---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 10/27/22: 1 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 02:03 PM - interesting antenna discovery (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 02:03:53 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: interesting antenna discovery Found a broken WiFi antenna in a box of 'stuff' a few days ago. Peeled of the outer jacket and found this inside. It's a classic 'coaxial' dipole . . . 1/4 wave radiator and 1/4 wave coaxial sleeve. The dimensions were a puzzling at first, they are too short for free space resonance in the 2450 MHz WiFi band. Then I recalled installing j-pole antennas fabricated from 450 Ohm 'ladder-line' for a customer some years ago. I erected radomes fabricated from PVC pipe and found that when the antenna was a tight fit in the pipe, proximity of the dielectric depressed the resonant frequency of the antenna. The use of 3" PVC and with cardboard spacers to center the antennas brought them back to design resonance. I suspect that's what happens here. The antenna is physically modified to accommodate proximity effects of the jacket. Kinda cool . . . Bob . . . Un impeachable logic: George Carlin asked, "If black boxes survive crashes, why don't they make the whole airplane out of that stuff?" ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.