I figured I had trouble in the mic amp when I saw the low voltage gain. ?So I removed C106, and the voltage gain jumped to 10. The two diodes in the modulator give a very low impedance load to the mic amp. ? Still 200mv after the fix. ?I found the voltage gain through those BiDi RF amps to be surprisingly low as well, will have to revisit this. ?Perhaps simulate in LTSpice. ?Am seeing on the order of 5W out, so likely all is well with my rig. ?My measurements should be taken with a grain of salt, they were made rather quickly. ?Should include DC levels too. ?But it's a step in the right direction.
Jerry, KE7ER
On Wed, Mar 1, 2017 at 01:29 pm, <vk4bap@...> wrote:
The mic amp gain is then somewhat higher than your 200mv at C107 would imply,
?
