Pactor was FSK with a 100% duty cycle (or peak to average power ratio - PAPR), but Pactor-III is OFDM which has a PAPR similar to SSB and much less than SSB with RF clipping so I don't see how its any worse than digital voice or SSTV. Were the two stations in the automated segments fighting or just transferring data in both directions? I just don't see the threat from automated Pactor stations as they are legal on every amateur frequency outside the U.S. and they haven't taken over there.
73, John KD6OZH ----- Original Message ----- From: KH6TY To: digitalradio@yahoogroups.com Sent: Monday, February 22, 2010 00:04 UTC Subject: Re: [digitalradio] A closer look at ROS]] John, The principle of regulation by bandwidth that was fostered by Winlink through the ARRL was that any mode would be allowed in a particular segment of bandwidths as long as the bandwidth was the same or similar. No restriction on content or operating methods.This would have meant that the messaging stations would have full access to all of the phone bands with no restrictions. For example, Pactor-III which has about 100% duty cycle (modulation), compared to 30% average for uncompressed phone, could easily displace any phone QSO and the phone operator would not even be able to identify the interfering station because he would not be operating Pactor-III. The result would have been dominance by messaging systems with no place left to have phone QSO's without the possiblity of being interfered with by an automatic messaging station. Messaging stations are run with ARQ so they fear competition of their own kind and you can often see two automatic stations battling automatically for a frequency. As a result they want to spread out over the band as much as possible to avoid interference from each other instead of sharing frequencies on a first-come-first-served basis like everyone else.