I know it's a little late, as the initial post on was over a year ago. Maybe it's so obvious that no one has pointed it out, but the circuitry Albert is describing is half built....
You can use your small AM rig as the PLL oscillator (it is already the 4046, 40103 and 4060 circuitry that Albert describes) and add to it an amplifier and modulator as described by Albert, just remove the analogue switch IC and take the carrier to your (newly built) amplifier and modulator.
Below is circuitry that Albert always seems to write about - (From Biascomms) - freely available online. You may wish to upgrade some of the transistors to more modern parts, instead of hunting for the old and possibly hard to find.
You can search 'medium wave alliance' in Google to find the details if you don't mind being bombarded with junk advertising and possibly worse.
Amplifier and modulator:
xmitter1c_pa&mod.gif
Audio processing:
xmitter1b_audio.gif
I do wonder about the interference potential of AM rigs to poorly screened (plastic cased) audio equipment though, which might end up being a problem.
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