This is merely a historical archive of years 2008-2021, before the migration to mailman3.
A maintained and still updated list archive can be found at https://lists.osmocom.org/hyperkitty/list/OpenBSC@lists.osmocom.org/.
Gullik Webjorn gullik.webjorn at corevalue.seTue 15-jan-2019 LimeSDR transmit check. Fired up old HP 8614A signal generator at 1880 Mhz, and let it stabilize for 1 hour. Level measurement after adjusting ALC, 0dBm = -0.4 dBm as checked with spectrum analyzer Checked level with HP L423A probe. Check of LimeSDR mini output. Output as seen on spectrum analyzer -1.0 dBm. This correlates with LMS7002 datasheet with a possible 1 dB loss between chip and analyzer, including SMA-BNC coax adapter, 2 m foam insulated RG58 size cable, BNC - N connector. So, for practical purposes the LimeSDR mini provides 0 dBm ( +/- 1.4 dBm ) LimeSDR receive check. Receive antenna rigged with a 1/10 dB splitter, -10 dB port connected to spectrum analyzer, -1 dB port to LimeSDR. Connect single Nokia Handset, and make a call from osmobsc to fixed phone, so that only one mobile is using TCH. Move phone to get different uplink levels and correlate these to spectrum analyzer. Since carrier is TDMA, use peak hold on analyzer. Active subscriber connections: conn ID=31, MSC=0, hodec2_fail=0, mgw_ep=rtpbridge/1 at mgw BTS 1, TRX 0, Timeslot 1, Lchan 0: Type TCH_F Connection: 1, State: ESTABLISHED BS Power: 10 dBm, MS Power: 10 dBm Channel Mode / Codec: SPEECH_V1 No Subscriber Bound IP: 192.168.1.75 Port 16384 RTP_TYPE2=0 CONN_ID=0 Conn. IP: 192.168.1.70 Port 4110 RTP_TYPE=3 SPEECH_MODE=0x00 Measurement Report: Flags: MS Timing Offset: 0 L1 MS Power: 10 dBm, Timing Advance: 4 RXL-FULL-dl: -51 dBm, RXL-SUB-dl: -51 dBm RXQ-FULL-dl: 0, RXQ-SUB-dl: 0 RXL-FULL-ul: -54 dBm, RXL-SUB-ul: -54 dBm RXQ-FULL-ul: 0, RXQ-SUB-ul: 0 Level on uplink -54 dBm, indicated on spectrum analyzer -53 (-63) dBm. OsmoBSC# show conn Active subscriber connections: conn ID=31, MSC=0, hodec2_fail=0, mgw_ep=rtpbridge/1 at mgw BTS 1, TRX 0, Timeslot 1, Lchan 0: Type TCH_F Connection: 1, State: ESTABLISHED BS Power: 10 dBm, MS Power: 10 dBm Channel Mode / Codec: SPEECH_V1 No Subscriber Bound IP: 192.168.1.75 Port 16384 RTP_TYPE2=0 CONN_ID=0 Conn. IP: 192.168.1.70 Port 4110 RTP_TYPE=3 SPEECH_MODE=0x00 Measurement Report: Flags: MS Timing Offset: 0 L1 MS Power: 10 dBm, Timing Advance: 4 RXL-FULL-dl: -69 dBm, RXL-SUB-dl: -69 dBm RXQ-FULL-dl: 0, RXQ-SUB-dl: 0 RXL-FULL-ul: -59 dBm, RXL-SUB-ul: -59 dBm RXQ-FULL-ul: 0, RXQ-SUB-ul: 0 Mobile moved to another location within the lab. Level on uplink -59 dBm, indicated on spectrum analyzer -60 (-70) dBm. Conclusion: For such a simple low cost SDR, the accuracy seems within a couple of dB. Instruments used were are not "professional grade", at least not w.r. 2019, but I estimate I can measure within +/- 2 dB or so with this crude config. Power output is 10 times lower than I expected, I was probably mislead by some review on the web, and had to go down to the actual scematic and datasheet to understand that the expected level should be around 0 dBm. (thanks for pointing this out, Harald) For practical use outside a lab output is far too low. My plan is to add a small simple booster to bring level up to +15 which would allow me to cover my 2 acre lot without breaking any rules. Else, I am impressed, good value for a low price tag. I had expected far worse than indicated accuracy. Best Regards, Gullik