On 10/5/17, Steve <coupaydevi...@gmail.com> wrote: > You might also do your testing in a more remote spot. The use of ISM > in the city is probably pretty high, and interference would be an > issue. It might not break the squelch (spread spectrum, etc), but the > bits would be corrupted. > > I see a lot of users on that band, with just a junkbox antenna and > SDR, and I'm in a residential area. > > 73/Steve >
Hi Steve, Actually, there was not much noise on those particular frequencies at that time. I know because I could monitor the signals on the spectrum scope in a 1 MHz bandwidth around my frequencies of interest (doing this on a cellphone with limited screen estate is quite challenging). I plan to repeat the test in a more organized fashion on 5 GHz and 2.4 GHz. I expect better performance and reliable 1 square km coverage with the following setup: 1 milliwatt transmitter into 16 dBi sector antennas and 6 dBi RX antennas (with and w/o diversity). I will process the data and hopefully make it available before the SDRA conference in July next year for interested parties. I recommend reading ETSI ETR 300-1 for details on the test methodology. Resistance to wideband interference from 802.11x and avoidance of other narrow band signals like 802.15 is one of the goals. SDR allows us to monitor several MHz of spectrum and choose the channel with the best SNR. One simple way to do this is a multichannel modem with OFDMA, where active carrier allocation is done based on noise sensing. Cheers, Adrian ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Freetel-codec2 mailing list Freetel-codec2@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freetel-codec2
