GHA-15 Mounting Location

[Phil Sprang]

The GHA-15 is fairly new and has some interesting limitations on installation.

I’m interested to see where folks have mounted their antenna.

Of particular interest to me is on an RV-14

This thread might be a good place for people to share info regarding their installation. Aircraft model, distance from easily recognized “landmarks”, pictures, etc. Whatever you can think of to help the next person.

Thanks in advance.

Still building but received my GHA-15 today.

 

[bjdecker]

Repurpose the UAT antenna mount hole at back of the tailcone.

 

[Traash]

RV-10. Under front seat as close to tunnel wall as possible. Easy to get to, inline with main gear (at center of rotation so pitch attitude won't affect height, easy to splice into CAN bus wire that goes out into wing.

 

[MS19087]

Any updates here? RV-14A

Interested in where folks have mounted this unit on a -14A.

Thanks!

 

[Phil Sprang]

I finally got mine mounted on a -14. to my surprise, it was a lot tougher than I envisioned when I ordered the GHA-15. My fuselage has the floor installed which made it difficult due to lack of access. Difficult but not impossible.

I temporarily installed the comm antennas and one step so that I could “map” the belly for the 120 degree cone of no obstuctions.

Here are some pictures of the belly with black electrical tape marking the areas, from the belly edge, where the GHA-15 can’t go, due to the comm antennas and the steps.

I’m not sure how to imbed the pics in the post but I’ll try to explain.

The middle picture is of three possible locations under the left seat. They are desirable due to being closer to the wheels. In each case, part of a com antenna sticks into the 120 degree cone. the amount of antenna is marked with a piece of tape. I chose not to use these locations.

The picture with a cardboard mockup of the transponder antenna is for a buddy. The yellow tape denotes the edges of the 120 degree cone. He is mounting his GHA-15 in the same place as mine and the transponder antenna will not interfere.

I also mapped the flaps, full down, on a friends plane but didn’t get a picture. It is a similar arc to the step but slightly forward and slightly smaller.

I elected to mount my GHA-15 opposite the location on the belly where Vans calls for the transponder antenna, under the baggage floor. I’m using the transponder antenna location for a belly beacon. The GHA-15 is on the opposite side of the center tunnel.

Due to the baggage floor being installed, I had to fabricate the antenna doubler in 4 pieces in order to fit it through a rib hole, then assemble it under the floor.

The location where my GHA-15 is located will vary in height by 10” from a three point stance to wheel landing stance. While I wish I didn’t have that variation, that is part of having conventional gear and very few possible mounting location options.

The center tunnel was determined to be a no-go location due to the proximity of the control pushrod. The GHA-15 connector sticks up approximately 2.5 inches.

One of the mounting requirements is a minimum of 20” from the ground. That can be maintained as far aft as the static ports.

 

[rdamazio]

For me it was in the tunnel, roughly underneath the fuel valve. Added a bit of sealant to prevent any leaked fuel from reaching it.

I had a doubler laser cut (is that a bad word now? it was not the same vendor that Vans used), mentioned and shared the file here.

 

[echozulu]

I put mine behind the baggage bulkhead.
Had two locations, either beneath the front seats or behind the baggage bulkhead. However, I had a bent whip antenna beneath the tunnel and the tip of the antenna intruded on the GHA cone. Talked to Garmin about it and they would rather see it further away from the CG than an intrusion into the cone.

 

[rongawer]

RV-10 location

For me it was in the tunnel, roughly underneath the fuel valve. Added a bit of sealant to prevent any leaked fuel from reaching it.

I had a doubler laser cut (is that a bad word now? it was not the same vendor that Vans used), mentioned and shared the file here.

I put mine in the same spot.

I think this is a perfect use case for laser cutting, so well done. For my doubler, I resorted to my ruler, sharpe marker, mini mill and a deburring wheel on some scrap 0.050” sheet.

This location provides a near center of pitch and roll, yet still provides the 8” or so of radiation to body clearance from footwells and seat bottoms, along with meeting ground clearance.