Anybody have experience w IC-A220 Comm from Icom?

DKirkpatrick

DKirkpatrick

Pre-takeoff checklist
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DKirkpatrick
Looks like a good, new radio.
Not used to "new"... but gotta believe new would be nice in an old airplane.
But of course, these don't have the history of BK, Apollo, Garmin...
thanks

dan
 
I have one, it works great. Some fumble-fingered installers have a problem with the install. Did it myself.
 
The "keyline" for the A220 looks for a very low resistance "ground" signal for its PTT circuit. This can cause problems with some intercom/audio panel configurations that still show a small amount of resistance on the keyline when the PTT is depressed. The fix is to have the PTT switch wired to a relay that provides a chasis ground to the radio, rather than internal ground provided by the intercom or audio panel. If you do use a relay in the PTT circuit, make sure you also use a flyback diode.
 
Have had an A210 for many years and it’s been great
 
Question on interfacing the ICOM A220 to a GMA340. PTT does not allow Mic to work, although I get a click and other pilots say I am present but no audio. I saw where some folks place a relay into the circuit to ground the radio rather than using the circuitry of the GMA 340. This is my Com2, the Com1 (MX170C) works fine. Does anyone have a schematic of where I need to wire in the relay? I saw some posts out on Aircraft Spruce stating that this was a work around, but did not see any specific instructions.

Thanks.
 
Dave Richers said:
Question on interfacing the ICOM A220 to a GMA340. PTT does not allow Mic to work, although I get a click and other pilots say I am present but no audio. I saw where some folks place a relay into the circuit to ground the radio rather than using the circuitry of the GMA 340. This is my Com2, the Com1 (MX170C) works fine. Does anyone have a schematic of where I need to wire in the relay? I saw some posts out on Aircraft Spruce stating that this was a work around, but did not see any specific instructions.

Thanks.
Click to expand...

I can't say if this is your particular problem. But, there is a known problem with the A220 and some intercom systems.

The relay is to put the radio keyline to a ground potential. The A220 is looking for 0 volts on the keyline. But, a couple of milivolts dropped by a diode in the PTT circuit in some existing intercoms will prevent the keyline from activating the A220 transmitter. A good example of the workaround is on the the Sigtronics website here:

https://www.sigtronics.com/_pdf/air_pdf/air_intercom_pdf/Radio_Keyline_Mod.pdf
 
Personal experience with Icom brand ham radio equipement has been almost all good, having used several of their radios for HF and VHF. Only 1 exception - a 2M FM mobile unit that spent too much time in the sun on the dash of my car - it degraded, but still usable. Other brands of ham gear I've used have had shown issues, reliability wise.
 
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