Re: First ROS test over QO-100 Sat #ros #sat #qrp

Siegfried Jackstien

hello graham

thanks for the repot of qrppp usable on the new sat

so ... you can grab a pluto without amp behind it ... and can do ros and have a good copy???

wow that is nice


today i was doing some bench testing of my new 10w amp

good for ssb .... maybe a bit to low power for datv

hope to be on the sat next weekend

greetz sigi dg9bfc

Am 09.04.2019 um 19:45 schrieb Graham:

First ROS test over QO-100  Sat #ros #sat #qrp

PA1SDB Condcted a QRP test over the  Sat link, using the  goonhilly  web-based sdr  for  RX
Of ROS-4  and Thor-4  data  modes  

Using  a  carrier level of  1.5 mW , to 95 cm Dish  for the  2.4 Ghz up link ,  , 
running  at   -22 / -23  dB s/n  [ 2.4 Khz b/w] average of the  tx time line  this  was at the  lower limit of the 
8 baud  ROS-4_HF mode , 

[ It was not  noted  till  post test, that  ROS-4  is  actually effective  8 baud  , 
compared to Thor 4  , being  4-baud  , ie effective  + 3 dB gain] 

With carrier level of 1.5 mW  , one error free  decode was achieved  ,  <crc-ok>  -22 
with partial decodes ,  at -23 dB ,  The tx  text  is not  recorded 

Using the  same  1.5 mW , similar text loss  occurred  using the  Thor-4  mode ,  though  , no indication is provided  as to  correct  decode ,  by  crc  check 

Noting that  Thor  at 4  baud , presented a  theoretical advantage of + 3 dB , due to  baud rate  being  50% 

Notes  on the  test . 

Unlike Opera ,  ROS remains the  same  for  all  bands ,  the  2  meter band is recommended to  separate  reporting as  best  as possible 

At -22 dB s/n  , an increase  of  +2  or +3 dB  power , ie to  3 mW would  of  produced 100% copy  in ros-4 ,  + 6 dB 12 mW  qso at  normal typing  speed  ,  ros-8  and  at  48 mW that would  enable ros-16 

More unstable equipment , Use of the  Highest  speed  is  recommended , 

Dial set Rx No QRG is reported, but, noting, being 2G , and  self  sync,  once a watering  hole is  'spotted , then  only that  dial usb setting  need  be used ,  as  all  traffic may co-occupy  the  same channel , at the  same QRP  power levels , probably best  demonstrated by the  27 MHz users , during  good  propagation,local and dx   all  activity  is  confined to  single channel , this from 2015 


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