Push-To-Talk Wiring

[PapuaPilot]

For the Garmin GTR-20/200 COM radio it says 22 gage wire is standard for everything except the power and ground wires. For my plane I used a common ground on the firewall for everything except my PTT switches. They don't carry any current and are just needing to be grounded. My PTT are hooked to the airframe under the control sticks and work fine.

FYI I put small quick disconnect plugs on my PTT wires where they come out of the bottom of the sticks. I used some connectors I had on hand from my RC aircraft stuff. This comes in handy if you ever want to remove yours sticks.

[jmodguy]

Shielding a PTT line adds unneccesary weight. When you push the button it grounds the line. 22 or even 24 AWG wire is fine. Remember, an ounce here, an ounce there, now you have a pound. Mic and audio lines can be 24 AWG shielded lines. Terminate the shields properly and you should be fine. I use heat shrinkable environmental terminations. Pricey but they will easily last the life of the aircraft.

[Shadowrider]

For the Garmin GTR-20/200 COM radio it says 22 gage wire is standard for everything except the power and ground wires. For my plane I used a common ground on the firewall for everything except my PTT switches. They don't carry any current and are just needing to be grounded. My PTT are hooked to the airframe under the control sticks and work fine.

FYI I put small quick disconnect plugs on my PTT wires where they come out of the bottom of the sticks. I used some connectors I had on hand from my RC aircraft stuff. This comes in handy if you ever want to remove yours sticks.

Could I run a 2 conductor 22awg wire for the ptt and then just take the one and connect it to the back of the connector from the one that needs to be grounded?

[PapuaPilot]

Yes you could, but it will add some extra weight. You don't need shielded wire for this. It just needs one wire from the GTR-200 to the PPT switch. The other side can go to your closest airframe ground. My opinion is that you only want to use shielded where it is called for because of the extra weight.

I used mostly 22 AWG where the wire wasn't shielded because of the added robustness, 24 ga. is pretty small and can easily break if flexed.

[Shadowrider]

Thanks Phil. Yeah I will use unshielded where I can. I just wanted two use 2 wire and run it back to the gtr 20 harness from the ptt and ground one side to the back shell and the other to pin 35 for the pilot.