OGN-01-VLNA - Very Low Noise Amplifier designed for OGN Base Stations



TEST 1: "Blue" DVBT dongle vs Blue dongle+OGN-01-VLNA vs FlightAware dongle with SAW

Test conditions:
  • Test site with strong GSM/LTE signals
  • Distance to the two nearest BTS stations: 280m and 150m
  • Antenna: 5dBi Kathrein K7515641
  • Spectrograms generated by RPI based OGN test receiver
  • Dongle gain: +48dB

  • Three configurations tested:
    • Standard, "Blue" (RT820T2) DVBT dongle without external LNA
    • Blue dongle with OGN-01-VLNA connected
    • Modified FlightAware (orange) DVBT dongle with SAW filter placed between internal LNA and RT820T2
    • FlightAware (orange) dongle without SAW filter *NOT* tested (Rf.Input.Noise reported > 35dB, dongle completely overloaded)
GSM/LTE interference visible for blue dongle configuration.
Very good ISM sensitivity and resistance to the strong GSM/LTE signals for Blue dongle + OGN-01-VLNA setup.
Very strong GSM/LTE interference for modified FlightAware dongle.






TEST 2: ISM band receiving quality, ISM vs GSM/LTE signal strength levels and OGN-01-VLNA vs FlightAware dongle comparison

Test conditions:
  • Distance to the two nearest BTS stations: 920m and 1150m
  • Test site around 2 km from the Piotrkow (Poland) city
  • Trees around test site (additional attenuation for ISM/GSM/LTE signals)
  • Antenna: 8dBi Kathrein K736350, 2 meters above ground level
  • Gqrx software used as a spectrum analyzer

Reference setup. DVBT "Blue" dongle (RT820T2). +49.6dB dongle gain. No external LNA connected.
ISM band ISM vs GSM ISM vs LTE

OGN-01-VLNA connected. Total system gain around +77..78dB. Overall receiver noise figure around 0.4...0.5dB
Best SNR and receiving performance from all four setups. Clean spectrum, very high GSM/LTE attenuation.
ISM band ISM vs GSM ISM vs LTE




Standard "FlightAware" (orange) dongle. +49.6dB dongle gain, +19dB internal LNA gain. Total system gain around +69dB
Very high interference from GSM/LTE. Dongle gain reduced to +38dB (+57dB total system gain)
ISM band ISM vs GSM ISM vs LTE

Modified "FlightAware" (orange) dongle. SAW filter placed between internal LNA and RT820T2 tuner.
+49.6dB dongle gain, -2.6...-3dB SAW, +19dB internal LNA gain. Total gain around +66dB
Very good performance but SNR around 2dB worse than Blue Dongle + OGN-VLNA-01.
More sensitive to interference from GSM/LTE bands (see test 1).
ISM band ISM vs GSM ISM vs LTE