100k and 300k with AC125. Here I used an ‘equivelent’ NTE102A.
680k RF resistor AF126. Used ‘equivelent’ NTE160
In process of parameterizing these transistors. The AC125 and AF160 can be found and I may ebay some to see how close they are to the NTE’s. NTE’s were easier for me to get.
My tuner block seems to have a measured resonance in the AM band but I have not had much luck with the three transistor AM radio. Amplifier sections seem as though they are working. I need to spend more time first calculating what the circuit gains should be and then measuring on the bench. Could simply be that I have poor reception and this amplified crystal radio is hard pressed to bring anything in without a mile of antenna.
That’s about it for the actual build. I am an avid wood worker so machining the parts was pretty straight forward. Still, why anybody would do this I don’t know. Actually I do, because I can share this with others and perhaps spark an interest in engineering and building.
I will start with circuit demonstrations tomorrow.