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[Discuss-gnuradio] Setting tx_gain > 20 dB => no effect? (USRP2, XCVR245
Sven Oliver Kreis
[Discuss-gnuradio] Setting tx_gain > 20 dB => no effect? (USRP2, XCVR2450)
Mon, 21 Jun 2010 14:31:41 +0200
I am using an USRP2 with Gnu Radio Companion 3.3 and XCVR2450 as
daughterboard. I created a simple signal generator with grc.
Signal Source (Sample Rate 12.5M, Waveform: Sine, Frequency: 1,
Amplitude also 1, Offset 0) connected to USRP2 Sink (Interpolation 128,
I am also using one micaz node for RSSI Measurement. (using RssiToSerial
and a serial programming board) Distance between SDR and micaZ about
Taking 10000 RSSI Values per dB Step (stopping, changing Gain +1 in
USRP2 Sink, starting again with GRC ) I got the attached result.
(attached max RSSI value, can also attach average value, which looks
similar if requested)
I started at 0 dB Gain, so x= 1 <=> 0 dB GAIN at USRP2 Sink.
Noise floor is at -97 dBm (not in the plot). Starting USRP2 with Gain 0
gets it to about -62/-63 dBm at 0.5m distance.
Increasing gain increases RSSI value as expected. Not quite linear but I
At a gain of 20 the RSSI value reaches about -46 dbM. Increasing USRP2
Sink gain over 20 doesn't change anything. It seems to stay at about
Printing gain range results in 0 to 30 dB. Also mingain = 0 and maxgain
How to get more tx_gain? Something I do wrong there to make gain > 20
I can also attach the python code, if requested.
Thx in advance
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- [Discuss-gnuradio] Setting tx_gain > 20 dB => no effect? (USRP2, XCVR2450),
Sven Oliver Kreis <=