External Antenna Considerations

[M Towsley]

Hey guys,

I know this has been discussed here before but I am not finding exactly what I need.

I recently moved my plane to my hometown airport, which also happens to be class C airspace. The transponder is not an issue as I obtained a year-long waiver.

The problem is the radio issue. I use a handheld ICOM A-6 with a temporary base-loaded outside mounted antenna. I was able to talk to the tower relatively easily but a recent issue of them not hearing me has got me thinking I need a more permanent and better solution.

Right now the only option I see is the bottom mount between the gear legs. My former BC-12D had a top-mounted antenna behind the cockpit but that area cannot be accessed. I had great range with that set-up.

I was considering the R.A. Miller AV-534L, but that antenna seems to have an awful lot of height from base to the tip of the bent antenna. I am worried about having enough room from the bottom of the plane to the ground. Is anyone using this set-up?

Does anyone else have an installation that is easily obtained and installed? An A&P/IA friend of mine will be assisting with the install. Pictures would be helpful.

As always, thanks in advance!

[mikerice]

Re: External Antenna Considerations

We installed a R.A. Miller AV-534 and made our own leads, since I had the coax and the tools. Using the "L" with the 8 foot coax would speed the install.

We put it under the floor panel on the copilot side. WE drilled a hole in the boot cowl through an existing doubler and it has worked great. We were worried that it hung too low, and that the gear would shield the antenna on the ground, but reception has been great. We tested the antenna and a Sportys handheld SP400 to 10 miles and the tower heard us fine.

I am working on a portable radio install with a 14 AH sealed battery and a MGL Avionics V10 radio that I got from Aircraft Spruce. The box fits well in front of the seat, and the radio has a built in intercom. Still testing the setup, as you have to do a lot of wiring to connect the headphone and microphone jacks, and the built-in intercom has a lot of adjustments. Everything is self contained and only needs the antenna connection. I flew with it today and the tower said it sounded great, but the side tone was scratchy and very loud. Still working out the kinks..

[M Towsley]

Re: External Antenna Considerations

Thanks Mike for the info. I am looking probably to go this route, but I definitely need better than 10 miles for sure. The outer ring is 10 miles and I need to speak to them before that.

I am sure this antenna setup will work far beyond that, as I used to talk to people well over 100 with my old Sportys radio and fixed antenna on my first BC-12D.

Still looking for more advice and experience with this, or any other, set-up. Thanks again, Mike.

[mikerice]

Re: External Antenna Considerations

The range on the Sportys SP 400 and RAMI AV534 antenna was way more than 10 miles, as we were clearly hearing people in the pattern at an airport 42 miles away. We are not sure on the transmit range, but I would not be surprised at 15-25 miles, we have just not tested it that far.

[3Dreaming]

Re: External Antenna Considerations

Marty, we used one of these in the clip wing that's down here and it works really well. http://www.aircraftspruce.com/menus/...composite.html
It is attached to a wooden piece and mounted on an angle behind the seat. Tom

[M Jones]

Re: External Antenna Considerations

Marty, we used one of these in the clip wing that's down here and it works really well. http://www.aircraftspruce.com/menus/...composite.html
It is attached to a wooden piece and mounted on an angle behind the seat. Tom

I've been using that same antenna and mounting method also for many years. The tower at KDEC has complained at times, but it works pretty well for the most part. It seems to be a little weak when transmitting nearly straight forward. If I just make a slight turn they seem to hear me. Receive range seems to be good for sure.

[M Towsley]

Re: External Antenna Considerations

Has anyone ever used the RAMI AV-17 antenna? Link: http://www.rami.com/product-view.php?pid=20

I know it is a little overkill, and expensive, but the AV-534 is awfully long sticking out of anywhere on the plane and the 17 is a lot less height.

I now remember the L-2B I had utilized the 534 on the boot cowl. It was very long mounted there.

Thanks for the help.

[woodmw]

Re: External Antenna Considerations

Anyone try an Advanced Aircraft Electronics VHF-5T as referenced in this post @ j3-cub?

http://www.j3-cub.com/smf/index.php?topic=4590.0

[3Dreaming]

Re: External Antenna Considerations

Anyone try an Advanced Aircraft Electronics VHF-5T as referenced in this post @ j3-cub?

http://www.j3-cub.com/smf/index.php?topic=4590.0

That is the same one from ACS that I mentioned earlier in the post. It does a good job. Tom

[magman]

Re: External Antenna Considerations

In order to have good antenna performance it is necessary to provide the antenna with a good "Ground Plane".

It can be fabbed from thin alum or even foil.

AC 43.13-2b has info on this.

A bud has a very late PA-18 & it has thin alum inside the fabric

and RIVETED to it.

[Pearson]

Re: External Antenna Considerations

I too have the AV534 bent antennae mounted on the bottom of the boot cowl. I use a Yaesu handheld and have talked to a control tower over 100 miles away while flying at 2000'. I never dreamed a handheld would do that, but I found out by accident one day by being on the wrong frequency.

[M Towsley]

Re: External Antenna Considerations

I ultimately went with the AV-534 and will post some pictures so if anyone else has a question on how to do it hopefully the pictures and description will help.

[wingwalkers]

Re: External Antenna Considerations

Marty, I am restoring a (46) BC 12 D and I am going to put a Skywave Atenna inside the fus behind the baggage area. The gentleman that makes this atenna is a very knowlegeable man on this subject and very interesting to talk to. His name is Paul Johns and he is 98 and flew the flying boats back in the day. Look his website up by typing in Skywave Atennas for aircraft. Let me know what you found out. I had already purchased his antenna bfore I went to Oshkosh this past July. So when we went to wisconsin, we looked him up and had an enjoyable afternoon listening to him.

Keith Walker