VARA -SAT- Dynamic net facility #VARA
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
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.
This version, at our request, integrates the Calibration function, very useful via satellite and for those without GPS.
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.
dg0opk Lists equipment used
[SDR console , has beacon AFC-Lock , specially designed for the Sat
used the band edge CW beacon to lock qrg]
Peak Data Rate: 3500bps
TCXO LNB with software drift correction on QO-100 BEACON (SDR Console), ADALM PLUTO (TCXO MOD) in FULLDUPLEXMODE, SDR Console V3.0.11 ,Virtual Audio to Vara Modem, RX/TX Switch ... VOX Controlled by SDR Console
Reports , sending 70 Kb in 4 min 18 sec , via :-
IS0GRB Winlink Server on QO-100 (Dial 10489635.0 USB)Bernd posts
''This morning I made a speed measurement with VARA SAT with winlink express via OSCAR-100.
I sent a file with app. 70 kbytes size from Zirndorf, Germany to IS0GRB island Sardinia ( Italy ).
I have a FTDX3000, a signalink sound card and the DL2BZ transverter driven by Leo Bodnars great GPSDO.
The file was sent in a time of 4min18s.