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The silver coating that is used for UV protection on the covering would at first glance seem conductive to me. If this is the case, installing the ELT antenna internally would not work. Does anyone know if the silver coating is conductive?
Thanks
tom
Tom, the silver coating is powdered aluminum mixed in with the other stuff as a paint. There's a lot of "other stuff" in & around all those little aluminum particles. I don't think you could measure any conductance across the surface. But regardless of that, the ELT antennas mounted inside the airframes of Kitfox aircraft have proven to work just fine.
I checked with Poly Fiber and got a response from Conair.com
"
Treat it as a sheet of aluminum. It impedes radio transmission, though I have never stood on one side of an aircraft touching a hot-wire to the skin and had someone else on the other side touching it to see if they would get shocked. Hope this helps."
I will be mounting my ELT externally.
Thanks
Tom
My friend, Stan, has his ELT antenna mounted inside the airframe (polyfiber covered), just like MANY other Kitfox aircraft, and had it accidentally activated just a couple of years ago while parked on the ramp. The emergency response (from the Air Force?) was approximately 10 minutes as I recall. He got a phone call, before they sent out the Mounties. It may not be the ideal location as far as transmission is concerned, but it seems to work, and there are other important considerations. I've heard and read that one of the most common failures of ELTs is the antenna getting ripped off the airplane or separated from its connection during a crash. MUCH less chance of that happening if it's within the airframe. It's also nice to eliminate as many protuberances as you can. Just some food for thought, since you asked.
My comm antenna is mounted in the tail under the fabric and I've never had difficulty talking air to air or air to ground. I also mounted my ELT antenna in the fuselage like many others. As John said, much better chance of surviving a crash there compared to the exterior of the aircraft. The only antenna on the exterior of my model 4 is the transponder blade.
I also mounted my ELT antenna inside the Kitfox airframe for the reasons stated below. Call the ELT supplier if you are still doubtful.
One of the first questions from the first responders when my wife and I were laying on the ground beside my destroyed Model IV - "Where is your ELT?" Antenna inside mounted upside-down beside the baggage sack.
After a mishap, why would that be one of the first questions asked by an rescue personal? Or why ask that question at all?
I think because they need to turn it off as soon as possible.Quote:
Originally Posted by Flybyjim
So Highwing, did the ELT bring the responders? In other words did it do its job from inside the fuse?
No, it was just making noise from inside the fuselage . It would have brought the responders if we hadn't put it down so close to a Calfire station.Quote:
Originally Posted by jiott
Just an update on the question of whether to mount the ELT internally. I just finished putting the Poly-spray on with a nice clean finish. I took an ohm-meter and probed in with the two leads about 6" apart. I still had "infinite" impedance. This implies the coating is non-conductive and will cause no loss to the transmission of the ELT signal.
My earlier post where I said that the poly-spray rep said that it is like a sheet of aluminum - I question his statement.
Tom