tetra June 2011

tetra@lists.osmocom.org

5 participants
4 discussions

Chaosradio Express #183 on TETRA
by Harald Welte 24 Jun '11

24 Jun '11

Hi all, The latest Chaosradio Express (CRE) episode has just been released, and it is about trunked radio, TETRA, security aspects and the Osmocom TETRA project. http://chaosradio.ccc.de/cre183.html (and yes, it's German, like all CRE episodes...) -- - Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)

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experience with fcdp
by Harald Welte 04 Jun '11

04 Jun '11

Hi! I've borrowed a Funcube Dongle Pro and tried to use it with osmocom-tetra. I've manually tuned it to a tetra carrier using the Qt-GUI, and it I can see the carrier very clearly in the spectrum/fft. However, I'm getting many more bit errors than with a USRP2+WBX board. Also, I have the feeling that the WBX has a much higher sensitivity, even with the FCDP input LNA at 30dB maxed out. Can anyone confirm these findings? I'll do some more investigation and report back here. Regards, Harald -- - Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)

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UHD based demod script
by Clemens Hopfer 04 Jun '11

04 Jun '11

Hi, I've modified the usrp2 script to use the UHD gnuradio driver for new USRP (UHD-only) hardware. It seems to work with my N200+WBX setup, but gnuradio is pretty new to me, so there might be some bugs. Since I'm using the WBX my antenna port is 'TX/RX'. I'm not sure if this is a good default value, it's configurable though. Clemens Hopfer

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Fun Cube Dongle Pro internals
by Harald Welte 02 Jun '11

02 Jun '11

Hi! For those interested, I've taken apart the case and did some investigation how the FCDP hardware architecture looks like. The results are available at http://tetra.osmocom.org/trac/wiki/Funcube_Dongle It seems the silicon tuner actually is intended for DVB-T, thus the bandwidth it can down-convert is _much_ higher. However, the audio codec that they use can only do 96kHz. That's actually really sad. I wish they had used something with higher ADC rate. But it seems like even high-end audio codecs never get you beyond 196/216 kHz - still insufficient for e.g. GSM. Regards, Harald -- - Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)

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tetra June 2011