The PPM setting here refers to frequency uncertainty with a default of 120
, which is fine to evaluate the frequency correction.
Once you’ve got some correction value, use --correction
instead and eventually reduce PPM uncertainty down to 10
or something.
Grab & build LTE-Cell-Scanner
LNA is hardcoded at 40
and you can only lower VGA, here down to 20
.
apt install libitpp-dev liblapack-dev fftw-dev librtlsdr-dev # sfftw-dev #git clone git://github.com/Evrytania/LTE-Cell-Scanner.git #git clone https://github.com/rxseger/LTE-Cell-Scanner.git git clone https://github.com/JiaoXianjun/LTE-Cell-Scanner.git cd LTE-Cell-Scanner/ mkdir build/ cd build/ cmake ../ -DUSE_HACKRF=1 echo $MAKEFLAGS make
Watch GQRX and find some LTE channels up there, which can be differenciated from 3G/UMTS pretty easily (see links in Resources section). Then look at a precise range and target center frequency.
best w/o ppm range (default is 120) e.g.
src/CellSearch --gain=40 --freq-start 816e6 --freq-end 816e6
then calculate the PPM out of the correction factor
>>> 1e6 * (1 - 1.0000098318703387612) -9.831870338761206 >>> 1e6 * (1 - 1.0000103059578131504) -10.305957813150357 >>> 1e6 * (1 - 1.000010467505859646) -10.467505859645954 >>> 1e6 * (1 - 1.0000086352199331063) -8.635219933106342 >>> 1e6 * (1 - 1.0000087700957334125) -8.770095733412475 >>> 1e6 * (1 - 1.0000086206153795398) -8.620615379539842
we give a larger PPM range e.g. 11
(default is 120).
src/LTE-Tracker --gain 40 --freq 816e6 src/LTE-Tracker --gain 40 --freq 816e6 --correction $corr src/LTE-Tracker --gain 40 --freq 816e6 --correction $corr --ppm 11
LTE Cell Scanner http://www.evrytania.com/lte-tools/lte-tracker/77-lte-cell-scanner
LTE Cell Scanner http://www.evrytania.com/lte-tools/lte-cell-scanner
how to fix CMake Error at cmake/Modules/FindITPP.cmake:62 (MESSAGE): Could not find ITPP library #28 https://github.com/Evrytania/LTE-Cell-Scanner/issues/28