Control of Co radio transmitter auldio in DUAL COM installs

[cbretana]

I apologize for my inability to get this straight. I have had several phone conversations about this with Dynon tech representatives, but when I try to match up what I took away from those conversationls with the documentation in the installation manual, I keep getting mixed up.
Would a Dynon tech confirm for me the following for the logic controlling the output on pins 15 and 25 on the SV-COM-INTERCOM DB25 connector to the SV-INTERCOM-2S intercom?

I believe the output on both pin15 and on pin 25 use the same logic. It is, (for both pins), either the input on pin 23 [FCP Mic audio], or pin 3 [ RCP Mic audio], depending on whether pin 10, (Pilot PTT), or pin 16 (CO-pilot PTT), is shorted to ground.

Is this correct?

Thanks in advance.

 

[Rhino]

Does the manual not answer that question for you? If not, I'm not sure what you're asking.

4.9 Radio Push-to-Talk (PTT) Behavior and Priority

When the pilot or co-pilot presses a PTT switch, only the person pressing their PTT is heard over the radio.

If the pilot and co-pilot PTT buttons are both depressed, the pilot PTT takes priority. Only the pilot’s voice is transmitted over the radio. Additionally, the pilot PTT will take priority from the copilot even if the co-pilot PTT is already depressed.

 

[cbretana]

Rhino,

Thanks for your insight, I did see that entry in the manual. However, my issue is a bit more complex.
That paragraph is about what shows up on your headphones, and assumes that you wire everything in accordance with whatever scenario that paragraph was written to address (Single COM Transceiver using Dynon ICS)

It does not address what happens for any other non-standard scenario, like Single COM Transceiver using third-party Audio panel, Dual Transceivers using Dynon ICS with SPDT COM Transceiver selector switch, Dual Transceivers using third-party Audio panel with SPDT COM Transceiver selector switch, Dual Transceivers using third-Dynon ICS with Separate SPST PTT push button switches for each cockpit/COM Transceiver, etc. etc.

I know how the system should work for the standard simple configuration, but I am using separate PTT switches for FCP COM1, FCP COM2, RCP COM1, and RCP COM2, and I am using the Dynon ICS, not a separate audio panel, so I need to understand how the logic inside the Dynon ICS, based on the inputs to the PTT pins (pins 10 and 16) generates the signals on the Pins on the SV-pins on the Dynon SV-INTERCOM-2S, wired in accordance with Figure 6 on page 16 of the Install manual.

 

[Rhino]

That's not about what goes to your headphones. It's about which cockpit mic audio goes to the radio to be transmitted. But I think I see what you're getting at. You're using multiple standalone switches in place of what an audio panel would do. As I recall, the the size of your cockpit would necessitate the fewest 'boxes' possible.

The 'logic' is simply what that paragraph says. The audio goes out to radios based on who clicks a PTT, and the pilot takes priority if both get clicked at the same time. It appears you want both cockpits to have individual radio control, i.e. one can use Com 1 while the other uses Com 2, determined by cockpit switch positions. Correct me if I'm wrong.

The problem is mixers. The mixer in the 2S assumes only one radio at a time is being used. One could say the 2S is only designed for one radio, and they just tacked another output in there for good measure. In reality, the 2S isn't an audio panel, and can't function as one. External switches have to be used to get audio panel type of function. But audio panels also contain mixers, and you can't duplicate that function with simple switches. You have to put simple mixers somewhere, and get creative with wiring. Fortunately, they don't have to be panel mounted.

I've helped people with similar projects here before. I'll have to search for those threads. But we're looking at some variation of the concepts below I think.

The exact solution for you would depend on your equipment, and your specific desires for it.

 

[cbretana]

Everything in your post is only true if you wire it up the way it requires, to wit, with SPDT COM1/COM2 selector switches.
The pinouts on the SV-INTERCOM-2S DB25 Connector are designed and implemented to conform to that design. The manual even has a diagram (Figure 10), depicting it, as both of your attached files also show.
Again, as I said above, I am using separate SPST PTT switches, one for each transceiver, in each cockpit.
Please, if your response is just to do it the way the installation manual lays out, thanks, but that's noI the way I want to do it. I don't want to have to move two switches (or first check a selector switch) before I transmit, for every transmission. It is possible to wire the system with the existing Dynon intercom, (and a few additional relays), to do what I want. I just need to confirm what the output on a few specific existing pins on the ICS is.
One clarification you asked is:

"It appears you want both cockpits to have individual radio control, i.e. one can use Com 1 while the other uses Com 2, determined by cockpit switch positions. Correct me if I'm wrong."

This is indeed what I am hoping to do. My primary concern here is making sure that for each pilot, if they push their PTT button for one of the COM transceivers, that only the audio from their microphone will be transmitted.

I am implementing the logic to ensure that the pilot PTT (transmit) button will override the co-pilots for each transceiver (attached).

But another concern, (implied by your question), is whether both transceivers should be allowed to transmit simultaneously. I know that each transceiver needs its own separate antenna, but I am not sure how far apart these antennae must be to allow them to transmit simultaneously. Do you know? I am installing all this in a canard aircraft and the two antennae are mounted inside the vertical winglets (about 26 feet apart). Far enough?

 

[Rhino]

Please, if your response is just to do it the way the installation manual lays out, thanks, but that's noI the way I want to do it.

Those diagrams don't match anything in the manual. They're very customized, and they're just examples of what can be done with the concept, as I stated. They weren't intended as a specific solution for you. As I stated in my last sentence, the exact solution for you would depend on your equipment, and your specific desires for it. I was simply offering to help with a custom solution for you, but apparently you missed that.

As for the antennas, the general rule is 1/4 wavelength separation, which is about 19 inches for VHF radios.

 

[cbretana]

Thanks anyway. I appreciate your offer, but I don't think you would be able to help me.