April 2012 - osmocom-sdr - lists.osmocom.org

rtl-sdr with airprobe
by schwandre＠gmx.net 02 Apr '12

02 Apr '12

Hi! I tried to use the recorded capture.bin of several arfcn with aiprobe. Checked the arfcn before with cell-log of osmocom. I converted the capture.bin to the cfile format with the rtl2832-cfile gnuradio block. checked the converted recordings with fft-gui of gnuradio. Seems to be fine. Now i used gsm-receiver with the follwing option to decode the broadcast traffic that is in ts0: GSM/airprobe/gsm-receiver/src/python$ ./go_usrp2.sh capture.cfile 174 0b with the downloaded samplefile of srlabs it works fine, but with mine not. i also tried to change the dezimation rate, did not help. i recorded the bin file with 1.8MS/s also did some tests with 200kS/s. How do i calculate the dezimation rate for the different MS/s ? I think it should work when i use 1.8MS/s and decimation rate of 174. What i am doing wrong? I am using the Hama Nano and the terratec noxon, both are working fine, tested it on radio-broadcast 88-108 MHz and 433 MHz ISM-Band. Will be thankful for any hint. Bye! -- Empfehlen Sie GMX DSL Ihren Freunden und Bekannten und wir belohnen Sie mit bis zu 50,- Euro! https://freundschaftswerbung.gmx.de

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Si5170 replaceable with SI514 ????
by Heikki Ylipiessa 02 Apr '12

02 Apr '12

Hi. I know that the Si570 is high precision oscilator ... And it mainly covers the frequencies quite well . But .. the 10MHz lower limit cuts the possibility of using it for 1.8MHz and 3.6Mhz and 7.0 MHz HAM radio bands ... The SI514 would possibly cover the need .. As I don't know how solidly the design has been made ... I'm asking if the Si570 can be replaced with SI514 and if so does the device firmware also need adjusting ??? -- Regards , Heikki Ylipiessa Home: heikki(a)ylipiessa.fi Work: heikki.ylipiessa(a)fi.ibm.com

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RTL-SDR: E4000 IF bandwidth
by Michał Rogala 01 Apr '12

01 Apr '12

Hi! I've just noticed one issue about E4000 driver that bothers me - IF bandwidth at the chip is set to 8 MHz, where maximum bandwidth of RTL2832U sampling is 3.2 MHz. Wouldn't reducing IF bandwidth at tuner chip improve overall sensitivity (and maybe noise level)? best regards Michal Rogala

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