2 kHz offset is within tolerance for 1900 MHz. Locking to a stable 10
MHz reference, generally an OCXO or GPSDO, is the recommended
approach.
I applied external 10MHz reference, the best I had at hand.
Now kalibrate says I have about 200Hz offset at 900MHz and 420Hz at
1800MHz, but phones still do not want to register to OpenBTS. A few
phones that did not see the network before, are now seeing the network.
They see the network, but they say “no access” when I try to register. I
configured OpenBTS to allow everything to register with no restrictions.
The same computer was working with B100 a few weeks ago without any
problems. I now have a few B200 but none of them works. They all behave
the same way.
Is there a point in going for a more accurate clock ? I am already below
500Hz at 1900MHz.
Did anyone get OpenBTS working on B200 ?
In the log I see regular “Sample buffer: Overrun”. Can I do anything
about it?
There is no sign in OpenBTS log that a phone is trying to register.
May 14 13:33:29 lenovo-Edge transceiver: ERR 139674597304064 13:33:29.0
UHDDevice.cpp:780:readSamples: Sample buffer: Overrun
May 14 13:33:30 lenovo-Edge transceiver: ERR 139674597304064 13:33:30.9
UHDDevice.cpp:780:readSamples: Sample buffer: Overrun
May 14 13:34:29 lenovo-Edge transceiver: ERR 139674597304064 13:34:29.0
UHDDevice.cpp:780:readSamples: Sample buffer: Overrun
May 14 13:35:29 lenovo-Edge transceiver: ERR 139674597304064 13:35:29.0
UHDDevice.cpp:780:readSamples: Sample buffer: Overrun
May 14 14:42:40 lenovo-Edge transceiver: DEBUG 140528251016960
14:42:40.0 UHDDevice.cpp:737:readSamples: Requested timestamp = 792.358
May 14 14:42:40 lenovo-Edge transceiver: DEBUG 140528251049728
14:42:40.0 Transceiver.cpp:774:driveTransmitFIFO: radio clock 5:1319506
May 14 14:42:40 lenovo-Edge transceiver: DEBUG 140528251016960
14:42:40.0 Transceiver.cpp:358:pullRadioVector: looking for TSC at time:
1:1319505
May 14 14:42:40 lenovo-Edge transceiver: DEBUG 140528251016960
14:42:40.0 Transceiver.cpp:358:pullRadioVector: looking for TSC at time:
2:1319505
May 14 14:42:40 lenovo-Edge transceiver: DEBUG 140528251016960
14:42:40.0 Transceiver.cpp:358:pullRadioVector: looking for TSC at time:
3:1319505
May 14 14:42:40 lenovo-Edge transceiver: DEBUG 140528251016960
14:42:40.0 UHDDevice.cpp:737:readSamples: Requested timestamp = 792.36
May 14 14:42:40 lenovo-Edge transceiver: DEBUG 140528251049728
14:42:40.0 Transceiver.cpp:774:driveTransmitFIFO: radio clock 7:1319506
May 14 14:42:40 transceiver: last message repeated 2 times
May 14 14:42:40 lenovo-Edge transceiver: DEBUG 140528251016960
14:42:40.0 UHDDevice.cpp:772:readSamples: Received timestamp = 792.357
May 14 14:42:40 lenovo-Edge transceiver: DEBUG 140528251016960
14:42:40.0 Transceiver.cpp:358:pullRadioVector: looking for TSC at time:
4:1319505