The U.S. Federal Communications Commission (FCC) has granted a request from the American Radio Relay League (ARRL) to temporarily waive symbol rate limits for amateur radio communications used during hurricane and wildfire relief efforts.
Symbol rates are the rates at which carrier waveform amplitude, frequency and/or phase is varied to facilitate the transmission of information. Under current FCC rules, symbol rates applicable to high frequency (HF) amateur radioteletype (RTTY/data transmissions are limited to 300 bauds for frequencies less than 28 MHz and 120 bauds in the range between 28-29.7 MHz.
The ARRL submitted a petition to the FCC in 2016 to remove the symbol rate limitations due to advances in modulation techniques. While a decision on that petition is still pending, the ARRL also sought an emergency waiver of the symbol rate limits for licensees supporting hurricane and wildfire relief efforts via HF using PACTOR 4 modems, which permit relatively high-speed data transmission rates.
In an Order issued in mid-September, the FCC approved the temporary waiver requested by the ARRL expressly for emergency relief communications using PACTOR 3 and PACTOR 4 emissions within the U.S. and its territories. The period of the waiver is limited to 60 days from the date of the FCC’s order, September 17, 2020