QST de W1AW
ARRL Bulletin 37 ARLB037
>From ARRL Headquarters
Newington CT October 12, 2016
To all radio amateurs
SB QST ARL ARLB037
ARLB037 Current Rules Holding Hams Back from Adopting
State-of-the-Art Technology, ARRL Says
In comments filed on October 12 with the FCC, ARRL reiterated its
case that the FCC should impose a 2.8 kHz limit on symbol rate for
digital modes, arguing that its approach is both balanced and
necessary. ARRL had asked the FCC to change the Part 97 rules to
delete the symbol rate limits in Part 97.307(f) and replace them
with a maximum bandwidth for data emissions of 2.8 kHz on amateur
frequencies below 29.7 MHz. In a July Notice of Proposed Rule Making
(NPRM) in WT Docket 16-239, the FCC proposed to eliminate the
current baud rate limitations for data emissions, consistent with
ARRL's Petition, but it declined to propose a bandwidth limitation
for data emissions in the MF and HF bands to replace the baud rate
ARRL's comments can be found on in PDF format on the web at,
ARRL told the FCC in its comments that the current HF symbol rate
'speed limit' reflects 1980s technology and has no place in an
experimental radio service in which modern protocols could be
efficiently deployed in crowded RTTY/data subbands.
'The symbol rate limit was created in order to maximize the
efficient use and reuse of that crowded, shared spectrum, but the
assumptions made at the time are no longer valid,' ARRL said, 'and
the rules now prohibit radio amateurs from utilizing
state-of-the-art technology, thus precluding or substantially
inhibiting any meaningful contribution to the advancement of the
radio art in this area.' ARRL said earlier assumptions are no longer
valid mainly because there is no correlation between the data rate
and the occupied bandwidth in the rules now.
The League said present rules in the HF data subbands promote
inefficiency, allowing data transmissions of unlimited bandwidth as
long as the symbol rate is sufficiently low, and it stressed that
there must be some limit on occupied bandwidth for HF data
'Eliminating the symbol rate limitations for data emissions and
substituting a maximum authorized bandwidth would permit the
utilization of all HF data transmission protocols presently legal in
the Amateur Radio Service, as well as state-of-the-art protocols
that fall within the authorized bandwidth,' the League said.
ARRL said that it could be 'fairly debated' whether or not 2.8 kHz
is the proper maximum bandwidth for data emissions. 'Greater
bandwidth for data emissions would permit a wider array of data
emissions now and in the future,' the League said in its comments.
'However, even 2.8 kHz could arguably permit usurpation of the
subbands to the detriment of CW and other narrow-bandwidth
emissions. ARRL views the 2.8 kHz maximum bandwidth proposal for
data emissions at HF to be a necessary component of the FCC's
proposal, and it fairly balances the objectives of facilitating use
of new and future data emissions and protecting against usurpation
of the band by a few data stations.
ARRL said it would be impossible to reduce the permitted maximum
bandwidth for data emissions at HF much below 2.8 kHz without
prohibiting data modes that are now legal. 'At the same time, it
would not be desirable to have a few data stations using large
swaths of spectrum to the detriment of other modes,' the League
The deadline to file reply comments in the proceeding - ie, comments
on comments already filed - is November 10.
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