Connecting Yaesu MD-100 microphone to the SM1000

[Steven P]

I've built this box to connect the MD-100 microphone to the SM1000 and retains the extra functions on the microphone.

Built using a dual RJ-45 socket wall plate.

MIC and PTT split out and go the SM1000 to chew on the audio, then the RJ-45 feeds the MIC and PTT back to the radio.

Question is - should I disconnect J3 to disable the microphone DC bias?

Thanks,

Steven P.

[Steven P]

Hi All,

I had thought the box in my previous post was working fine, but a closer examination revealed some odd behaviour. It tests good, but transmits rubbish.

Can anyone give me some advice on connecting a Yaesu MD-100 mic to the SM1000? I'd like to use my regular mic but also leave the SM1000 permanently inline. Refer to the diagram in my previous email.

I'm getting some weird results and I'm starting to think maybe it's not me.

I've configured the CN12 patch panel per my diagram, and when connected via the RJ45 to the transceiver it works fine. Connecting a simple external mic also works fine. Both SSB and FreeDV QSOs exchanged successfully.

But when I connect the MD-100 to the SM1000 via my patch panel I get odd results.

If I connect a headset to the 3.5mm RIG MIC port on the SM1000 I can hear the audio from the MD-100 fine. But when I connect the RJ45 to the rig only noise is transmitted.

Even weirder, sometimes the transmitted audio is just a buzzing sound, and that seems persistent across rebooting both the SM1000 and the radio. Even reconnecting the SM1000 directly to the rig via the RJ45 doesn't return it to normal function. But eventually *something* changes and it starts working again!

What am I doing wrong?

PS/ I've tried with and without JP3 to change the DC bias being sent to the MD-100, but that had no effect. I also thought it might be a problem with line vs. mic level, but I tried an attenuator and that didn't help, and it doesn't explain why the buzz is persistent when the device is cabled directly (until it mysteriously resolves).

PPS/ All other features on the MD-100 work fine when connected with the SM1000 in-line. i.e. PTT, freq shift up/down, and fast shift.

Many thanks,

Steven P.