Re: VARA vs. Pactor-III Speed Comparison Plots


Hi Tony , More than 60 hour’s that was quite a feat !


There are some interesting points linked to the development of the  vara modem


The initial version, did deploy a change of protocol for the  lower speed  ranges , but,  with development , the  data  rates / s/n  of the  ofdm  modem ,  exceeded the  conventional  mfsk  rate/s/n.


Actually better  than 2fsk conventional rtty  , hence the  modem remains ‘single protocol’ ofdm  with  ‘low on air rate’ at all speeds  , with advantages of  noise rejection, selective fade , multiple path  over narrow b/w mfsk


Q:  When amtor  changes to  mfsk,  do you  note a higher level  of  power consumed ,ie , the supply current to the  Tx  increases , if so ,  what  change ?


Pactor  4


Q: Is it possible to run tests of the  vara  modem  against the  Pactor 4  modem, can anyone perform such a test ?


There  is a  interesting  ‘clash of  concept’ , with the  use of  high speed  serial  carriers , and the  low on air rate  multiple  carriers  of the  vara  ofdm  modem , to date , this  remains to be  explored …




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