Because the rat's nest wasn't quite bad enough yet... After being back ordered for 3 months, I finally received the antenna coax (RG400) and got started pulling it for the two com antennas, ADSB, transponder and Garmin GPS antenna. I still have to crimp connectors on each end (I'm just going to do one end and then will do the other end once all devices are in place and I cut the coax to the final length).
After going back and forth with both Dynon and an antenna manufacturer, I am comfortable with my com 2 and ADSB location behind the baggage bulkhead. It was obvious Dynon wanted to only officially say that the recommended distance between ADSB and the com antenna was 3 feet, but once I pressed them on why, they kind of backed off of that. They said that their general guidance on distances for antennas is "stacked in favor of more room is better" but that in reality the com and ADSB are unlikely to see issues being closer together. Worst case scenario is that I could notice ADSB traffic dropping out momentarily when transmitting on com 2 (which won't be common use - it'll typically just be used for monitoring). That's a non-issue and hardly a reason to bend over backwards to try to separate the antennas more.
I also heard back from Don at Delta Pop Antennas. He's known for being THE guy for experimental aviation antennas. He said there's hardly a single GA plane on the planet that could satisfy every manufacturer's recommended installation instructions for antennas. Based on his direct experience and years of asking pilots about their own experiences, he thinks my setup will be just fine.
So with that uncertainty checked off, I went ahead and dimpled all of the holes for the aft doublers. They're ready to rivet once I have a second set of hands to help get under the fuselage. You can see the coax runs for those two antennas, plus the GPS antenna that is on the top skin.
One thing I did change after doing some research was the location of the wiring that goes from the ELT to the panel for the remote trigger. I probably would have bought a different ELT had I known how this one was put together, but that ship has sailed. This ELT uses generic telephone wire to go to the remote trigger in the panel, and apparently some people have issues with the ELT going off when it shouldn't. The assumption is some sort of RF interference, probably through that cheap telephone cable. I'm going to move the routing of that cable so that instead of the direct run forward, which would have it ultimately go right by the transponder antenna and run alongside that transponder wire up to the panel, it crosses over to the other side of the baggage compartment and then goes forward. That should at least keep it away from the high power transponder and help with interference issues.
