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Re: [TowerTalk] phasing multiband verticals

To: "'Dick Williams'" <k8ztt@mho.com>, <towertalk@contesting.com>
Subject: Re: [TowerTalk] phasing multiband verticals
From: "Bill Axelrod" <bill@axelrods.org>
Date: Tue, 10 Mar 2009 08:40:33 -0500
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Dick,

     I am in the process of installing a pair of 40 meter verticals and am
awaiting delivery of a COMTEK PVS-2 for phasing.  I have one antenna
installed and about to plant the second.

     In your email you state that 49' separation on 40 meters is the best
spacing. Very timely to hear that.  Why is 49 ft better than 1/4 or 1/2 wave
spacing?  What patterns can one expect from that spacing?

Thanks and 73...   Bill ND9E



----- Original Message -----
From: Dick Williams
To: towertalk@contesting.com
Sent: Tuesday, March 10, 2009 2:32
Subject: Re: [TowerTalk] phasing multiband verticals


Jamie,

I have two Force 12 160 mtr verticals that I have spaced at 1/2 wave and am
using the ComTek PVS-2 system.  It uses a three wire configuration to switch
three directions.  Before I bought that, I was using a home brew phasing
system that gave me either an end fire or cross fire pattern (feeding in
phase or 180 out).  The nice thing about the ComTek is it uses a 2.25:1 UNUN
for the in phase matching and an electric 90 degree phase shift to give gain
for either direction of the end fire.

Actually the best spacing for their system on 40M is 49 ft (more than a
quarter but less than a half).   I use 1/2 because that gives me better
cross fire gain at the expense of some end fire gain; and my verticals are
on a NW/SE line (NE/SW would be better, but that wouldn't work at my QTH).

I have mono band antennas for all the bands and only run one coax and two
rotor cables into the shack.  I designed and built a remote switching system
that uses +, -, 0, and AC down the coax along with a hard wire to the first
relay box that I use the same voltages to swith the one coax out to the
first four runs to additional switch boxes.  The only reason I have two
rotor lines is I needed a seperate one for the Orion 2800.  All the other
rotors are Hy-Gain and I remote switch them so I only have one CDE (Hy Gain)
rotor box in the shack.

You might look into control voltage down the coax;  and if you run a single
wire out to a coax switch box (like the Ameritron RCS-4) you can switch 16
antennas with four additional boxes.   I have three of the RCS-4s along with
a couple of MFJ-4712's to do all my switching.  I called them up and bought
just the relay boxes, and then modified them as necessary to work as I
needed them to.

I will say that I have been very pleased with the ComTek PVS-2 on 160M.

Good luck

Dick K8ZTT

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