amdx wrote:
Hi All,
Please see pictures and diagram at ABSE.

I duplicated a circuit for someone because they got a bad
output waveform.
Well I did too.
Capacitor = air variable set at 365pf
inductor = 41uh aircore
With freq set at 1.3Mhz I have the voltages as follows;
Collector - 11.8vdc
Base - 3.1vac riding on top of 3.2vdc
Emitter - 2.5vac riding on top of 3.9vdc (Don't be critical, it's not ac
if it sets on dc)

As I shift up in freq at about 2.7Mhz the voltages jump.

Capacitor = air variable set at 40pf
inductor = 41uh aircore
Freq = 3.7Mhz
Collector - 11.8vdc
Base - 10vac riding on top of 1.8vdc
emitter - 1.1vac riding on top of 9vdc

The base waveform in both senerios is much more sinewave (ish) than the
output.

Any ideas how to get a decent waveform? The next step will be a buffer,
but...

Note; original schematic used a crystal, I substituted the LC. Could this
be the
cause of the distortion?

Thanks, Mike

Mike ,

What is ABSE? Need a circuit before comments can be made.

Roger