Unstable Oscillations

 

For whatever reason, the MMIC amps in the receiver are super unstable. They have 2 states, oscillating wildly or not working at all. This is a real head scratcher, because the exact same circuit using though hole parts was super stable. The other thing is, if i stick my finger on the input cable, it becomes stable again. Go figure.

OK I got it sorted out and now its stable. The issue was the limiting resistor  R9 was to low a value. I am not sure why the through hole version was happy with 60ohms and the SMD version wanted 150ohms. But, either way, I learned a valuable lesson here with MMICS, if they are going bonkers and oscillating wildly, cut their current back by increasing their limiting resistor.

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