---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 04/12/22: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 08:45 AM - Re: Transponder antenna ground plane (Robert L. Nuckolls, III) 2. 11:16 AM - Re: Transponder antenna ground plane (Eric Page) 3. 03:34 PM - Re: Transponder antenna ground plane (user9253) 4. 04:59 PM - Re: Transponder antenna ground plane (Eric Page) 5. 07:42 PM - Re: Transponder antenna ground plane (user9253) ________________________________ Message 1 _____________________________________ Time: 08:45:31 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Transponder antenna ground plane At 01:57 PM 4/11/2022, you wrote: >Forgot to ask ' should the ground plane be >=93grounded=94 to the fuselage as some suggest, >should it be isolated from the fuselage, or does it make any difference? > >The ground plane probably should be grounded to the fuselage for lightning >protection. But I don't think it matters for performance. > >-------- >Joe Gores Agreed . . . and yeah, making the ground plane from a hexagon or octagon cut our on a shear makes good sense labor wise as opposed to cutting out a circle. I was fixated on demonstrable performance as opposed to practical convenience! Bob . . . Un impeachable logic: George Carlin asked, "If black boxes survive crashes, why don't they make the whole airplane out of that stuff?" ________________________________ Message 2 _____________________________________ Time: 11:16:35 AM PST US Subject: AeroElectric-List: Re: Transponder antenna ground plane From: "Eric Page" I put transponder and ADS-B antennas inside the wings of my Kitfox. The ground planes were made from a piece of very thin galvanized steel flashing material that I sourced from Home Depot. I drew circles on the material in the required sizes, rough-cut the parts with hand shears, then shaped them to final size in a couple of minutes with a disc sander. The center hole was made with a step drill, then the parts were coated with zinc chromate primer. I removed primer from a small area around the center holes to ensure good electrical contact to the antenna. I think my total investment in the parts was about $4 and one hour of labor. A couple of varnished wood sticks and some structural epoxy mounted them securely inside the wings, well away from the spar tubes. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=506541#506541 Attachments: http://forums.matronics.com//files/img_1376_163.jpg ________________________________ Message 3 _____________________________________ Time: 03:34:47 PM PST US Subject: AeroElectric-List: Re: Transponder antenna ground plane From: "user9253" Nice work Eric. Is the antenna on the bottom or top of the ground plane? Does it matter? -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=506542#506542 ________________________________ Message 4 _____________________________________ Time: 04:59:52 PM PST US Subject: AeroElectric-List: Re: Transponder antenna ground plane From: "Eric Page" user9253 wrote: > Is the antenna on the bottom or top of the ground plane? > Does it matter? In flight, the radiating elements (pointing up in the photo) will point down toward the ground, and the BNC connector will face up. Not sure about your second question, but I've only ever seen transponder antennas on the bottom of airplanes, pointing down. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=506543#506543 ________________________________ Message 5 _____________________________________ Time: 07:42:28 PM PST US Subject: AeroElectric-List: Re: Transponder antenna ground plane From: "user9253" Next year Canada is going to require aircraft flying in Class A & B airspace to be able to send transponder signals to satellites. This requirement can be met either through antenna diversity (the use of a top and bottom antenna) or with a single antenna that is capable of transmitting both towards the ground and up towards satellites. I have never seen transponder antennas on top of airplanes either. But chances are that an antenna on top would work just as well as one on the bottom. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=506544#506544 ------------------------------------------------------------------------------------- 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.