[RTTY] [digitalradio] Why (and How) You Should Urge the FCC to Reject the ARRL's Symbol Rate Petition

[Rick Muething]

Dave,

 

Each is entitled to his opinion and you can file yours with a proper
response to the FCC proposed rule change RM-11708.  A comment response to a
proposed rule change doesn't have to be particularly accurate or logical
.those reviewing the comments however actually for the most part really do
understand the technology and the proposed rule changes.  

 

However when you use a forum like this one to encourage others to comment it
should be your personal responsibility to try and get the facts correct and
present them in a honest and straightforward way. 

 

Your comment:  "If accepted, digital modes as wide as 2800 hertz would
become legal for use by US hams on HF bands. Pactor 3, which is legal under
the current symbol rate limit, is 2200 hertz wide."

 

Is misleading. There is currently NO specified bandwidth limit to digital
modes.  The symbol rate rule does NOT (as was probably intended in 1980)
restrict bandwidth.   There are many digital modes at 2 KHz or above.  The
proposal RM-11708 simply specifies a practical and easily measured
restriction of bandwidth. The proposed limit is no more than SSB voice and
considerably less than AM.  It is also a practical limit compatible with
most SSB transceivers.  If you don't like 2800Hz bandwidth limit propose
another and suggest it also be applied to SSB voice, AM, MT63, ALE etc.
There are numerous modern and efficient HF Modem protocols that could be
adapted for Ham radio use (Mil Std 188, STANAG etc.)if the symbol rate rule
were not in effect. 

 

 

Your comment: "While US-based automatic stations using digital modes wider
than 500 hertz are restricted to specified sub-bands (e.g. 10,140 -

10,150, 14,095 - 14,099, 14,101-14,112, 21,090 - 21,100, 24,925 - 24930),
these frequencies are shared with QSOs between live operators."  

 

Is technically correct.  But in fact ALL ham radio frequencies are shared by
everyone (no one user or mode has exclusive rights).   The fact that
automatic and wideband digital modes are limited to relatively small band
segments (15 Khz or less below 28 MHz) in the US insures those operating
OUTSIDE  those narrow segments should be free from any such interference.
The proposed rule change does NOT change these auto forwarding sub bands.
Other countries may have different rules and the proposed RM-11708 has no
jurisdiction on those countries. 

  

Your comment: "Furthermore, the WinLink network now claims that its
automatic stations are actually under the control of the remote

stations that invoke them, and are therefore no longer restricted to these
sub-bands."

 

Is misleading.  All HF Winlink HF stations (all supported protocols) are and
always have been passive stations responding only to a call to their
specific call sign. They never use beaconing or sounding.  This has also
been the practice of most HF BBS stations since the 1980's.   The current
law clearly defines what is restricted to the sub bands and no changes to
this are proposed in  RM-11708.  Winlink developed an effective busy
detector (all modes) and Winlink HF stations routinely use this technology
to prevent responding to a call when a frequency appears busy (When the
calling station fails to listen first or there is a "hidden" transmitter). 

 

Your comment: "This network (Winlink) now advertises US-based automatic
stations running Pactor 3 outside the automatic sub-bands - automatic
stations that could be upgraded to 2800 hertz modes if the ARRL Petition is
accepted."

 

Is simply incorrect.  Winlink publishes the frequencies and protocols used
publically for all stations (US and others) on its web page
http://www.winlink.org/RMSChannels  .  The Winlink software specifically
monitors and limits operation to correct auto forwarding bands for US call
signs. Any violator (US or otherwise) of amateur rules is notified and if
not immediately corrected is blocked from operating (as a USER OR SYSOP )
from the Winlink system.  

 

Rather than continually bashing the all-volunteer Winlink system or the ARRL
for trying to simplify the rules and advance the state of the art why not
look at the proposed rule change as written and look at what it is trying to
do:

1)      Define a practical and easily measured mechanism (bandwidth) to
regulate digital modes. The symbol rate rule doesn't limit bandwidth as is
proven by the large number of OFDM modes available and in common use.  The
proposed bandwidth limit is compatible with virtually all Ham SSB
transceivers and consistent with the vast majority of world-wide amateur
rules. 

2)      Allow and encourage digital mode development and experimentation.
This has been proven (e.g. the CODEC2 project which can provide noise free
digital voice in HALF the bandwidth of SSB voice and Pactor 4 which has the
highest digital mode efficiency bits/sec/Hz).  The existing symbol rate rule
is a significant factor why the US has no viable modern Ham HF modem
manufactures and lags the rest of the world in amateur digital protocol
development. 

 

Respectfully, 

 

Rick Muething, KN6KB