G'day, I managed to capture the spectrum emitted by NOAA-12 for its entire pass; not quite sure anymore which one it was. Using a Diamond D130 discone antenna and a low noise broadband power amplifier (10-2000MHz, g=20dB, nf=3.5, po=+20dbm!!!) the signal was recorded utilizing the usrp_rx_cfile.py python script, a gain of 100, and decimation of 250 centered on 137.5MHz. It produced a very large file
-rw-r--r-- 1 root wheel 1117519872 Dec 9 20:01 noaa-12.dat This a little more than 1GB!!!! and 419MB zipped. Do we have a place were it can be uploaded for other list members that are interested? My bandwidth isn't large enough to offer it to public from here. I was surprised how loud the signal was, considering the equipment used here, and how well the TVRX card performed. Now I'm really looking forward to shooting the big birds = geostationary satellites. BTW: Do we have an AFC block to compensate for doublershift or is this something we still need to implement? I looked through the documentation but failed to find anything there. cheerio Berndt On Saturday 09 December 2006 16:52, Berndt Josef Wulf wrote: > G'day, > > I'm looking for raw data. Don't you use the usrp_rx_cfile.py script to > capture frequency spectrum? > > e.g.: ./usrp_rx_cfile.py -d 32 -f 137.5M > > You may need to play with the options -R, -g, -N (subdev, gain and number > of samples) depending on your setup where > > -R [A|B] site where the tvrx is plugged in > -g <0..115> gain (default is mid-point @ 58) > -N <positive int> number of samples (e.g samplerate * record time in sec) > > I usually have to specify the frequency and the decimation. > > I want to write my own decoder and an image sink to ultimately display the > pictures received and hence audio files want do the trick. > > cheerio Berndt > > On Saturday 09 December 2006 14:29, Bill Tracey wrote: > > Berndt, > > > > I can grab some APT audio with a USRP and Bob McGwier's rx apt code. > > Or are you looking for the raw data coming off the TVRF -- could probably > > do that as well but will need some pointers as to how to grab the raw > > sample off the TVRF card -- suppose one just takes the rxapt python code > > and hacks it to dump to a file sink? > > > > I've also got a Hamtronics R139 I can grab audio from -- although it's > > gotten a bit deaf of late. Pics from it can be seen @: > > http://oddjob.yi.org:8888/wxpics/index.html > > > > Regards, > > > > Bill > > > > At 10:44 PM 12/8/2006, you wrote: > > >G'day, > > > > > >Ok, let's try it this way: > > > > > >Is there someone with the equipment and time to record APT signals > > >transmitted > > >by NOAA satellites in the 137MHz band? Alternatively, geostationary > > > weather satellites transmit WEFAX pictures at around 1691MHz (Hey, were > > > are the guys that tuned into GPS spectrum which is right next door... > > > :-) > > > > > >I want to demodulate the AM/FM 2400Hz sub-carrier signal and display the > > >image. Currently I'm not in the position to capture the spectrum myself > > > due to lack of equipment but this is about to change. > > > > > >I can provide info on satellite passes and frequencies for your > > > location. > > > > > >cheerio Berndt > > > > > >On Wednesday 06 December 2006 14:20, Berndt Josef Wulf wrote: > > > > G'day, > > > > > > > > Has anyone sampled NOAA or METEOR signals in the 137MHz spectrum > > > > which they wouldn't mind sharing the spectrum data file(s)? > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio