I find nothing in Part 97 which would preclude ACSSB, as it appears to meet the definition of "phone," but I do recall some debate at the time on whether the audio frequency inversion scheme/pilot tone was a form of scrambling/encryption, which would have made it illegal on the ham bands. The main benefit of that inversion was to preserve low-frequency audio response which normally is tough with a filter-based SSB exciter, and put the pilot tone at a frequency where it was easily processed and filtered, but hams are accustomed to narrow audio bandwidths and "ducks talking," and there was no compelling reason to play with ACSSB.
To some extent, ACSSB was simply the worst of all worlds, like NBFM with more ignition noise and companding artifacts, or SSB but restricted to channels. It made sense on paper as an analog bandwidth conservation tool compared to NBFM, but sounded really bad in areas of marginal signal, and who's still developing analog techniques these days? One reason for lack of interest in the mode I haven't seen mentioned was the incredible hostility generated among hams by the taking of 40% of the 220 MHz band to make commercial ACSSB happen. Just the mention of ACSSB at a club meeting would result in spontaneous aneurisms, even among hams who'd never operated on 220. Nobody wanted to be associated with ACSSB. We were too busy boycotting UPS! 73, Paul, AE4KR ----- Original Message ----- From: n0fpe To: [email protected] Sent: Thursday, November 12, 2009 5:34 AM Subject: [Repeater-Builder] ACSSB One thing to remember. Amatuers are NOT authorized to use ACSSB above 30mhz. Please check part 97 for the exact "modes" we are able to use. heck if we were there would be tons of ACSSB repeaters already modified into the ham band.
