14 Mar
2024
14 Mar
'24
10:32 p.m.
On 3/14/24 21:34, Dave Schmidt wrote:
Calli, Here's that QST article with the one transistor mic amp. Dec 2018 QST article.
The non-phantom-power schematic in figure 3 won't work as shown. The mic+ line to the transceiver will have no audio as it's at the same AC potential as the +8v supply. You need a series resistor between the +8V line and the junction of C2 and the collector. I'd start around 5K. Higher values will give more gain up to a point.
Also, C2 is drawn backwards. The curved (negative) terminal should be towards the transceiver mic line.
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Jay Hennigan - jay@west.net
Network Engineering - CCIE #7880
503 897-8550 - WB6RDV