I was thinking of using an alternate microphone with the DUO.  Has anyone done this?  I have a Heil noise cancelling with a PTT switch.  I could wire an RJ-45 connector if the element is compatible.  Any help here?

I have a Kenwood MC-60 desk mic I use with the FDM-DUO. 

I added a new cable with RJ-45 connector to the MC-60 and also a toggle switch. The switch moves the audio and PTT between the existing connector and the new RJ-45 cable. 

Using the switch I can move the MC-60 between my TS-2000 I use on 6M, 2M and 70cms and the FDM-DUO. The MC-60 includes a mic-preamp. This can run from internal batteries or an external supply on the transceiver interface. I get best results with the FDM-DUO with the pre-amp in the mic on. I use the +8V supplied on the RJ-45 to power the pre-amp. The TS2000 also provides a suitable supply voltage so the toggle switch switches this also. 

I find the DUO always a bit 'weak' for SSB 'talk-power' so tend to use 12dB of gain in the 'mic amp' settings in the DUO menus. 

In the my home station I use the DUO exclusively with the FDM2 software. I am able to get the audio from a mic connected to the RJ45 into my PC as a sound source. I then use a piece of software call 'Voicemeter Potato' to add compression and processing to the desk mic audio before sending it to the FDM-DUO over the TX audio USB interface. This works well and increase the 'talk-power' of my SSB signals on busy bands. 

Elad tell people on here that using the FDM MIC audio into a PC does not work but it most defiantly does and I use my radio in this way by default everyday. Just a matter of getting the USB ports to enumerate in the correct sequence.

Hope this helps

Matthew g6wpj

I use a Heil Pro7 headset with a dynamic insert with +12dB boost and compression set to 8 and that seems to be OK.  It should really be an electret, but with the boost and compression, it works OK.  If I was buying a new mic or headset, I'd get one with an Icom-compatible electret insert.

Matthew is spot on about the enumeration, and despite general Windows weirdness, the mic input to the DUO does indeed work as a source for Windows audio applications (except when it doesn't, which is *always* during a contest or when there is a huge tropo opening or I'm in a hurry, or there is some fabulous DX on- it always works when I don't need it to)

Neil G4DBN

After some trial and tribulation, I succeeded in getting my headset to plug into the radio and actually work.  It would seem the wiring solution that I chose for the connection to the RJ45 connector was difficult to work with (stranded wire) as it was not standard solid CAT5 diameter wires.  It took me about 4 hours of trying to get a connection to both the PTT switch and microphone that actually worked.  And, needless to say, I have done about a hundred RJ45 connectors in the past.  Oh, well.  My headset works just fine now.  Thanks for the replies.