30m Oscillator (Night 7)
My Boonton 4200 power meter showed up today.
I went back and remeasured the circuit on the meter. I originally thought that I was
getting 10-12 dB of gain. With the Boonton I am measuring about 14.6dB of gain from
the circuit with about 35mA of consumed power.
I tried several PN2222 components and the range was all over the board. Gain was pretty
close but the power consumed was pretty wild by a factor of 3x. (I threw the the ultra
wild part away.) I also substituted a 2N3904 into the circuit. It had almost exactly
the same gain and power consumption model.
It seems like I should be able to get this much gain with 1/3 of the power consumption.
I am not sure how to do that as balancing the base against the emitter and collector
for peak gain and minimal consumption is pretty challenging. I suspect that I can
tweak the resistors a bit more but this would be easier with a dual channel power
supply with digital feedback to rough out the voltage and current values while watching
on the oscope & power meter.
---Hmmm I am still kicking myself for not buying that bench power supply that I was
eyeing during the hamfest last Saturday. I might have to resolve that via eBay or
the up coming Midwinter Madness hamfest in Buffalo.
I went back and remeasured the circuit on the meter. I originally thought that I was
getting 10-12 dB of gain. With the Boonton I am measuring about 14.6dB of gain from
the circuit with about 35mA of consumed power.
I tried several PN2222 components and the range was all over the board. Gain was pretty
close but the power consumed was pretty wild by a factor of 3x. (I threw the the ultra
wild part away.) I also substituted a 2N3904 into the circuit. It had almost exactly
the same gain and power consumption model.
It seems like I should be able to get this much gain with 1/3 of the power consumption.
I am not sure how to do that as balancing the base against the emitter and collector
for peak gain and minimal consumption is pretty challenging. I suspect that I can
tweak the resistors a bit more but this would be easier with a dual channel power
supply with digital feedback to rough out the voltage and current values while watching
on the oscope & power meter.
---Hmmm I am still kicking myself for not buying that bench power supply that I was
eyeing during the hamfest last Saturday. I might have to resolve that via eBay or
the up coming Midwinter Madness hamfest in Buffalo.