On November 10th, [Theodore Rappaport] sent the FCC an ex parte filing regarding a proposed rule change that would remove the limit on baud rate of high frequency (HF) digital transmissions. According to [Rappaport] there are already encoded messages that can’t be read on the ham radio airwaves and this would make the problem worse.

[Rappaport] is a professor at NYU and the founding director of NYU Wireless. His concern seems to relate mostly to SCS who have some proprietary schemes for compressing PACTOR as part of Winlink — used in some cases to send e-mail from onboard ships.

The FCC proposal is related to a request by the ARRL (American Radio Relay League) seeking to overturn baud rate limits imposed in 1980 presumably in an attempt to limit signals eating up too much spectrum on the bands. However, PACTOR 4 — specifically mentioned in the proposal — is narrow bandwidth but capable of sending 5,800 bits per second and is thus not permitted on amateur bands. The ARRL argues that this is actually preventing efficient use of the bands. Keep in mind that while PACTOR is well-known, PACTOR-II, -III, and -IV are proprietary and generally not decodable without using an approved modem.

It doesn’t seem especially related to us that upping or removing bandwidth limits would necessarily result in national security problems per se. First, the airwaves aren’t exclusively American. So while the FCC can control radio operators in the United States, that isn’t the entire problem. Second, enforcement is lax but doesn’t have to be and anyone who really wants to compromise national security will probably flaunt the law anyway. And finally, anyone who really wants to send secret messages can probably do it over other means and/or use steganography to conceal their encoding.

So we aren’t sure what the real point to the filing is. Sure, sending encoded messages on the ham bands is against the rules, which ought to be better enforced. If PACTOR-IV is going to be used by hams it ought to be open. But upping the baud rate limit doesn’t prevent or allow this from happening. Is it really a national security risk? If it is, it seems to us only minor. What do you think? Let us know in the comments.