Please don't laugh electronically switched beam
Pushing 40 years ago my father had a 2 element vertical beam for CB (that's the don't laugh part) it actually had 3 elements in a triangle and was electrically switched across 2 for some directivity. It seemed to work pretty good he once talked to France on it obviously not quite legally. Did or does anyone make a similar one for ham use? No rotor, no hassle and just a small box on his workbench, it would seem like something that would be handy today. I thought at the time it was much handier than when his one armed friend decided to put up a tower and beam in fact that was the only thing he had a tough time with, he rode a motorcycle and didn't mind wheelies and he would occasionally take me for a pretty wild ride in his Porsche engined Beetle he was an excellent knee steerer. Of course my father used to sew his fingertips together for our amusement, a different world but I digress. Thanks!
I'll be darned under the post CB Antenna there it is a Antenna Specialists Super Scanner CB Antenna!
Yeah a friend of mine had one of those... "Super Scanner" right?
Originally Posted by KB8TVN
I think it might be electrically switched to have two reflectors and one driven, for what it's worth.
If I have the design of the CB antenna right, it's very similar to some different parasitic sloping dipole arrays that have been pretty common on the lower bands:
Did or does anyone make a similar one for ham use? No rotor, no hassle and just a small box on his workbench, it would seem like something that would be handy today.
Sounds like phased vertical array with switching to control the direction it was pointing. With three of them you could get most of the compass. They have a bit of gain and fair front to back ratio. I had one on 20 meters when I lived in San Antonio and it worked quite well - at only 16' tall and ground mounted, it did not "STAND OUT" in the residential area where I lived.
Antenna Specialists MS-119, Super Scanner antenna.
These have been modified for 10-meter, amateur radio usage.
The Super Scanner antenna was a compromise (it had nulls), and radio amateurs primarily used Tri-band (20,15,10) meter beams.
Trapped designs and CDE TV rotators were adopted in 1950s (QST articles) ... and became the preferred antenna installation since.
The theory and practical usage of Phasing of Vertical Antennas has existed since 1920s and 1930s ...
commercially with Medium Wave, AM broadcasting (550 kHz - 1700 kHz).
At these long wavelengths, a 1/4-wavelength vertical (600 kHz) is 125 meters (410 Feet) in height.
In these instances the radio engineer for an AM broadcasting station (600 kHz on dial) used 410 foot towers, with insulators at base, as the driven vertical radiator.
The University of Iowa used 3 self supporting towers (N-S Alignment, circa 1930s) for their AM broadcasting station, until a tornado 15 years ago forced it's replacement.
As the frequency INCREASES ... the wavelengths decreases, become SHORTER ---
Inverse relationship (core radio theory required for FCC licensee).
The principles and usage of phased verticals are easier for the part-time radio amateur or hobbyist
to DIY Build or Fabricate --- at wavelengths of 20 meters and shorter (17, 15, 12, 10, 6).
Last edited by W9GB; 05-26-2012 at 01:29 PM.
We keep moving forward, opening new doors, and doing new things, because we're curious and curiosity keeps leading us down new paths. -- Walt Disney
The police monitor group back in the mid 70's had one of those on the bank building in Fort Worth. It seemed to work pretty well and was somewhat directional. It had a control box to remotely switch the direction.