MainlandCub said:
Where on earth can you mount a vertically polarised externally mounted antenna aft of the cabin with sufficient ground plane on a Super Cub?
...[snippage]...
I remain unconvinced to move it from inside the fuselage.
Quote from earlier mess: ""I had read (I think here, some time back) that some have the ELT antenna mounted inside the (fabric) fuselage. I thought this was a good idea, to help keep it protected from brush/branches/whatever, AND keep it out'a the way for sweeping snow off. I checked w/my local 'lectronics guru & he thought it would be fine too. He understands RF stuff & said the tubes would not appreciably reflect power nor hurt transmission.
THEN he said, wait... it's not just fabric, it has a few coats of aluminum on it. He has a super-testing gizmo (I think he said it was $14K!) Anyway, we tested transmission from outside, and inside, and the aluminum cut it back by 10db! He said that's effectively letting 1/8th of the RF out.""
Note: I do my own maintenance (with adult supervision).
Mount... what I did was to screw a piece of aluminum to the aft U-channel (on my 18-A) above the ext.baggage area, and then glued it to the underside of the fabric behind that. After much pulling/tugging (my cert. process) I was satisfied that it was as strong (G-force wise) as the ELT mount itself, so drilled the hole & mounted the vert. antenna in the middle of the aluminum.
Tested again with his expensive gizmo & 100% output.
This guy is a retired electronics professor & also his hobby. He built our FM radio repeater system(s) and also the TV/radio rebroadcasters on the fire lookout mtn. Point is: he knows what he's doing.
If you got CAP attention through your "aluminized" fabric & metal hangar, you were lucky. As in anything, YMMV. Me... I want ALL of my RF reaching out there!