Ground Planes

[Marvk7]

I am not understanding the making ground planes for my comm. and transponder antennas. Can someone point me in the direction of a picture of how you made yours? One issue I am seeing is the u channel attached to the fuselage frame for mounting the antenna makes the antenna base recessed.

[Dorsal]

I mounted my antenna directly to the plate on the fuselage (no additional ground plane), works well for me. The plate is the one painted with poly brush in the pic.
http://www.teamkitfox.com/Forums/pic...pictureid=2431

[Marvk7]

Dorsal, my fuselage on has small brackets about 1 1/2 inches wide along the bottom behind the seat. I don't know if it would be enough area.

[airlina]

Hi Marv, On my Series 5 , I use a Microair comm and transponder. These radios are small low power units , that I initially tried to use without a ground plane with no success. After installation of a simple ground plane for each unit , I have had acceptable ops for the last 12 years. The photo shows the ground plane for my transponder . You can see its located just in front of my header tank and is simply an aluminum circle with aluminum spokes( pop riveted to circle )eminating radially from it. If you look close you can see ground wires from the mounting plate to the aluminum plane. the comm plane is the same located on the upper fuselage mount plate just aft of the baggage compartment. Hope this helps, Bruce N199CL

[jiott]

On my SS7 I mounted my xponder antenna to one of the welded-in u-channel plates on the bottom behind the seat; and the comm antenna to the other one. No extra ground planes at all-works fine. I have the Garmin SL40 radio and the Dynon mode S transponder.

[Dorsal]

Marv,
Like Jim I also use the small brackets behind the seat for transponder with no problems.

[KFfan]

Using 125Mhz as the transmit frequency, the "ideal" ground plane diameter should be about 23.5". We all know this is usually an impossible size for our aircraft. Additionally, the antennas for the coms and transponder should also, ideally, be separated by the same distance. fwiw

[Marvk7]

Thanks for the responses