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Dave S
12-23-2012, 03:21 PM
Got a question......what kind of wire have you used to connect a stick mounted PTT switch to the radio/intercom harness?

Will shielded Tefzel wire hold up to the constant flexing between the stick and wherever it is attached to the fuselage?

The spiral phone wire I originally used for the flexing portion of the wire run appears to be giving up.

Thanks,

Dave S
KF7 Trigear - Flying
912ULS Warp Drive

Av8r_Sed
12-23-2012, 03:26 PM
I used the shielded Tefzel allowing for a somewhat large bend radius where the movement is. It's been good for one season so far.

Dave Holl
12-23-2012, 04:38 PM
That's what mr Boeing uses!!!

Dave S
12-23-2012, 06:14 PM
Sounds good to me......Think I will be ordering up some shielded wire.

BTW...Av8r...how big of a diameter loop did you decide on?

Dave S

Dorsal
12-24-2012, 05:37 AM
I used regular 22 gauge Tefzel wire (no shield) with a generous bend. There is no signal on a PTT line so shielding is not necessary from an electrical point of view though may offer some mechanical advantage.

Av8r_Sed
12-24-2012, 11:54 AM
I have a radius of about 1 1/2 inches. I secured it with wire ties and put the stick through it's full range of motion while making small adjustments.

I used shielded on the PTT because the long line make a nice antenna when the buttons aren't pushed. I didn't want to channel noise right to my radio / intercom connector.

Maverick
04-06-2019, 10:15 AM
Anyone got a good picture of how you wired the PTT?

Also, did you run the ground back to the common ground, meaning one would need to run two wires through the control stick mechanism?

I was planning to use 20ga wire but could use 18. What's the recommendation on wire size.

jrevens
04-06-2019, 01:59 PM
You’ll need two wires. 20 ga would be plenty big. There is no current to speak of on this circuit.

efwd
04-06-2019, 09:07 PM
I ran all grounds to the same place behind the panel. I have not found any troubles with electrical as of yet. Man, do you know how relieved I am about that?

PapuaPilot
04-07-2019, 11:29 AM
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
04-10-2019, 04:11 PM
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.

jrevens
04-10-2019, 05:42 PM
I agree with Jeff. The only reason that you might want to use something a little larger than 24 GA, for instance, would just be for a little more robustness since this wiring will be subject to more movement than most of the other wiring in the aircraft, IMO. I believe I used 20 or 22 GA.

jiott
04-10-2019, 08:25 PM
I used 22 ga. non-shielded wire, but also put on some strain relief heat shrink in some critical spots because of the continual movement.

Shadowrider
07-08-2019, 04:17 PM
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
07-08-2019, 04:42 PM
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
07-08-2019, 09:58 PM
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.