How might this circuit be modified to drive it with an input audio source of less than 80mV Peak to Peak?

Possibly adding another stage with a 2N3904?

Would like to:
Keep it analog
Have a pot to adjust the input trigger level.

 

For a signal that small, a comparator or opamp will give you much more reliable control. Are IC's allowed in the design? Is this for school?

ak

 

For a signal that small, a comparator or opamp will give you much more reliable control. Are IC's allowed in the design? Is this for school?

ak

The design is Ham Radio, anything components can be used, just looking for a solution.

 

Try this:

 

Try this:
View attachment 184705

The V1 & V2 symbols, do they represent voltages?
Is V1 a 5 volt source and V2 my audio input?

 

Is V1 a 5 volt source and V2 my audio input?

Correct

 

Correct

Appreciate you drawing this up.

Any way to modify the 5V portion to work off 12vdc?
Plan is to power this with a 12 volt battery.

How about a 7805 and filter it for the 5v?

 

Any way to modify the 5V portion to work off 12vdc?
Plan is to power this with a 12 volt battery.

It should work with 12V

Connect this circuit to your circuit with the coupling cap