--- In digitalradio@yahoogroups.com, "John B. Stephensen" <[EMAIL PROTECTED]> wrote: > > 47cfr97.307(f)(2) limits the bandwidth of all transmissions in the phone/image segments to that of AM or SSB communications quality audio which is usually interpreted as 3 kHz. > John > KD6OZH
Hi John, Digital Voice is "Phone" under FCC's definition. There is no bandwidth limit on a "phone" signal, implied or otherwise, for a digital voice signal. You either made an error or you are reading your FCC rules wrong. Here is what the rule actually says: ====== 97.307 (f) The following standards and limitations apply to transmissions on the frequencies specified in §97.305(c) of this Part. "(2) No non-phone emission shall exceed the bandwidth of a communications quality phone emission of the same modulation type. The total bandwidth of an independent sideband emission (having B as the first symbol), or a multiplexed image and phone emission, shall not exceed that of a communications quality A3E emission." ====== As you can see, that rule is for non-phone. Currently, the non-phone modes defined by FCC in those §97.305(c) frequency bands are "image" "data" "RTTY" "multiplexed emission" and "CW". If you read them carefully, you will find that the FCC rules are really unclear regarding any finite bandwidth limit for these non-phone modes on HF. That is because these ancient rules were written in the middle ages of digital signal technology. I will be happy to provide a examples of how the rules allow very wideband data bandwidth on HF, if you like. 73---Bonnie KQ6XA
