Grounding plane
- Thread starter montyj
- Start date
Are you rebuilding the aircraft and have the fabric off? As I recall, the original is an aluminum plate mounted between upper wooden stringers and bolted to the steel frame. Then 6 copper wires are run down from the plate, down to the lower stringers through small holes drilled in the stringers. These form the extended ground plane
These seem to work well and last at least as long as the fabric.
These seem to work well and last at least as long as the fabric.
FYI-
The FAA recommended installation uses copper ribbon. Due to poor transmission with the factory install using brass wires I replaced my ground plane with one using copper ribbon and had a significant improvement in transmitter performance. In the factory installation the brass wires were swaged together in the center, the loose swag caused static and a dead spot aft of the aircraft which was discovered while making a 360 while receiving ATIS. Proper ground is very important.
Tom-
The FAA recommended installation uses copper ribbon. Due to poor transmission with the factory install using brass wires I replaced my ground plane with one using copper ribbon and had a significant improvement in transmitter performance. In the factory installation the brass wires were swaged together in the center, the loose swag caused static and a dead spot aft of the aircraft which was discovered while making a 360 while receiving ATIS. Proper ground is very important.
Tom-
Tom, could you expand on how your antenna is now installed? I have the very same trouble, i.e., blind spot at the tail. I cannot receive clear transmission from as little as a mile away when the tail points to the tx antenna. I have an SL40 and 1/4 wave mounted on the top rear fuselage and 6 (copper?) wires for the ground plane. I have not removed the antenna to see how well these wires are attached but the aircraft is covered and it appears that access to all the wires will be difficult. How many, how long, and wide are your copper ribbons and how have you attached them?
Thanks so much for your help,
Pete
Thanks so much for your help,
Pete
Tom, Please respond to the above reply. I am having the same problem and the avionics shop wants to sell me a new antenna. Last time I looked at the installation I don't remember seeing any wires acting as a ground plane. My first aircraft, a 7EAC had a simple bent wire attached to the wing root fairings. I do not remember how well the com worked. It was my first aircraft and I believe if I had any problems I would have attributed them to a lack of pilot experience and proficiency. Since that time I have flown a Maule with instrument rating and had excellent communications. Now, I am back with 8KCAB and have com problems, poor trans and recieve, especially through tail. This time I know it is hardware and not software (pilot). Any help / suggestions would be appreciated, what about wing fairing?
Thanks,
Ken
Thanks,
Ken
Pete, Ken-
Sorry for the delayed response, just noticed your postings.
I have the SL-40 also, excellent, highly recommended.
My radio guy had 2-3' wide copper tape which we cut into 1' strips that we then covered with shrink wrap so there wouldn't be anything sharp in the aft fuselage. We used 6 or 8 strips that were each 6-8' in length and attached them in the aft fuselage to the wood formers using the holes that the factory used for the brass wires. The new ground plane is attached to the bottom of the aluminum plate (very small ground plane) that the factory mounts the antenna on by removing the antenna and drilling a countersunk hole.
The two problems with the original were that the wires were loosely connected at the swage and that for reflective purposes a flat ribbon is vastly superior to wire. I've seen WWII era military fabric aircraft that used a fine wire mesh for the ground plane. If I was installing one at time of cover I would consder that or use of a very thin (light) foil.
The installation is not much fun, remove the rear seat and battery box to improve access, find a radio man who likes to solve problems not merely replace parts to provide advice and technical assistance. But in the end this isn't rocket science you need a reflective surface that is electrically bonded to the antenna base.
Tom-
Sorry for the delayed response, just noticed your postings.
I have the SL-40 also, excellent, highly recommended.
My radio guy had 2-3' wide copper tape which we cut into 1' strips that we then covered with shrink wrap so there wouldn't be anything sharp in the aft fuselage. We used 6 or 8 strips that were each 6-8' in length and attached them in the aft fuselage to the wood formers using the holes that the factory used for the brass wires. The new ground plane is attached to the bottom of the aluminum plate (very small ground plane) that the factory mounts the antenna on by removing the antenna and drilling a countersunk hole.
The two problems with the original were that the wires were loosely connected at the swage and that for reflective purposes a flat ribbon is vastly superior to wire. I've seen WWII era military fabric aircraft that used a fine wire mesh for the ground plane. If I was installing one at time of cover I would consder that or use of a very thin (light) foil.
The installation is not much fun, remove the rear seat and battery box to improve access, find a radio man who likes to solve problems not merely replace parts to provide advice and technical assistance. But in the end this isn't rocket science you need a reflective surface that is electrically bonded to the antenna base.
Tom-