Antenna Location

I'm hoping some 4 owners can give me their advice on my com, transponder and elt antenna locations and mountings. I've got a bent whip Comant that I plan on putting on the belly, preferably forward of the spar. It attaches with four screws so I thought I'd just make up a small doubler fitted with nutplates and screw it together. I'm thinking that I shouldn't need to rivet the doubler to the skin, since the screws will hold things tight. I'm aware that there needs to be good electrical contact between the doubler and interior skin so I'll strip the primer there. I'm planning the same deal for the transponder antenna, but with a small single-holed doubler. Where is the best location for these two guys? I'd like them forward of the spar, but want to stay well clear of the exhaust. Should they go along the plane's centerline? How far from each other do they need to be? On the ELT I've heard of all sorts of locations and have no idea which is the way to go. How bout some sage advice from those who've gone before me?

Steve Zicree
RV4

Antennae

Gidday, my -4 has the com whip just aft of the baggage area (on top) and the transponder ant. fwd of the spar on the LHS bottom (my exhaust exits under my right foot). From memory, with both antennas fwd of the spar as you would like interference may be a problem and is not recommended when you read the literature. Mounting the VHF whip further aft is an option provided ground clearance is OK. I've had no problems with the longer coax required to go aft, just keep all your earths good.

ciao

Antenna location

Hi Steve
My Transponder antenna is center line fuselage between the gear legs. The com antenna is aft of the spar right side belly and the ELT antenna is mounted on F410A under the empennage fairing

Hi Steve,

One of the slick spots that I've copied on my -6 for the Txpdr stud antenna was on the wing root fairing. Easy access, easy to mount, and no worrying about belly skin drilling, etc..

As far as the ELT, others have suggested good places for that and I agree with them.

Cheers,
Stein