[OKDXA] ARRL Files Comments Against Seriously Flawed HF Rules Petition

[Jeff Martin]

ARRL Files Comments Against “Seriously Flawed” HF Rules Petition
08/02/2023
ARRL  The National Association for Amateur Radio®, as part of its 
mission to protect Amateur Radio, has filed comments against a proposal 
that would introduce high-power digital communications to the shortwave 
spectrum that in many instances is immediately adjacent to the Amateur 
HF bands.

The “Shortwave Modernization Coalition” (SMC), which represents certain 
high-frequency stock trading interests, filed the petition with the 
Federal Communications Commission (FCC). (Previous coverage can be found 
on ARRL News.) ARRL responded on behalf of its members and the 760,000 
licensees of the Amateur Radio Service in the US.

The ARRL Laboratory performed a detailed technical analysis over several 
months to determine if the proposed rules would affect operations on the 
bands allocated to Radio Amateurs that are inter-mixed with the Part 90 
bands in the spectrum in question.

ARRL’s analysis determined that, if the proposed rules are adopted, the 
new operations inevitably will cause significant harmful interference to 
many users of adjacent and nearby spectrum, including Amateur Radio 
licensees. Ed Hare, W1RFI, a 37-year veteran of the ARRL Lab and 
internationally recognized expert on radio frequency interference, was 
the principal investigator on the study. Hare concluded the petition 
should not be granted. “This petition seeks to put 50 kHz wide, 
20,000-watt signals immediately next to seven different amateur bands 
with weaker protections against interference than required in other 
services,” said Hare.

In its formal opposition, ARRL stated, “That destructive interference 
would result if operations commenced using anything close to the 
proposed maximum levels.”

ARRL’s filed comments highlight flawed analysis and incomplete data 
submitted by the petitioners. It noted the petitioners “…significantly 
understate the harmful interference that is not just likely, but 
certain, if the rules proposed by SMC are adopted as proposed. It is 
noteworthy that SMC’s proposed rules would provide less protection than 
the much-lower power amateur radio transmitters are required to provide 
Part 90 receivers.” ARRL’s opposition also noted that there was no 
reported tests conducted with Amateur or other affected stations, but 
referenced a spectrum capture in the Comments filed with the Dayton 
Group that showed actual interference into the Amateur 20-meter band 
from one of the High Frequency Trading experimental stations.

Part 90 HF rules currently authorize a maximum signal bandwidth equal to 
a voice communications channel, at up to 1000 W peak envelope power 
(PEP). The petition seeks multiplication of signal width, greater 
transmitted power, and weaker rules that protect users of adjacent 
spectrum. ARRL’s comments expose the likely fallout:

“Incredibly, notwithstanding the significant increase in potential 
interference that would result from using digital schemes with 50 kHz 
bandwidths and 20,000 watts of power, SMC also proposes to substantially 
lessen the protections required to protect adjacent and neighboring 
licensees. SMC proposes [out-of-band emissions] limits that offer less 
protection than the existing Part 90 limits and would actually permit no 
attenuation (0 dB) at the edge of adjacent allocations, many of which 
are bands allocated to and heavily used in the Amateur Radio Service. 
Consistent with lessening protections while increasing the potential for 
harmful interference, SMC also proposes a lower limit for spurious 
emissions. SMC would reduce the existing protection of -73 dB for the 
applicable 1000-watt power limit to just -50 dB protection for their 
proposed 20,000-watt limit. Due to the much wider 50 kHz proposed 
bandwidth, the resulting interference would penetrate deep into the 
adjacent Amateur bands.”

The proposal has been assigned FCC Docket No. RM-11953. While the period 
for commenting on the petition has now closed, replies to comments in 
the record may now be submitted.

Hundreds of licensed Radio Amateurs filed comments in the Docket, 
expressing overwhelming opposition to the proposal. Those interested may 
read ARRL’s full comments and the results of the technical analysis, 
which are included in the filing. “If granted as written, this would be 
devastating to Amateur operation for many tens of kHz into our bands,” 
said Hare.

ARRL will continue to advocate for its members and the Amateur Radio 
Service in this proceeding.