>Are they supposed to be in 400ms long packets? Well that is supposed to be the maximum time a FHSS is allowed to dwell in a channel according to the FCC, so it makes sense.
>Do they use a slow FSK modulation? According to the FCC test report is uses a CC1020 chip modem which in its data sheet says it can use slow FSK. > What daughterboard are you using? Have you modified the FPGA? WBX and nope. > First there is a short burst I not sure about I was thinking about using a 400ms hop time and I realized how long it would take for synchronization to occur listening to any one frequency, what I would do is use a quick burst on a listening frequency to sync. That may be what that is? > I read the time ruler in reverse. Yeah it's strange, the waterfall is flowing up away from the spectrogram ( as is should ), baudline is counting ms back in time form the present ( I'm scrolling back in time to find the burst ). I think I now need to find another old gameboy so I can start a conversation between them to see if messages are plain text. I am currently just probably getting the one announcing its presence signal. Thanks ~Andrew On Mon, Jul 2, 2012 at 9:36 PM, Michael Ossmann <m...@ossmann.com> wrote: > On Mon, Jul 02, 2012 at 08:27:01PM -0400, Andrew Davis wrote: >> >> Really cool presentation! Thanks for the info. Now i'm running into >> another problem, I sample at about 4MSPS for a bit and try to capture >> the signal as it passes though my window, but I never seem to get it, >> just a huge mess of noise, aliasing and ghosts. >> http://i.imgur.com/w3oBP.jpg > > That actually doesn't look so bad to me. Do you know anything about the > transmissions from your target device? Are they supposed to be in 400 > ms long packets? Do they use a slow FSK modulation? Are packets > supposed to happen as often as every 600 ms? If you don't know that > stuff, try looking up the FCC test report for the device. > > You can ignore all the spurs and images in the frequency domain that are > 20 dB or more below the loudest thing going on at any particular moment. > You'll see stuff like that with a USRP, much more so when you are > intentionally aliasing. > > What daughterboard are you using? Have you modified the FPGA? > >> I really can tell what i'm looking at, doesn't look like FHSS to me. > > It does to me. First there is a short burst I not sure about, but then > there are two events of the same duration, the first was received at a > lower power than the second. The first event could be a packet outside > your band that you are not receiving properly, and the second is within > your band. Oh, sorry. I read the time ruler in reverse. > >> I did capture what I think is a sync preamble followed by FSK ( >> http://i.imgur.com/EpMim.jpg ) > > That looks beautiful! Except I think it is the time ruler itself that > is reversed, not my reading of it. The image is much lower power than > the main signal. Just ignore it. That packet is decodable by eyeball > in the spectrogram, which is kind of a rare treat. > > Throw that thing into grc and decode it! :-) > > If you need help, post the raw file shown in EpMim.jpg somewhere. _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
