Converting an 11m CB to Amateur Use: 10m Fun with General Electric (Part 2: Power Out and AM Mod Depth)

Quick update: testing TX power without a RF power meter.  This is easy.  Hooked to a 50 ohm load (Termaline resistor), clipping onto the output jacks with a scope reveals the AM carrier (unmodulated):

That's channel 1.  The top of the range - channel 40 - is identical:

So Vp-p = 38.4 V.  (38.4)**2/(8*50) = 3.68 W in the RMS sense.  Since this is supposed to be a 5W radio, it's close enough to declare the finals are working.

How does the modulation look?  Here's an unsophisticated test: pump a 400 Hz tone from a cellphone audio generator app into the microphone, held up to the speaker.

Looks pretty deep modulation to me - 80%? 90%? - and no distortion/crossover.  Anyhow, the mod circuit is working fine as well.