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KT8K
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Posts: 1490




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« on: January 15, 2003, 10:12:44 AM »

Pardon me for foggy memory, but back in the 70's Antenna Specialists made a CB antenna called the Super Scanner, which was comprised of three closely-spaced vertical dipoles in a triangle with a relay switch box.  They claimed it performed like a 3 element beam and the direction was electrically controlled from a switch box in the shack.  I assumed they were switching a quarter wavelength delay line to one of the three elements, but I haven't been able to figure out how their relay must work.  I still know where at least one of those antennas is , and I hope to get my hands on it, but chance of that may be slim (it belongs to a huge corporation and finding the right person to talk to is  beyond difficult).  Web searches have turned up no information on the antenna or the phasing system design.  Can anyone help?  I'd like to build a setup like it for an HF band.
tnx es 73 de kt8k - Tim
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RobertKoernerExAE7G
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Posts: 1435




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« Reply #1 on: January 15, 2003, 11:57:15 AM »

ON4UN's book, "Low Band DXing" goes into great detail about phasing verticals, offering many types of phasing networks.  Included are 2, 3, and 4 element phased verticals.

The last issue, 3rd?, has the best section about radials.

If I remember correctly, the antenna you are looking at functions as driven element and two reflectors.

Have FUN
Bob
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WB6BYU
Member

Posts: 17050




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« Reply #2 on: January 15, 2003, 03:46:34 PM »

I suspect the length of feedline from each element to
the switchbox had a length so that when the end was
open it would add just enough inductance to the center
of each element to make it act like a reflector.  The
coax would then be connected through one of these
pieces of cable to the desired driven element, while
the unconnected ones acted as a pair of reflectors.

You probably could do the same thing using a shorting
switch, choosing a feedline length so it gave the
needed inductive reactance when it was shorted instead
of open.  Otherwise you probably need to switch BOTH
sides of the coax cable.
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KZ1X
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Posts: 3330




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« Reply #3 on: January 15, 2003, 04:39:01 PM »

You mean, like this?

http://www.comteksystems.com/

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AD7DB
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Posts: 413


WWW

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« Reply #4 on: January 15, 2003, 05:22:48 PM »

I know what you're after. 3 vertical antennas in an equalateral triangle. Uses two of them at any given time, and the antenna pattern is bidirectional. Thus, by switching them around using relays you get it to point 3 different ways and basically cover 6 paths.  I know that QST had an article on how to do this in the 1950's because I have those CDROMs and I saw it there. If you want I'll look it up. Your nearby library may even have these back issues so you can get the details.
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AB8IG
Member

Posts: 131




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« Reply #5 on: January 15, 2003, 06:08:45 PM »

I had one of those about 30 years ago and my memory is a little foggy also. The control box had a four position rotary switch. Three of the positions lit a corresponding pilot lamp on the box indicating which element was active (directional mode). The fourth position lit all three lamps simultaneously (omnidirectional mode). When one dipole was active, the two passive elements acted as reflectors. In omni mode, all three were active. The relay box was mounted on the 'spider' holding the three  dipoles. The relay box was connected to the control box with 4 conductor TV style rotator wire. That would seem to imply that there were three relays inside the relay box.
I used to have a manual but chances of finding it now are slim to none.

Jim
 
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