Hi we to have been getting interesting stuff at low power levels. Some one is trying to implement and RFI scanning system using a small dish to scan for RFI between 800 MHz and 1800 MHz. Using the USRP2 and DBRX and its a bit hard to tell the difference at times between the birdies in the system and RFI.
Also does anyone have a reliable estimate of the noise tempreture for the USRP2 DBRX combination? Attached is three images each image has two plots one is a linear plot the other is a logarithmic scale. One plot is the dish and LNA coupled with the log perodic antenna. The other plot is the LNA terminated, and the last one is the USRP2 terminated. The plots are just lots of little data captures stiched together. http://old.nabble.com/file/p26159950/rfi_logper_20091020b.png rfi_logper_20091020b.png http://old.nabble.com/file/p26159950/rfi_termamp_20091020.png rfi_termamp_20091020.png http://old.nabble.com/file/p26159950/rfi_termcoax_20091020.png rfi_termcoax_20091020.png Jordan J Riggs wrote: > > Folks, > > I have been trying to get a better understanding the noise characteristics > of the USRP2/RFX2400 platform. To get an idea of the noise floor at > various > bandwidths, I connected the SMA's on the RFX2400 to a 50ohm load and > averaged out the FFT at various bandwidths. Naturally, I would expect the > floor to drop at lower bandwidths (higher decimation), but this is not > always the case. For example, the floor at decim 100 is slightly lower > than > it is at 128. This is counterintuitive. The only explanation I can come up > with is some filtering quirk in the FPGA. Does anyone have any ideas? > > I've attached screenshots at decim 100 and 128. > > Thanks, > Jordan > > > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > -- View this message in context: http://old.nabble.com/USRP2-noise-floor-peculiarities-tp26067142p26159950.html Sent from the GnuRadio mailing list archive at Nabble.com. _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
