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Petition for Rule Making Calls for “Amateur Digital Mode Transparency”


The FCC is accepting comments on a Petition for Rule Making (RM-11831) seeking to amend FCC Part 97 rules that require all ham radio digital transmissions to use techniques “whose technical characteristics have been documented publicly.” The Petition, filed by Ron Kolarik, K0IDT, of Lincoln, Nebraska, expresses concerns that some currently used digital modes are not readily and freely able to be decoded, and it asks the FCC to require all digital codes to use protocols that “can be monitored in [their] entirety by third parties with freely available, open-source software,” per §97.113(a)(4).

Kolarik said his petition also aims to reduce levels of amateur-to-amateur interference from Automated Controlled Digital Stations (ACDS) on HF operating under §97.221(c)(2). Kolarik wants the FCC to delete §97.221(c), which permits automatic control of digital emissions provided the station “is responding to interrogation by a station under local or remote control, and [n]o transmission from the automatically controlled station occupies a bandwidth of more than 500 Hz.” The petition does not call for eliminating ACDS, however. Under current rules, ACDS are allowed in specific sub-bands.

In his Petition, Kolarik maintains that interference from ACDS continues to be “a major problem on the amateur bands.” He suggested that an absence of formal complaints may be due to the fact that such stations are “difficult to identify.”

The Petition also proposes to amend §97.309(a)(4) to ease monitoring of certain digital transmissions. “Without open, over-the-air interception capability for all transmissions in the Amateur Radio spectrum, there is no way to determine if there is commercial or other prohibited, inappropriate content in ongoing communications…” Kolarik’s Petition asserts. He said problems arise when “protocols and devices used in commercial, government, and marine services are used in the Amateur Service with no adequate means to fully decode transmissions,” thwarting any efforts at self-policing of such transmissions. He said simplifying the language “would remove ambiguity about what constitutes ‘publicly documented technical characteristics’ by requiring any protocol to be freely decodable,” and lead to “amateur digital mode transparency, present and future.”

Kolarik contended in his petition that FCC action stemming from ARRL’s 2013 “symbol rate” Petition for Rule Making could increase congestion (i.e., interference) problems. In July 2016, the FCC in WT Docket 16-239 proposed to revise the Part 97 rules to eliminate current baud rate limitations for data emissions, consistent with ARRL’s Petition, but declined to propose a bandwidth limitation for MF and HF digital to replace current baud rate limitations. ARRL had asked the FCC to delete the symbol rate limits in §97.307(f) and replace them with a maximum bandwidth for data emissions of 2.8 kHz on amateur frequencies below 29.7 MHz. 



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