Cecil wrote:
"Is NBFM still allowed?"

Interesting question but I was responding to the question in the thread
tille.

FM usually occupies about twice the bandwidth of AM. Spread spectrum
ordinarily occupies more bandwidth.

Spread spectrum was patented by Nikola Tesla in 1903. FCC now codifies
rules for spread spectrum in Wi-Fi, Bluetooth, cordless phones, etc.

Terman says about twice the bandwidth is required for FM as compared
with AM on pages 589 and page 590 of his 1955 opus.

The signal for spread spectrum is a form of FM but usually the signal is
transmitted on a bandwidth considerably larger than the frequency
content of the original information says Wikipedia.

Best regards, Richard Harrison, KB5WZI