VARA -SAT- Dynamic net facility #VARA

Graham
 
Edited

VARA  -SAT-  Dynamic net facility 

This puts  portable operation  , from  low power non gps locked systems on the  table 

Latest version , contains an interrogator , which,  produces a response  from the  wanted  station , 
indicating the  level of  frequency   'off net'  [ similar to  IFF  or Secondary radar ] 

This allows  a connecting  station to  'find'  the  wanted  gateway , and to  then  commence  transmission
[ solving the  age old problem with  duplex sat work of  netting ]

The  vara-sat version , now has  undergone  considerable  testing  and  modification over the  geo-sat link, and now  provides extended  latency  , with  enhanced  AFC 

PA1SDB , Conducted  low power test  and reports  data  transfer with   70 mW to  120 cm dish  ,  the  Modem  reached  level  3  , the  maximum  un-registered speed  173 baud  , problems  experienced , where  trying to  reduce the  power, to a  lower level ! , 

Follow the  progress  , being  reported  on the  Amsat-DL  web-site 

https://forum.amsat-dl.org/index.php?thread/2829-is0grb-winlink-server-on-qo-100-dial-10489635-0-usb/&pageNo=3


Roberto IS0GRB Testing the  system with  his  RMS gateway , posts  :-


This evening Jose EA5HVK has released the version 3.0.5 of the VARA SAT modem.

 

https://rosmodem.wordpress.com/2011/01/10/ros-2

 

This version, at our request, integrates the Calibration function, very useful via satellite and for those without GPS.


In the Calibration menu the client transmits a signal to the server, normally controlled by GPS, or to another client controlled or not by GPS, which reply with its signal and the shift detected by the client who launched the test.

 

It is therefore possible to know your own AFC value detected by the correspondent and center the VFO, so as to reset the AFC to 0 (zero) without the aid of a WebSDR and therefore of internet connection.

73

Roberto IS0GRB











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