PTT Wiring

sjrossi

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Mar 15, 2018
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Not exactly sure how to wire my PTT circuit and would appreciate comments. Have all new Skyview system, including one SV-Com-C25 and SV-Intercom-2S. Also, using the factory Intercom harness. I think I have to run the PTT wire all the way from each of the Mic Jacks in the panel back to the respective stick grip. My question is, is there really a difference between the pin 1 ground and the pin 2 mic ground, on the intercom? When I test for continuity between those two wires, I have continuity. So, can I ground the PTT switch locally, near the control stick, or do I have to run a dedicated ground wire back to the respective mic jack?
 

sjrossi

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Mar 15, 2018
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Got it. I just wondered why Dynon provided a separate mic ground (pin 2 on the intercom connector) vs the primary ground (pin 1). I'll plan on grounding the PTT circuit locally near each of the sticks. Thanks.
 

Raymo

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Got it.  I just wondered why Dynon provided a separate mic ground (pin 2 on the intercom connector) vs the primary ground (pin 1).  I'll plan on grounding the PTT circuit locally near each of the sticks.  Thanks.

In general, you want all audio/com related grounds to share a common point. PTT, though, is one that shouldn't matter, IMO. That said, sticking with the schematics will help with troubleshooting down the road when you forget how it was done :)
 

breister

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Apr 6, 2018
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PTT just needs to sense ground, when pushed. Grounding locally to the stick is acceptable.

Unless you fly a fiberglass plane and the stick has not connection to aircraft ground!!!

To avoid electrical noise, Ray was right the first time - in an ideal world all grounds route back to the same point (or along an elongated ground strip). Even a PTT can cause gremlins if you "just pick a handy grounding point" which happens to be a conduit to create some odd loop elsewhere.
 

Raymo

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PTT just needs to sense ground, when pushed. Grounding locally to the stick is acceptable.

Unless you fly a fiberglass plane and the stick has not connection to aircraft ground!!!

I apparently was not clear. I didn't mean ground to the stick but ground near the stick is acceptable. Obviously, this can be done in non-metal aircraft.
 
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