RV-12 ADS-B antennae location

[JRo]

So today I received my ADS-B for my RV-12. The box looks easy enough to install, just above the comm radio. The antennae, however, is to be installed on the belly, behind the aft cabin bulkhead, in the vicinity of the left static port. To route the cable, the removal of wings, canopy, seats, carpets, many floor panels, aft cabin bulkhead, etc. are all required. In all, a difficult antennae installation.

I was thinking, why not mount it farther forward on the belly? I called Dynon, and they knew of no reason other than that it must be 2' from engine/propeller, mounted vertically on the belly, clear of gear doors (N/A) and access panels.

Any of you mount the ADS-B antennae farther forward on the belly, or know of a specific reason why I can't?

Jim R.
N448JR
1.7 hours of flight testing complete

[txaviator]

I don't have a technical answer. However, I'm non-flying, and no wings installed. And it was a BEAR to run that cable back there all that way. The flaperon pushrods are really in the way, etc. A bunch of work for sure. I wish I'd have installed it WAY earlier in the build.

[DonFromTX]

For the non ELSA types, I mounted the box on the rear side of the baggage bulkhead, and the antenna close by. If you were converting from the 180 wiring to the Skyview, there were already some unused wires, so you did not have to string anything thru the tunnel!
That said, I installed a nav/com and now have to run an antenna wire to the rear after all!

[JRo]

from the thread starter:

Well, I called Dynon, and they said the ADS-B antennae has to be mounted vertically on the belly, more than 2 feet from the engine/propeller, clear of gear doors and access panels. They asked why I wanted to mount it so far aft, and I said Vans instructions. They said call Vans.

So I called Vans. They said it was a Dynon thing. I asked if there was any clear reason why the antennae has to be so far aft. They didn't know of one. I'm not particularly a lazy type, but I don't relish the idea of tearing apart a plane that took over a year and a half to build, just to install an antennae in a hard-to-reach spot when no one knows why.

So, I plan to locate it on the belly, but somewhere forward of the main wing spar(s).

Anyone see a problem with that?

Thanks,

Jim R.

[rvbuilder2002]

Originally Posted by JRo

So, I plan to locate it on the belly, but somewhere forward of the main wing spar(s).

Anyone see a problem with that?

I believe the ant. location is to meet a distance requirement from the transponder ant. (which on the RV-12 is located fwd).

Keep in mind... The ADS-B system is receiving transponder signals

If you take a look at the new RV-14, the ADS-B ant. is located at teh far aft end of the tail cone, because the transponder ant. is under the baggage area. Same reason... separation from the transponder ant.

[Mich48041]

Dynon recommends a minimum of 2 feet of separation between the ADS-B and transponder antennas according to their posting:
http://dynonavionics.com/cgi-bin/yab...m=1357586067/2
I read someplace that Garmin recommends 3 feet separation.
Joe Gores