[RTTY] Will You Let FCC Kill PACTOR3?

Kok Chen chen at mac.com
Thu Dec 27 13:23:38 EST 2007


On Dec 27, 2007, at 8:58 AM, WS7I wrote:
>> RM-11392

For details, go to

http://www.southgatearc.org/news/december2007/bandwidth_band_plan.htm

where you can find links to the pdfs of the original RM.

The following are my impressions.

RM-11392 proposes that the FCC go back to use the old definition of  
allowable bandwidths for 12m through 80m ham bands so that RTTY and  
Data modes are limited to a bandwidth of 1500 Hz.

1500 Hz is plenty of bandwidth.  Among the digital modes in use  
today, RTTY uses about 215 Hz, MFSK16 uses 316 Hz.  MT63 and Olivia  
uses up to 1000 Hz.  All of which would easily fit within the  
proposed limit of 1500 Hz.  There is a 2000 Hz variant of Olivia  
which I am not sure is often used.

The only currently used digital mode that occupies more than 1500 kHz  
is the higher data rate steps of Pactor III (Pactor III keeps  
increasing bandwidths if the path allows it to, up to about 2200 Hz).

The RM also asks for clarification of what an automatically  
controlled station is, and limiting them to above 14.095 MHz on 20m,  
for example.

RM-11392 pretty much attempts to keep Pactor III in particular, and  
automatic stations in general, from interfering with keyboard digital  
modes.  Just MHO, of course.

73
Chen, W7AY



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