Antennae (1.5h)

So it has been a while but I finally dragged my lazy self back to the hangar to get over the phase that has been bothering me for so long: antennae.

Where and how to install an antenna is not mentioned in the manuals or the plans or the videos, presumably because you could decide not to install any. Oh, and because at this point in the build it is assumed I have acquired 20 years of aircraft building and don’t need the help any more (topic for future rant).

Anyway, I need/want two antennae on the top of the frame – the ELT (for the FAA required emergency locator transmitter) and a COM (for the radio). Because of minimum distances needed between the antennae I chose to set the ELT quite far back down the frame, at a position I won’t be able to easily get to once the baggage back has been riveted. So I decided to take everything apart and set the rear fuselage on the ground so I could get inside it.

As a small diversion, now was also a good time to start on the A6 rivets that I had mistakenly drilled in the top of the rear fuselage. Since these have to be done by hand, now is a good time so that I can get above it and give it some proper wellie (as they say in the aviation industry).

I can do about 6 or 7 in a go before my arm wants to fall off.

The COM antenna comes with a handy mounting template so I put it on the top and drilled the appropriate holes. Trying to think about the best place I thought that using one of the stiffeners would be a good idea and in retrospect I think it was but I should have put one of the mounting screws in it, not the antenna base. Its done, can’t go back.

For the speeds that this plane files at, I think that I probably don’t even need backing plates for these antennae but I emailed Don at deltapopaviation about it and he said it was a good idea anyway so I just found some sturdy pieces of scrap metal and made some plates. One for the ELT

and one for the COM

I saw some examples online that were works of art, mine are not. Seriously, if the plane ever makes it off the ground I’ll be very happy if the antennae don’t go flying off opening the roof like a soup can.

Oh, somewhere amongst the process I finished all my hand riveting:

After match drilling the holes in the backing plates to the top skin I had to get inside to cleco the ELT plate so that I could rivet it. Our dogs had to sacrifice their precious lounge seat for my comfort

And then, for the first time ever, I got to go inside my plane!! Though I always figured I’d be up front though it sure is comfy in the back!

Using the caulk suggested in the EAA video on how to install an antenna, I smeared some around the edge and put the ELT antenna in place, crawled inside and tightened the washer and nut.

Same thing for the COM antenna:

and so from a distance at least, it appears I am done with these two for now.

Still to do before I can rivet the baggage back (and then the rest of the rear fuselage and join the two halves together) is to make up an RG-400 cable and plug it in to the ELT antenna. I’ve been struggling to crimp a connector onto my cable which has been half the reason I couldn’t get back to the hangar but twenty+ years ago it was my job to install a whole network of coaxial and I never had any problem. So I don’t know what is going on. Hopefully I’ll do that next week and we can get the fuselage back on the stands and riveted into one piece…. and then on to the wheels!