The Heil headset works fine here with both my FT-60 and FT-70.

Make sure the plug is firmly seated in the jack and the mic element is close to your mouth.

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Also, the two ends of that tiny barrel-shaped mic capsule are 180 degrees out of phase, to help cut down on background noise. Meaning, if you talk into the side of the barrel, between the two elements, you will sound thin and quiet.

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