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

[Dave AA6YQ]

>>>AA6YQ comments below

From: digitalradio at yahoogroups.com [mailto:digitalradio at yahoogroups.com] On Behalf Of Rick Muething
Sent: Sunday, December 08, 2013 9:31 AM
To: digitalradio at yahoogroups.com; rtty at contesting.com; DX-IS at yahoogroups.com; MMTTY at yahoogroups.com; multipsk at yahoogroups.com
Subject: RE: [digitalradio] Why (and How) You Should Urge the FCC to Reject the ARRL's Symbol Rate Petition

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. 

>>>I disagree. The current 300 baud HF symbol rate limit restricts transfer rate, and thus makes modes greater than 2200 hertz of
little value to message passing networks. The ARRL's proposal both removes the 300 baud HF symbol rate limit, and sets a maximum HF
bandwidth of 2800 hertz. If the ARRL petition were accepted, operators could deploy 2800 hertz digital modes with higher transfer
rates that what Pactor 3 provides (in 2200 hertz). Switching to such modes would be attractive to message passing networks.
 
 
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.  

>>>That's incorrect, Rick. At present, the "speed limit" within these HF sub-bands is set by the 300 baud symbol rate limit. The
ARRL's petition, if accepted, would eliminate this limit, replacing it with a 2800 hertz limit on bandwidth. One or more 2800 hertz
modes with transfer rates significantly faster than that of Pactor 3 would soon be in use by message passing networks.

  
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. 

>>>The statement above is accurate: WinLink's "Rules and Guidelines" web page states

 "On HF Pactor, the radio users of the Winlink 2000 system initiating a contact are present as control operators, and therefore,
WinLink 2000 operations do not fall within the category of "automatic control" per U.S. FCC Part 97.221."

<http://www.winlink.org/guidelines>


 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. 

>>>97.3(13) defines "Control Operator" as "An amateur operator designated by the licensee of a station to be responsible for the
transmissions from that station to assure compliance with the FCC Rules."

>>>The "Rules and Guidelines" web page's claim that the "radio users of the Winlink 2000 system initiating a contact are present as
control operators" is nonsense. Such operators have no ability to " manipulate the operating adjustments in the station through a
control link to achieve compliance with the FCC Rules", as is required by 97.3(38). 

>>>In the absence of a remote control link conformant with 97.3(38), Winlink servers are automatic stations, as defined by 97.3(6);
if using a mode wider than 500 hertz, WinLink servers are subject to 97.221. 


 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). 

>>>Excellent! If that's the case, then you should join me in urging the FCC to reject the ARRL's petition in favor of an improved
petition that requires automatic stations to incorporate busy frequency detectors. This would reduce the incidence of interference
with ongoing QSOs -- the opposite of what the current ARRL petition would do if adopted.

 
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.  

>>>As of last week, the "RMS Channels" web page you cite listed the following Pactor III stations with center frequencies outside
the 97.221 sub-bands: WG3G on 3569.0, N4MEH on 3580.0, W5SEG on 7067.5, K0SI on 7105.9, KC4TVO on 10139.5, and K9BBS-10 on 14112.5.


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. 

>>>Neither reciting facts nor projecting the consequences of proposed actions constitutes "bashing".

>>>I support the elimination of the 300 baud limit on HF, and I support the permission of HF digital modes wider than 2200 hertz --
but in a manner that does not increase interference to current users. Allowing automatic stations to employ 2800 hertz modes without
requiring them to incorporate busy frequency detectors will increase the interference to ongoing QSOs - the opposite of what is
required.

>>>If Winlink is now incorporating busy frequency detectors in its servers as you claim above, then you should support rejection of
the current ARRL petition in favor of a petition that also requires automatic stations to incorporate busy frequency detectors. This
would reduce rather than increase interference to ongoing QSOs by incentivizing automatic stations to incorporate busy frequency
detectors; it would eliminate much of the opposition to the current ARRL proposal.

       73,

                    Dave, AA6YQ