Hello,
Could you please help me (or point me to the appropriate tools) to reduce the "noise" on the board... What is the best tool(s) to (re)calibrate the board.
Serial #: 13d7b32e83118203e3e6db0b04de23bf
VCTCXO DAC calibration: 0x91b1
FPGA size: 115 KLE
FPGA loaded: yes
USB bus: 4
USB address: 2
USB speed: SuperSpeed
Backend: libusb
Instance: 0
bladeRF> version
bladeRF-cli version: 1.1.2-git-0295340
libbladeRF version: 1.2.1-git-0295340
Firmware version: 1.8.0
FPGA version: 0.1.2
I run some tests using yatebts and the connection was very unstable...
===================================
mbts noise
noise RSSI is -13 dB wrt full scale
MS RSSI target is -50 dB wrt full scale
mbts rxgain
current RX gain is 0 dB
===================================
-13db is the minimum reachable on the board.
I tried to calibrate the board with "kalibrate-bladeRF", and it looks even worse.
./src/kal -s GSM850 -m4
Actual filter bandwidth = 1500 kHz
rxvga1 = 20 dB
rxvga2 = 30 dB
kal: Scanning for GSM-850 base stations.
GSM-850:
chan: 128 (869.2MHz - 1.362kHz) power: 35627.82
chan: 129 (869.4MHz - 1.349kHz) power: 37119.38
chan: 130 (869.6MHz - 1.382kHz) power: 37840.33
./src/kal -v -c 128
Found lowest offset of 264.594208Hz at 869.200000MHz (0.304411 ppm) using DAC trim 0x8fff
=====
Thank you,
BladeRF x115 / YateBTS / Noise
-
- Posts: 29
- Joined: Mon Mar 02, 2015 2:02 pm
Re: BladeRF x115 / YateBTS / Noise
Hello,
when you execute mbts noise and the result is:
noise RSSI is -13 dB wrt full scale
MS RSSI target is -50 dB wrt full scale
in my own experience it is because of the one of following things:
RX antenna not matched (not taylored for the band in use)
TX antenna too colse from the RXantenna
mbts rxgain set >0
I got the same your results in these cases,
but if you tray with a dummy load (50 ohm) on both RX and TX ports you get around -46 dB of noise RSSI (tray to set mbts rxgain =0)
for a well matched antenna I got around -30 dB of noise
when you execute mbts noise and the result is:
noise RSSI is -13 dB wrt full scale
MS RSSI target is -50 dB wrt full scale
in my own experience it is because of the one of following things:
RX antenna not matched (not taylored for the band in use)
TX antenna too colse from the RXantenna
mbts rxgain set >0
I got the same your results in these cases,
but if you tray with a dummy load (50 ohm) on both RX and TX ports you get around -46 dB of noise RSSI (tray to set mbts rxgain =0)
for a well matched antenna I got around -30 dB of noise
-
- Posts: 1
- Joined: Mon Oct 19, 2020 7:51 am
Re: BladeRF x115 / YateBTS / Noise
Thanks for your post.
First of all it helped me to determine that a noise of -35 dB is not unusual on a bladeRF (although I have the x40 not the x115).
However, I am extremely puzzled by the stuff below bold for the main points.
I tried to run the noise command with rxgain as 75 and then after changing rxgain to 0.
What is puzzling is that the noise seems basically the same (-35 vs -34 dB).
Any ideas/suggestions?
Additionally, seems way higher than the recommended value by Yate ("Normal UL noise level is -64 or lower").
Indeed, I mange to have reasonable voice and SMS but horrible if any GPRS...
Many thanks in advance.
-----------------------------------------------------------------------------
mbts rawconfig rxgain 75
defined new config rxgain as "75"
mbts noise
noise RSSI is -35 dB wrt full scale
NOTE: Excessive UL noise will degrade performance. Normal UL noise level is -64 or lower.
MS GSM RSSI target is -50 dB wrt full scale
NOTE: GSM UL RSSI margin -15 too low for this noise level. Should raise GSM.Radio.RSSITarget to -27 dB or higher.
MS GPRS RSSI target is -25 dB wrt full scale
NOTE: GPRS UL RSSI margin 10 too low for this noise level. Should raise GPRS.MS.Power.RSSITarget to -21 dB or higher.
mbts rawconfig rxgain 0
rxgain changed from "75" to "0"
mbts noise
noise RSSI is -34 dB wrt full scale
NOTE: Excessive UL noise will degrade performance. Normal UL noise level is -64 or lower.
MS GSM RSSI target is -50 dB wrt full scale
NOTE: GSM UL RSSI margin -16 too low for this noise level. Should raise GSM.Radio.RSSITarget to -26 dB or higher.
MS GPRS RSSI target is -25 dB wrt full scale
NOTE: GPRS UL RSSI margin 9 too low for this noise level. Should raise GPRS.MS.Power.RSSITarget to -20 dB or higher.
First of all it helped me to determine that a noise of -35 dB is not unusual on a bladeRF (although I have the x40 not the x115).
However, I am extremely puzzled by the stuff below bold for the main points.
I tried to run the noise command with rxgain as 75 and then after changing rxgain to 0.
What is puzzling is that the noise seems basically the same (-35 vs -34 dB).
Any ideas/suggestions?
Additionally, seems way higher than the recommended value by Yate ("Normal UL noise level is -64 or lower").
Indeed, I mange to have reasonable voice and SMS but horrible if any GPRS...
Many thanks in advance.
-----------------------------------------------------------------------------
mbts rawconfig rxgain 75
defined new config rxgain as "75"
mbts noise
noise RSSI is -35 dB wrt full scale
NOTE: Excessive UL noise will degrade performance. Normal UL noise level is -64 or lower.
MS GSM RSSI target is -50 dB wrt full scale
NOTE: GSM UL RSSI margin -15 too low for this noise level. Should raise GSM.Radio.RSSITarget to -27 dB or higher.
MS GPRS RSSI target is -25 dB wrt full scale
NOTE: GPRS UL RSSI margin 10 too low for this noise level. Should raise GPRS.MS.Power.RSSITarget to -21 dB or higher.
mbts rawconfig rxgain 0
rxgain changed from "75" to "0"
mbts noise
noise RSSI is -34 dB wrt full scale
NOTE: Excessive UL noise will degrade performance. Normal UL noise level is -64 or lower.
MS GSM RSSI target is -50 dB wrt full scale
NOTE: GSM UL RSSI margin -16 too low for this noise level. Should raise GSM.Radio.RSSITarget to -26 dB or higher.
MS GPRS RSSI target is -25 dB wrt full scale
NOTE: GPRS UL RSSI margin 9 too low for this noise level. Should raise GPRS.MS.Power.RSSITarget to -20 dB or higher.