Hoping you all are starting to have a great spring,
I'm getting ready to mount a Garmin WAAS GPS Antenna and wonder where did you install yours and does it work well there. I have the drawing from Maule which puts it on top of the wing like at station 57" or so.
Thoughts?
Alan

Top of the wing. It gives you a clear view of the sky and a good ground plane.

Howdy,

I recently place my G35 where the old antenna on the Right Wing was, just outboard of the wing root. Great directional location, low profile and effective. Also easy routing of coax.

Tom

About 12" from the wing root on the top of the wing is best to avoid having to fish a coaxial cable through too many wing ribs. It's also good to have as short a run of RG-400 cable as possible to minimize signal loss. There needs to be a little slack in the cable but you don't need a 20 foot run, which is often what comes with these units. Shortening the cable requires someone who does a good job installing RF connectors with the right tools so it doesn't cause all kinds of signal loss problems. GPS units operate at 1227.6 and 1575.42 MHZ. At that frequency even a minor connector installation defect can seriously degrade the GPS received signal level.

This question has come up for me recently and I found this old thread. However, the suggestions of just outboard from the wingroot, while the first place I wanted to put the antenna, I'm not sure will work. That runs into the fuel tank. And 12" from the wing root is right in the middle of the fuel tank.

Other answers I've thought about are further out on the wing (the other side of the fuel tank), on the wingroot fairing strip (don't think it's quite wide enough), or some place above the headliner and below the fabric (not sure that silver (aluminum) in the fabric won't attenuate the GPS signal too much). Basically, I'm not happy with any of the alternatives I've been able to think of.

I was able to mount my on the wing root cover. Easy install and wiring.

Mine is just outboard of the root fairing. The avionics shop replaced an older GPS antenna so apparently they thought the spot worked well too.

I saw a harmon rocket that had the gps antenna mounted in the engine compartment. He had an aluminum mounting plate adel clamped between the last two push rod tubes. Claimed with the fiberglass cowling it was no problem. Made me go hmmm....Wonder if i could mount a vor/ils antenna in there?

Tim

There is room between the wing root and the tank. Lots of antennas mounted there. The tanks are pillow shaped (though I’ve heard not all are) so even though the middle of it (in the y axis) sits close the wing root, the curved top leaves plenty of room for an antenna.

GPS antenna on my M5-235 is located a few inches off the wing root and about 8" in front of the flap. There is an inspection ring on the underside of my Maul wing which made for easy installation. No problem with reception.

Just curious, looks like a big "bump" to be that close to the leading edge. I'm sure it has little effect on the airflow but it does not seem like a very good placement aerodynamic wise.

Ralph
Akafrank

Akafrank wrote: ↑

Wed Dec 16, 2020 3:22 am

Just curious, looks like a big "bump" to be that close to the leading edge. I'm sure it has little effect on the airflow but it does not seem like a very good placement aerodynamic wise.

Ralph
Akafrank

Probably doesn’t disturb the airflow any more than a com antenna; it’s quite common to mount those in that location.

Thanks everyone. My tank is definitely a bit pillow-shaped so I'll have a look at fitting the antenna in with that curve. Now I just need a better way to get access to this area since in the process of checking this out, I've discovered I have a fuel leak up in there. I think it's coming from around the fuel sender. One little project leads to another.

My avionics shop mounted my two GPS antennas for the Garmin GTN 650 and Stratus ESG on top of the wings just beyond the aft outboard corner of the tanks. They said that was th easiest place to get to given the location of the inspection ports. I bought the ESG before the GTN 650 so I needed an internal WAAS GPS position source. That's why it has a GPS antenna.