I found on the net the schematic of icom's HM-7
handy powered microphone.
I can't unterstand if one of the three resistors value
is 18KOhm or 1.8KOhm.
73
SV2BFI
Looking at the schematic it is difficult to tell.
I believe it is 1.8K.
1. compared to the 10K number the spacing is slightly wider between the 1 and 8.
2. looks to be a hint of a period between the 1 and 8.
3. resulting bias on the transistor is more in line with 1.8 than 18.
Mike