I have two multiband trap verticals They are not exactly the same, but
close. Obviously they're intended to be mounted vertically above a ground.

What happens if I mount them horizontally, base-to base? If I feed one with
coax as designed, would it see the other one as a counterpoise? Could I
remove any base matching components and feed them both with a 1:1 balun, in
effect duplicating the function of a horizontal wire trap dipole?

I'm really impressed with the lower noise of a horizontal antenna. Screw
the directionality drawbacks of a horizontal! I can hear more stations.

I am having great fun with HF. My 10 meter copper pipe dipole is laying on
the roof with one element extended using a short clip lead and some RG-6 TV
coax. Tonight, my Kenwood TS-120 reached out from San Diego for a QSO with
New Zealand on 20 meters, my first contact outside this hemisphere. Neat.

"Sal"
(really KD6VKW)