Distance between Dynon and Garmin GPS Antenna/Pucks

[Lynnb]

I searched and couldn't find an answer on the distance between my two GPS Antennas, one being the Dynon SV-GPS-2020 and the other being the Garmin GA35. I know that per the manuals the Dynon needs to be 36? from any transmitting (COM) Antenna and the GA35 needs to be 24?. What I can?t figure out is what should be the minimum spacing between the Dynon and Garmin GPS pucks be.

Thanks in advanced,
Lynn

[DanH]

The install manual for the GDL-82 WAAS antenna says 9" is the minimum to any other passive (GPS or XM) antenna.

[Lynnb]

Ok, my current plan has them about 12" apart so sounds like it will work.

Thanks,
Lynn

[bill v]

I planned on side by side in the engine compartment with a mount on firewall will that work?

[Lynnb]

Originally Posted by bill v

I planned on side by side in the engine compartment with a mount on firewall will that work?

I can't speak for others, but I have a COM antenna mounted on my rear upper deck and I can get 24" away from it with the Garmin and still have it on the aluminum skin, to get 36" away from it, puts the Dynon on the fiberglass top. I had kicked around the idea of putting the dynon under the cowling, even ordered the bracket that the RV12 plans use for it, but in the end decided it would be easy to mount on the cabin top. Now if I hadn't mounted a top COM antenna, I would have just stuck them both back on the back deck.

[jwilbur]

Originally Posted by Lynnb

I can't speak for others, but I have a COM antenna mounted on my rear upper deck and I can get 24" away from it with the Garmin and still have it on the aluminum skin, to get 36" away from it, puts the Dynon on the fiberglass top. I had kicked around the idea of putting the dynon under the cowling, even ordered the bracket that the RV12 plans use for it, but in the end decided it would be easy to mount on the cabin top. Now if I hadn't mounted a top COM antenna, I would have just stuck them both back on the back deck.

The Dynon puck does not need a ground plane so it can go on the cabin top. I can't remember if the Garmin puck needs a ground plane, but it does require a minimum cable length and a special grounding mesh if installed on a non-conductive surface (e.g., the cabin top) so installing it on the tailcone makes good sense. I have my comm-1 antenna (with a ground-plane extension up onto the cabin top), behind that the garmin puck (can't remember minimum distance but adhered to it), and behind that the ELT antenna on top of the tailcone, and my Dynon-2020 puck between the doors on the cabin top. I've had no performance issues on any equipment.

[Lynnb]

Originally Posted by jwilbur

The Dynon puck does not need a ground plane so it can go on the cabin top. I can't remember if the Garmin puck needs a ground plane, but it does require a minimum cable length and a special grounding mesh if installed on a non-conductive surface (e.g., the cabin top) so installing it on the tailcone makes good sense. I have my comm-1 antenna (with a ground-plane extension up onto the cabin top), behind that the garmin puck (can't remember minimum distance but adhered to it), and behind that the ELT antenna on top of the tailcone, and my Dynon-2020 puck between the doors on the cabin top. I've had no performance issues on any equipment.

Thanks Joe.

[219PB]

Originally Posted by bill v

I planned on side by side in the engine compartment with a mount on firewall will that work?

I installed my Dynon and Garmin under the cowl and have over 12" between them. I believe that it was in the Garmin manual that stated it needed at least 12" between GPS pucks.

I should be able to get the oil filter off with the GPS as they are. If I need a little more room, the GPS rack comes off with the removal of the 4 screws.





http://www.kitlog.com/photos/project...2017A00018.jpg

[jwilbur]

Originally Posted by 219PB

I installed my Dynon and Garmin under the cowl and have over 12" between them. I believe that it was in the Garmin manual that stated it needed at least 12" between GPS pucks.

I should be able to get the oil filter off with the GPS as they are. If I need a little more room, the GPS rack comes off with the removal of the 4 screws.

Personally, I wouldn't put them here. The distance between them may be fine but the airplane itself will shadow any signal coming from the rear. In other words, a satellite signal from the back will be invisible. For travel on the ground all we need are a few satellites in view to get a good 2D location fix. In the air we want as many satellites in view as possible in order to get a 3D location. And the further apart those satellites are from each other the better the 3D fix. That means satellites overhead along with satellites at low angles (closer to the horizon) together give us the best position in 3 dimensional space. In this location any satellites behind the aircraft are useless. ... This is essentially why in an aircraft we use external GPS antennas at all. In your car we don't care. Any position fix is typically good enough. Not so in an airplane.

I would recommend moving them - particularly if you intend to do GPS LPV approaches.

[Tankerpilot75]

I have three Garmin gps antennas under my engine cowling. Two non-WAAS antennas (for my 430 non-WAAS unit?s) and one WAAS antenna for my 335 ads-b unit. The distance between all three units is about 16 inches. The non-WAAS antennas have been positioned there for about eight years and the WAAS antenna for two years. Have not had any trouble at all with the antennas (knot on wood). Just remember while separation distance is somewhat flexible the minimum length of your WAAS antenna wire is not. Unfortunately, I do not remember that minimum length you need to have but you can call Steinair to confirm it. Just loop the wire under your panel.

Good luck.