Bill,

Good to hear that you tamed the oscillation, but the 560 ohm load resistor
seems a bit severe...have you tried something in the few kohms range?

50 mv out of the mixer on a 'weak' station sounds pretty good. What is the
combined gain of the two IF stages? Are they possibly overloading ?

Also, how are you coupling the antenna into the mixer?

Joe
W3JDR

wrote in message
oups.com...
I sucessfully hooked up two stages with no oscillation problems. I
added a 560 ohm load resistor across the output winding of the first
stage. The LO oscillator is a separate circuit (JFET) and there are no
physical connections from the the oscillator to the mixer stage. It
seems to mix and produce the IF from just the radiation from the LO
capacitor to the station tuning capacitor.

The IF modulated output is about 2 volts p-p on a strong station, 600
mV on a average station, and only 50mV on weak stations.

It's almost usable, but not quite. I need to raise the weak stations
another 12 dB or so. Also, the LO oscillator is leaking into the output
at the high end of the band. I get 100mV of noise from the LO toward
the high end.

Is it a good idea to try and raise the gain of the 2 existing stages,
or try to add a third stage to raise the gain?

I've noticed some transistor radios use only one IF amplifier stage
while others use 2.

What are the advantages of the third stage if enough gain can be
obtained from just 2?

-Bill