https://chicago.craigslist.org/chc/ele/d/west-chicago-avanti-av-170-sigma-ii-8/7418552240.html
Not mine I just happen to see this.
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Avanti Sigma II for sale
- Thread starter w9cll
- Start date
https://chicago.craigslist.org/chc/ele/d/west-chicago-avanti-av-170-sigma-ii-8/7418552240.html
Not mine I just happen to see this.
An AV-170 Sigma II antenna recently sold for $300.00 on eBay.
https://chicago.craigslist.org/chc/ele/d/west-chicago-avanti-av-170-sigma-ii-8/7418552240.html
Not mine I just happen to see this.
Amazing that at one time Avanti was prosperous enough to sponsor Roland Leong's Hawaiian funny car......
They were big. They weren't far from me and visited them a couple of times.
Avanti had a patent for the through-the-glass windshield-mount antenna. Sold one built for CB. Had a small matching box at the end of the coax. Got glued to the inside of the windshield. Placement had to be the exact correct distance from the metal frame. Too far or too close and it wouldn't tune correctly. The metal antenna "foot" glued to the outside of the windshield, lined up with the matching box. The RF passed through the capacitor made by the metal foot on the matching box, the metal foot on the whip mount and the windshield glass as the dielectric.
The CB whip was fiberglass, and not quite 2 feet long. Was wound to act as if it were a half-wavelength long.
End-feeding a half-wave radiator gets you a really high impedance. High enough that the windshield-glass capacitor would work at 27 MHz.
More or less. The "Astro-Phantom" mobile CB antenna was covered by a patent that protected this through-glass feed point.
A few years go by, and Antenna Specialist wants to be dominant supplying antennas for mobile cell phones. It was an explosive-growth market, and they bought the whole Avanti company, just to get that patent.
Or so the story goes. The Avanti CB products were produced by Antenna Specialists for a while, and then got totally discontinued.
Oh, and the Astro-Phantom was famous for one thing. Flying off the windshield at high speed, never to be seen again. They never did get the glue quite right.
73
The CB whip was fiberglass, and not quite 2 feet long. Was wound to act as if it were a half-wavelength long.
End-feeding a half-wave radiator gets you a really high impedance. High enough that the windshield-glass capacitor would work at 27 MHz.
More or less. The "Astro-Phantom" mobile CB antenna was covered by a patent that protected this through-glass feed point.
A few years go by, and Antenna Specialist wants to be dominant supplying antennas for mobile cell phones. It was an explosive-growth market, and they bought the whole Avanti company, just to get that patent.
Or so the story goes. The Avanti CB products were produced by Antenna Specialists for a while, and then got totally discontinued.
Oh, and the Astro-Phantom was famous for one thing. Flying off the windshield at high speed, never to be seen again. They never did get the glue quite right.
73