertical idea and spend your money on building
towers, do take a look at
http://static.dxengineering.com/global/images/instructions/dxe-7580fsva-1-re
v1b.pdf and
http://static.dxengineering.com/global/images/instructions/dxe-7580fsva-2-re
v4a.pdf for the "heavy duty" version. The manual claims "Guying is usually
at 2 levels. Bandwidth is outstanding, a 456 to 528 kHz 2:1 bandwidth
depending on your radial field."
Also, are you going to use a single vertical or a 4-square system? I am
building a 4SQ so the question of bandwidth gets even more complicated due
to the 75 Ohm phasing lines.
Rudy N2WQ
________________________________
From: Jorge Diez - CX6VM <cx6vm.jorge@gmail.com>
To: 'Rudy Bakalov' <r_bakalov@yahoo.com>; towertalk@contesting.com
Sent: Saturday, October 13, 2012 8:02 PM
Subject: RE: [TowerTalk] Choice of aluminum
Hi Rudy,
You are lucky!, I am considering something for CW/SSB J
There´s some commercials self supporting towers. Also a Rohn 25 is good for
a guyed tower. My problem is shipment cost and handling.
So looking for instructions about how to build one J
73,
Jorge
CX6VM/CW5W
De:Rudy Bakalov [mailto:r_bakalov@yahoo.com]
Enviado el: sábado, 13 de octubre de 2012 21:46
Para: Jorge Diez - CX6VM; TexasRF@aol.com; towertalk@contesting.com
Asunto: Re: [TowerTalk] Choice of aluminum
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@gmail.com>
To: 'Rudy Bakalov' <r_bakalov@yahoo.com>; TexasRF@aol.com;
towertalk@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@contesting.com] En nombre de Rudy
Bakalov
Enviado el: sábado, 13 de octubre de 2012 21:04
Para: TexasRF@aol.com; towertalk@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@aol.com" <TexasRF@aol.com>
To: r_bakalov@yahoo.com; towertalk@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@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
>_______________________________________________
>
>
>
>_______________________________________________
>TowerTalk
mailing
list
>TowerTalk@contesting.com
>http://lists.contesting.com/mailman/listinfo/towertalk
>
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