Re: VARA vs. Pactor-III Speed Comparison Plots


Thank's for the  info Tony

Ah, clash of times,  the  new version has some  re-working  of the  lower speed's ,  a lot of  test data  has only been  made  available, since the  modem entered service , we could only  test over the  1000 mile  path  UK<>EA . The  latest HF version is  now frozen , good  reports of  maritime  mobile  EU<>VE  exchanges on 7 MHz , are posted in the  google 'vara'  group.

The power consumption   ofdm / mmfsk  is relevant, in the  sense , that  it affects the system  s/n moving  from  25  watts  average power ,  vara mode designed tx level , to  single carrier  , 100%  duty ,  raises the  level by  6 dB , but at  a disproportionately lower  data rate .

Work and testing continues for the  high speed  'FM'  variants ,  both  standard  2 meter FM  and  9600 baud replacement  modem  , topping out at  15K bps 

Take up on these versions  has not been  too  high ,  possibly as there point to point only , suited for trunking links , where as the  existing systems ,  1200/9600 baud are capable of  supporting  packet ax25l as well, due to frequency tolerance ,  there  only  suited to FM  transmission, where  the  tone  frequencies  are  protected  by the  modulation type. 

Pactor 4 , yes , that remains to  be  tested , if any one  can undertake  such a  test ,  the  results would be  quite interesting ..


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