Joe...I was wrong in my post. My verticals are 1/2 wave apart on 80m, which is
the same as 1/4 wave on 160.
After writing my message, I went back and added the 66' for clarity, and should
have been 132'
You are correct, using RG8X with velocity factor of .78, the phasing lines are
about 53.5' and there are two of them, making them a too short to reach the 132'
I really DO have 80m verticals that are 1/2 wave apart. (incidentally I share
the radial fields with the 160m antennas which are 1/4 wave apart)
So the question remains, how to properly feed phased verticals that are
physically 1/2 wave apart
73
Dale
________________________________
From: "Joe Subich, W4TV" <lists@subich.com>
To: topband@contesting.com
Sent: Saturday, November 17, 2012 7:18 PM
Subject: Re: Topband: phasing line lengths for phased verticals
1. for 80m phased verticals that are 1/2 wave apart (66 feet),
That is 1/4 wave separation - not half-wave. One half wave on 80 is
roughly 139 feet (984/3.55/2 = 138.6 feet).
Since you are using 1/4 wave spacing and a PVS-2 (which is a quadrature
device if I remember correctly), two /14 wave cables (about 54' each
when the velocity factor for foam is included) should *easily* reach
the midpoint of the array.
73,
... Joe, W4TV
On 11/17/2012 6:56 PM, DALE LONG wrote:
Until recently, I had phased verticals on both 80m and 160m and lots of
beverages. (this was in a woods, and not my property) Then the loggers came
and destroyed all.
In addition to the antennas, the phasing lines were torn up, and broken and
needed replacement. For 160m I use the Christman method with .71 and .84
wavelength lines. For 80m I use a Comtek PVS-2 controller.
In replacing the 80m phasing lines today I made a stupid mistake, I dont know
what I was thinking, but I carefully measured and soldered two identical 1/4
wave lengths of new coax. I tested them on my AIM 4170 and they were nearly
identical, exactly on the design frequency. Then I went to install them and
guess what...of course they were too short. I have worked with phased
verticals before and I know that you often need to use 3/4 wave phasing lines,
but I was too intent on measuring and soldering and making the repairs.
So now I have two questions.
1. for 80m phased verticals that are 1/2 wave apart (66 feet), what will be the
pattern? It's not the same as 1/4 wave spacing, so what really is happening?
2. what is the best length of phasing line to use. Should I use 3/4 wave
phasing lines? Should I avoid using 1/2 wave phasing lines?
Thanks
Dale - N3BNA
_______________________________________________
Topband reflector - topband@contesting.com
_______________________________________________
Topband reflector - topband@contesting.com
_______________________________________________
Topband reflector - topband@contesting.com