[10m] Re: RM-11392

[WORKSNTV at aol.com]

Everyone:

Here is a response I got from  the author of RM-11392.  His email  is:
kramrellim at tx.rr.com


73'

Bob  Reynolds
WB3DYE
AAR3BA/T



In a message dated 12/27/2007  3:03:42 P.M. Eastern Standard Time, 
kramrellim at tx.rr.com  writes:
Bob,

I would be happy to comment.  Let me start by saying  that I am a 
digital enthusiast and have operated many digital modes  beginning 
with AMTOR, PACTOR I, and many of the sound card modes.  Back  in May 
of 2004 I submitted a petition to the FCC to allow image  
transmissions  occupying less than 500 Hz in the RTTY/Data portions  
80M though 10 meter bands.  I received a lot of feed back saying that  
not only image emissions, but all emissions in the RTTY/Data subbands  
should be limited to 500 Hz.  I started doing research in 2005  
looking at the history of our part 97 regulations and in particular 
the  regulations that affect the RTTY/Data subbands.  RM-11392 is the 
result  of that research.

The main goal of RM-11392 is the re-establishment of  the narrowband 
nature of the RTTY/Data subbands that has been lost.  We  have been 
guided by the following statement: The symbol rate must not exceed  
300 bauds, or for frequency-shift keying, the frequency shift between  
mark and space must not exceed 1 kHz.  This regulation was written  
prior to 1988 when owe had only CW and RTTY (FSK) emissions in the  
RTTY/Data subbands.  This set a bandwidth limit.  Early in 2000  there 
were new modes that used more than one sub carrier.  This was  fine, 
but these modes were not FSK and effectively there was no limit to  
the bandwidth these signals could occupy.  I feel that that since we  
are a shared frequency service, there needs to be a reasonable 
bandwidth  limit, especially on HF, where conditions get crowded and 
there is not much  bandwidth to begin with.  But what bandwidth is 
appropriate?

If you  take the statement: The symbol rate must not exceed 300 bauds, 
or for  frequency-shift keying, the frequency shift between mark and 
space must not  exceed 1 kHz and plug it into a standard bandwidth 
formula (one derived from  Carson's rule), you end up with a 1500Hz 
maximum bandwidth.  This I  feel is a reasonable bandwidth.  I knew 
that the PACTOR III folks and  some of the ALE folks would have a 
problem with this, because they routinely  use emissions that exceed 
1500 Hz in the RTTY/Data subbands.

In my  petition I go to great lengths to explain that Pactor III 
probably should  never have been used in the Ham bands because by its 
nature it is meant for  channelized operation, not shared frequency 
operation.  Please read the  first paragraph of the protocol description  at
http://www.scs-ptc.com/download/PACTOR-III-Protocol.pdf .  This is  
from SCS, the only makers of the Pactor III modem.  My petition does  
not elimlimate pactor III because there are two modes SL1 and SL2 
that  will fit in 1500 Hz and they happen to be the most robust.

Pactor III is  used mostly by stations engaged in automatic control 
and I have also asked  the FCC to move all automatically controlled 
stations, regardless of  bandwidth into the automatic control subbands 
within the RTTY/Data  subbands.

This is it in a nutshell, and if you or anyone else need  further 
detail, I would be happy to explain further.  My only agenda is  to 
close a loophole that has broken the narrowband nature of the  
RTTY/Data subbands.

I will forward an email sent to me by Peter  Martinez G3PLX ( inventor 
of AMTOR, PSK31, and FDMDV) in which he analyzes  my petition.  Feel 
free to distribute anything I send  you.

73,
Mark N5RFX  




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