[Gonset] Gooney birds to NBFM?

[Mike Clarson]

I converted a Comm IV to FM transmit (used slope detection for RX). ARRL
handbooks had a circuit for a 1 tube reactance modulator. I soldered a tube
socket to some bracket near the crystal and wired in the modulator. Rewired
the meter switch to route speech audio between the AM and FM stages. Worked
very well, and is 99%  reversible (small solder stain left). Sorry I cannot
help more as all this is from memory. Should work on the COMM II and III
also. I chose this method over varactor on the crystal because using FT-243
crystals, deviation changed from crystal to crystal. Using the 1 tube
modulator, it would work with all my crystals and the VFO. Good
luck. --Mike, WV2ZOW