08/28/2019

In an effort to more effectively address HF digital technology issues, ARRL President Rick Roderick, K5UR, has reactivated the ARRL Board of Directors' HF Band Planning Committee. The six-member panel, chaired by First Vice President Greg Widin, K0GW, will primarily focus on spectrum allocation issues that have gained increased visibility with discussions on accommodating automatically controlled digital stations (ACDS) - many employing Winlink[1] email. The committee will also discuss operating frequencies for FT4, FT8, and other digital modes. Widin says the committee will meet next week to chart its course. Reactivation of the HF Band Planning Committee came out of discussions during the July 2019 ARRL Board meeting.

"ARRL is not trying to shut down digital communication or shut down Winlink in particular," Widin said, adding that ARRL recognizes Winlink's proven track record in emergency communication. His committee also will consider Winlink supporters' calls for the expansion of the ACDS segments spelled out in ¨97.221(b) of the amateur rules.

"This is not an easy task by any means," Widin allowed. "They're not making more bandwidth." He said this is especially a problem on 40 meters.

"We're well aware that Winlink is the de facto standard supporting emergency communications in many parts of the country, but we have to figure out how it can operate with other modes, so that everybody can communicate," Widin said, "without having one mode overrun any other mode." The committee will not address data encryption questions at this point, however.

In response to ARRL's 2013 petition to delete the so-called "symbol rate" limit and replace it with a maximum bandwidth for data emissions of 2.8 kHz below 29.7 MHz, the FCC proposed[2] to eliminate symbol rate (baud rate) limitations for data transmissions but declined to propose a bandwidth limitation.

At its July meeting, the ARRL Board of Directors called for ARRL's Washington Counsel to obtain FCC approval for several Part 97 rule changes. The Board asked for a rulemaking petition to remove the current 300 baud rate limitation; authorize all ACDS below 30 MHz, regardless of bandwidth, to operate only within the ACDS bands designated in ¨97.221(b); require digital stations operating with a bandwidth greater than 500 Hz to operate within the ACDS bands, whether or not automatically controlled, and limit the maximum bandwidth of digital signals below 29 MHz to 2.8 kHz.

ARRL-initiated mediation efforts for rival parties to reach consensus on all or some of the issues raised in the "symbol rate" proceeding ended a few days prior to the July Board meeting. While those discussion were useful, no consensus among parties was reached for FCC consideration. Widin said some positions may have been too divergent to find viable middle ground.

"We still want to change the symbol rate limitation into a bandwidth limitation, which makes a lot more sense in terms of current and future modes," Widin said. The panel also hopes to work with the WSJT-X Development Group to establish FT4 frequencies compatible with existing band plans.

Widin further suggested that his committee will have to look beyond the current landscape of HF digital modes into what might lie ahead.ÿ


[1] https://www.winlink.org/
[2] https://apps.fcc.gov/edocs_public/attachmatch/FCC-16-96A1.pdf

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