Sigtronics and ICOM A220 install question?

[macflyer]

Hi, I installed and Sigtronics 200S intercom and a ICOM A220, but have erractic to know TX? I see they recommend a relay? What type of relay and where can I purchase one? Not to familiar with wiring. Thanks for the help!!

 

[fl-mike]

single or dual PTT setup?

 

[macflyer]

single or dual PTT setup?

Dual

 

[N804RV]

A220 key line circuit looks for a dead short, 0 volts difference of potential. Sigtronics uses diodes in the PTT switching which results in a few millivolts being present on the key line. You must do the PTT workaround relay.

It's just any simple relay that will work with 12vdc coil voltage. This is the one I used. https://a.co/d/03kdD97 .

For wiring just follow the instructions on the Sigtronics page and don't forget the diode across the coil leads (pay attention to polarity). I used a 1N4001. soldered pigtail wires and diode to the relay. potted the terminals with gray RTV so that only the 4 wires stuck out and then used an Adel cushion clamp to secure the relay to the anchor strap on the back of the tray.

Did this install about 5 years ago, as far as I know it's still working fine.

 

[N804RV]

Here's a quick line drawing. It really is pretty simple. Hope this helps.

 

[macflyer]

A220 key line circuit looks for a dead short, 0 volts difference of potential. Sigtronics uses diodes in the PTT switching which results in a few millivolts being present on the key line. You must do the PTT workaround relay.

It's just any simple relay that will work with 12vdc coil voltage. This is the one I used. https://a.co/d/03kdD97 .

For wiring just follow the instructions on the Sigtronics page and don't forget the diode across the coil leads (pay attention to polarity). I used a 1N4001. soldered pigtail wires and diode to the relay. potted the terminals with gray RTV so that only the 4 wires stuck out and then used an Adel cushion clamp to secure the relay to the anchor strap on the back of the tray.

Did this install about 5 years ago, as far as I know it's still working fine.

Thanks! I will try and do the connections!

 

[macflyer]

I ha

Here's a quick line drawing. It really is pretty simple. Hope this helps

I have two push to talks. Do I need two relays?

 

[macflyer]

Here's a quick line drawing. It really is pretty simple. Hope this helps.

I have two push to talks, do I need two relays?

 

[N804RV]

I ha

I have two push to talks. Do I need two relays?

No. The Sigtronics intercom uses diodes internally to control the bias on a circuit that determines whether the pilot or copilot's PTT controls the radio key line. With the relay installed, the radio's key line will no longer "see" those diodes. It will only see an ON or an OFF. It doesn't know who pushed the button.

 

[macflyer]

No. The Sigtronics intercom uses diodes internally to control the bias on a circuit that determines whether the pilot or copilot's PTT controls the radio key line. With the relay installed, the radio's key line will no longer "see" those diodes. It will only see an ON or an OFF. It doesn't know who pushed the button.

Thanks! I asked, because my co pilot push to talk in my RV4 is not transmitting when pushed.. I have checked and doubled check the wiring. Next is the push to talk switch itself. The relay is installed and works on the pilot side!

 

[N804RV]

Did the copilot's PTT work before, or has it never worked right? Is the RV-4 the airplane with the Sigtronics intercom and the IC A220? What other radios do you have (com & nav)? What audio panel do you have?