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DYNON INTERCOM ISSUE

RV-4

Well Known Member
Hello All

I’ve been in the process of installing ‘’a new to me ‘’ GNS-480 as a second COM with an SL-30 and a Dynon Intercom and due to space constrain I was planning to use a switch to select either Com# 1 or Com # 2..

But last night, I read again the installation of my Dynon Intercom and it says that to do so I will need radios with built-in Transmit Interlock.. The problem if I’m right is that the GNS-480 & the SL-30 don’t have Built-In Transmit Interlock ( as per Garmin Support ) but rather a De-Sensor of some kind that reduce one radio’s power when the other one is transmitting....

I’m curious to know because right now when both radios are ‘’ON’’ I get a scratchy noise and when transmitting with the SL-30, the GNS-480 is also transmitting.. When transmitting with the GNS-480, the SL-30 does not transmit..

When either radio is ‘’OFF’’ , the other one is working normally..

The wiring harness is OK as far as I know ( I will check it again ) so maybe I have a faulty Intercom ??

Do you guys know if there is such a thing as a Transmit Interlock that can be added to the intercom to make this thing works..

Any inputs you may have will be welcome as I’m running out of ideas..

Thanks

Bruno
[email protected]
 
This is not about Transmit interlock.

As you state, when transmitting on the SL30 the 480 also transmit. You have your PTT connected to both radios - so both transmit.

The Comm 1, Comm 2 switch needs to also switch PTT between the two radios. As you have the problem when transmitting on SL-30 but not when transmitting on the 480 I’d guess you wired this switch wrong, or perhaps you have a couple of the switch pins shorter together.

Carl
 
Some radios do have a "transmit interlock" feature. You run the PTT line for radio #1 to the interlock line for radio #2. This mutes (either totally or partially) radio #2 while #1 is transmitting, so you don't hear yourself (possibly distorted due to the very strong signal) over #2. But most pilots I know accomplish the same thing, by just turning down the volume on #2 when transmitting on #1. After all, if you call the tower on #1, and just as the tower replies, you don't want to hear someone on radio #2 making the tower hard to understand.
 
Dynon Intercom Issue

Carl,
When I switched radio using the installed switch, it works as it is supposed to so I would say that is wired properly.

I have checked all wires from both radios for a possible ground and didn't find any but I will check again for a faulty pin which could happen.

BOB,

''most pilots I know accomplish the same thing, by just turning down the volume on #2 when transmitting on #1',

That is what was suggested to me today by Dynon Support..They say that even tough the Intercom could work with two radios, it is more of a single radio type intercom..

Another issue that I have with the SL-30 only is with the radio installed in the Console ( my radios are mounted in a center console between my legs just above the battery compartment ) is when selecting a frequency in the Stand by side of the radio and moving it to Active ( EX 123.45 ) The frequency will change on its own to for example 123.42 ....

It does that only when in the aircraft and when connected to the Intercom...
I tried it in & out of the console outside of the aircraft using a battery hooked up to it and it works flawlessly...:confused:

Any idea what might be causing this....Wiring issue I would guess but which one as I checked them all a zillions times:(

I do appreciate you guys helping out

Thanks

Bruno
 
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