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Old May 13th 13, 01:36 AM posted to rec.radio.amateur.antenna
Ralph Mowery Ralph Mowery is offline
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First recorded activity by RadioBanter: Jul 2006
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"Jeff Liebermann" wrote in message
...
Yep. It was called a "co-phasing harness". Basically, the same thing
as a Wilkinson power divider. The original purpose was to deal with
the problem that the truckers were having with mounting antennas on
their big rigs. The antenna could not be mounted on top of the
tractor or trailer because the weight scale operators did not like
antennas smashing into the overhead clearance gauges. However, one
antenna on the side of the tractor didn't work very well because it
blocked signals on the other side. Two antennas were just fine. The
only problem was that while in receive, there was little loss from
either antenna, in transmit, the power was split equally between
sides. To compensate, doubling the transmit power was deemed
necessary. It worked.

At the time 1973(?), I was working on an ill fated CB related project
that would eventually have Antenna Specialists' name on it. I
discussed the co-phasing harness problem with one of their engineers.
He mumbled something about it being a great way to double antenna
sales. The rest you can guess.


During that period of time I repaired things for the CBers to pick up some
extra spending money. I was thinking there was a mobile antenna system that
you mounted two antennas and had a switch box that phased them for differant
directions. Don't believe it worked too well as the antennas were usually
too close together. The the base station 'scanner' antenna was devoloped
using 3 verticals in a triangle patern several feet apart. Seemed to work
ok for what it was.

During that period of time, I think Antenna Specialists' made up much of the
CB antenna sales.

Only double the power,, many of the ones I knew ran 50 to 100 watts in the
mobiles back in the 70's . During those years you could sell almost
anything to the CB. Much like for the last number of years you can sell to
the audio/hifi people. Best scam I know of is the wire going from the hifi
to the wall socket. For about $ 120 you get 6 to 8 feet of 'special wire'
Even if it was special that would not account for the wire going from the
outlet to the breaker box and then to th epole transformer..