Additional wiring to empennage

[Bill Whitefield]

I am planning on a panel upgrade that started out with just relocating the two GPS antennas from their present location over the forward baggage compartment. It has quickly grpwn into a desire to do a total panel upgrade. I would like to remote a new Dynon #2 radio, transponder, and ADSB in boxes in the empennage along with placing the Garmin and Dynon antennas directly behind the rear seat under the canopy. The builder ran an impressive bundle of wire coming forward from the empennage (rudder trim, elevator trim, pitch trim, ADAHARS, thermocouple, VOR antenna, strobe and ELT) which has pretty much filled up the pass through holes in the spar. Any suggestions on how to get the additional wiring for the remote boxes back to the empennage?
I know a lot of folks mount their GPS antennas in the engine compartment. Has this installation location worked well? I will be using a Garmin 650 and Dynon Skyview HDX. Thanks in advance for your input.
Bill

 

[Carl Froehlich]

I would first look at the rib passthrough holes right below the canopy rails on both sides. If you are lucky you may have room to run more wires through these.

I’m not a fan of GPS antennas under the cowl. I’ve always mounted the Dynon GPS antenna/receiver on the glare shield (with a dark gray cloth cover to eliminate glare). The GTN-650 antenna is mounted just behind the rear seat - the canopy slides over it and is under the canopy when the canopy is shut.

Do not mount the 650 antenna on the glare shield. Considering the known issues with the 650 GPS it is too sensitive to other stuff in that location.
Carl

 

[PhatRV]

I am planning on a panel upgrade that started out with just relocating the two GPS antennas from their present location over the forward baggage compartment. It has quickly grpwn into a desire to do a total panel upgrade. I would like to remote a new Dynon #2 radio, transponder, and ADSB in boxes in the empennage along with placing the Garmin and Dynon antennas directly behind the rear seat under the canopy. The builder ran an impressive bundle of wire coming forward from the empennage (rudder trim, elevator trim, pitch trim, ADAHARS, thermocouple, VOR antenna, strobe and ELT) which has pretty much filled up the pass through holes in the spar. Any suggestions on how to get the additional wiring for the remote boxes back to the empennage?
I know a lot of folks mount their GPS antennas in the engine compartment. Has this installation location worked well? I will be using a Garmin 650 and Dynon Skyview HDX. Thanks in advance for your input.
Bill

The big RG400 antenna wires are pretty big and if you ran all of them through the snap fittings at the spar, then you will run out of space very soon.

But if you mount your remote radio, transponder box, ADSB box at the rear of the airplane, then you don't need to run the RG400 wires through the spar. On the plus side the heavy RG400 cables from the rear will be short and and they will save some weight. Little things like this add up to a few pounds of weight saving in no time.

Also, if you are using Dynon skyview, arrange to have all of your skyview network connections at the rear hub of the airplane and only run 1 skyview network cable forward from the rear hub to the main EFIS, that will also save a lot of space as well.

I mounted my Dynon GPS antenna right behind in the same place in the picture above. I don't have problem receiving GPS signal. I mounted the backup GPS backup antenna at the engine compartment since I wanted to minimize the RG400 wiring run from the antenna to the G5 unit at the panel to save weight.

 

[RV8JD]

My previous RV-8 has a Garmin GPS antenna on the turtledeck under the canopy. Works well, as you would expect.

My current RV-8 has the Dynon SV-GPS-2020 GPS ANTENNA/RECEIVER MODULE mounted under the cowl. It has good reception and have not had an issue. Don't mount it too close to the firewall to avoid blocking issues.

Screenshot of my typical GPS fix status. The Dynon manual explains acceptable and unacceptable fix status.