This gave me quite a fun time the last few hours. Most annoying to me are the discrepancies to the sim + what I though to be logic and what I measured.
Anyway first:
All resistors and capacitors are actually the values in the sim (eventhough all are through whole, all leads are less then 1-2mm).
The choke is just a big inductor I had laying around but it should do.
The resonator coil is selfmade and then hooked up to a 40MHz sin wave with a resistor in series to roughly confirm the 250nH.
The transistor is a MMBTH10 (Diodes).
The board layout was just quickly drawn and etched on single sided clad and basically consists of rectangles and one bit longer line but with no respect to impedance (not longer than 1/10 lambda tho).
So now to what works as predicted:
The current reading is just off by 0.5mA which I think to be fine considering tolerances.
Also the frequency considering hugh parasitics of the cheap components could be fine (measured 92.3MHz on the freq counter).
Now what doesn't fit:
First I got to say that I just have one of those cheap ass 60MHz probes which could definitely have effect on the results.
So the measured output voltage pk to pk is 2,40V which is not even close to what the sim gives me.
Also the output impedance, which I thought was determined by the collector resistor on CE configurations, was more like 166 ohm when I measured open VS loaded output and put it in the formula.
Anyway the signal quality is actually alot better than what EC gives me. I mean it's not a perfect sine, but alot better than in EC. It just jumps around sometimes but that might be due to the triggering.
Then looking at FFT the harmonic content of this oscillator:
There is a second big spike at 108Mhz which is roughly 20dB lower than the 92Mhz one. Then there are harmonics at 183MHz and 192MHz which are about 25dB lower than the main 92Mhz one. And there are more harmonics at 9MHz and 18MHz also about 25dB lower.
Now what isn't supposed to be:
So everywhere I measure on the ground plane I get the signal with roughly 500mV pktpk. Even at the connection of my power supply.
Also connecting the probe to the output vs having it looped as an antenna changes the frequency of the circuit by a few MHz.
And then when I connected the probe, the voltage displayed on my power supply jumped up by almost 1V. I thought this to be due to reflections and standing waves and thus added the 500 ohm load. That actually helped alot but sometimes it still changes by ca 200mV.
Well maybe this helps someone somehow or someone can somehow help me.
