Yes, I saw that, and have not yet had time to look at it. I went with NOAA weather radio because it's always on and I can see a few of the frequencies which makes it a great test source ... my local hams aren't always as predictable, but channelizing your local repeaters would be a very fine use of a PFB
On Sun, Aug 2, 2015 at 11:32 AM, Tim K <[email protected]> wrote: > Just as a heads up, someone mailed this into the mailing list the other day. > I think it accomplishes exactly what you all want -- although it doesn't use > PFBs as I recall. > > https://github.com/madengr/ham2mon > > - Tim > > On Sun, Aug 2, 2015 at 2:18 PM, John Ackermann N8UR <[email protected]> wrote: >> >> Hi Chris -- >> >> Using the variables, I now have the program working in general. >> >> The channel mapping gave me some nightmares, though. I finally decided >> that you need two maps -- one for the channelizer block, where you do the >> 4,5,6,7,0,1,2,3 translation, and another for the GUI that is a simple 0..7. >> >> With that, it seems to be working well although my WBX front end seems to >> have been fried as it is more deaf than it used to be. Time to switch to >> hardware troubleshooting mode... >> >> Thanks, again! >> >> John >> ---- >> >> >> On 08/02/2015 12:10 AM, Chris Kuethe wrote: >>> >>> Thanks for pointing out the paste-o. I'll fix that. >>> >>> I'm using gnuradio 3.7.8rc1, which has helper blocks for computing >>> filter taps. You can replace them with variables: >>> >>> pfb_taps = firdes.low_pass(2.0, oversampled_width, noaa_fm_dev * 2, >>> 2500, firdes.WIN_HAMMING, 6.76) >>> lpf_taps = firdes.low_pass(1.0, hardware_rate, noaa_band_width / 2, >>> noaa_chan_width, firdes.WIN_HAMMING, 6.76) >>> >>> On Sat, Aug 1, 2015 at 5:00 PM, John Ackermann N8UR <[email protected]> >>> wrote: >>>> >>>> Thanks much for this, Chris! I look forward to playing with it, but... >>>> >>>> When I load the flowgraph on my GRC 3.7.6.1 system, I get a "Missing >>>> Block" >>>> error for each of lpf_taps and pbf_taps, triggering errors in the xfft >>>> and >>>> channelizer blocks. >>>> >>>> I also had an error in the "Multiply Const" block coming out of channel >>>> 7. >>>> but that was caused by a missing space before "else" in the evaluation. >>>> >>>> Help? >>>> >>>> But thanks so much for taking this on. It's the perfect starting point >>>> for >>>> some projects I've been wanting to work on! >>>> >>>> John >>>> ---- >>>> >>>> On 08/01/2015 03:26 PM, Chris Kuethe wrote: >>>>> >>>>> >>>>> OK, Here it is... at least, a beta version. I have yet to come up with >>>>> a concise explanation of the channel map and why you'd want to >>>>> oversample, but it is functional. >>>>> >>>>> This flowgraph would work equally well by directly connecting all the >>>>> ports together, but I'm a big fan of using virtual sources and sinks to >>>>> make the design somewhat self-documenting.. >>>>> >>>>> >>>>> >>>>> On Sat, Aug 1, 2015 at 4:55 AM, Markus Heller <[email protected] >>>>> <mailto:[email protected]>> wrote: >>>>> >>>>> Great! Thanks! I'm very curious! >>>>> >>>>> br/vy73 >>>>> markus >>>>> dl8rds >>>>> >>>>> Am Freitag, den 31.07.2015, 14:34 -0700 schrieb Chris Kuethe: >>>>> > OK, I have a mostly working flowgraph and am now adding comment >>>>> to all >>>>> > the blocks explaining why I'm doing this or that. Will publish >>>>> tonight >>>>> > or tomorrow. >>>>> > >>>>> > On Tue, Jul 21, 2015 at 11:56 AM, Chris Kuethe >>>>> <[email protected] <mailto:[email protected]>> wrote: >>>>> > > Maybe I'll do up an illustrated example on this using NOAA >>>>> weather >>>>> > > radio, or the pager band >>>>> > > >>>>> > > On Tue, Jul 21, 2015 at 11:42 AM, <[email protected] >>>>> <mailto:[email protected]>> wrote: >>>>> > >> I just use the built-in firdes stuff, rather than using an >>>>> external >>>>> > >> designer. >>>>> > >> >>>>> > >> >>>>> > >> >>>>> > >> >>>>> > >> >>>>> > >> >>>>> > >> >>>>> > >> On 2015-07-21 14:38, Marcus Müller wrote: >>>>> > >> >>>>> > >> Hi Rich, hello Markus, >>>>> > >> >>>>> > >> On 21.07.2015 19 <tel:21.07.2015%2019>:51, Richard Bell >>>>> wrote: >>>>> > >> >>>>> > >> GNU Radio has channelizers built-in, but I've not used them >>>>> yet, so I don't >>>>> > >> know how far they take you into this kind of task. >>>>> > >> >>>>> > >> the Polyphase channelizer is actually an implementation >>>>> derived from that >>>>> > >> school of thought, and it works amazingly well. >>>>> > >> In fact, in preparation of a presentation at a certain ham >>>>> conference, I >>>>> > >> tried using it to get 20 PMR/LPD channels out of a 1MS/s >>>>> signal in real >>>>> > >> time, and then just shuffle them around, before feeding them >>>>> back into the >>>>> > >> inverse synthesizer PFB. >>>>> > >> >>>>> > >> It's pretty easy: >>>>> > >> Design a single low pass filter, as if you just wanted to >>>>> filter out the >>>>> > >> channel which is centered exactly at your RF center >>>>> frequency, >>>>> i.e. 0Hz, >>>>> > >> with the full sampling rate [2], using the gr_filter_design >>>>> tool. Play >>>>> > >> around with the different window types[1], and bear in mind >>>>> that the >>>>> > >> suppression outside your desired passband needs to be high >>>>> enough so that >>>>> > >> the sum of the energy in all other channels don't hurt your >>>>> channel too >>>>> > >> much, but don't overdo it (60dB suppression should be >>>>> enough). >>>>> > >> Now you get a long filter. Copy and paste the filter >>>>> coefficients from >>>>> > >> gr_filter_design to your PFB filter taps property. >>>>> > >> Set your channelizers number of channels according to your >>>>> plans -- 40, if >>>>> > >> you want to get all the 40 25kHz channels in 2MHz. You get a >>>>> block with 40 >>>>> > >> outputs! >>>>> > >> Explaining things like channel mapping is best done by >>>>> pointing you at the >>>>> > >> official documentation: [3] >>>>> > >> >>>>> > >> >>>>> > >> Greetings! >>>>> > >> Marcus >>>>> > >> >>>>> > >> [1] Hamming is not always the best choice, I'd try that, >>>>> Blackman-harris, >>>>> > >> and Kaiser. I personally like harris in this case -- we want >>>>> to get a full >>>>> > >> channel, two adjacent channels are usually not occupied, and >>>>> as soon as we >>>>> > >> pass the stopband frequency, we're basically at -100dB. >>>>> > >> [2] assuming you want to use 2MS/s for your 2MHz wide band, >>>>> 2MHz sampling >>>>> > >> rate, and assuming 25kHz wide channels, 12.5kHz cut off >>>>> frequency, 25kHz >>>>> > >> start of stoppband. I get something like 440 taps. >>>>> > >> [3] >>>>> > >> >>>>> >>>>> >>>>> https://gnuradio.org/doc/doxygen/classgr_1_1filter_1_1pfb__channelizer__ccf.html >>>>> > >> >>>>> > >> _______________________________________________ >>>>> > >> Discuss-gnuradio mailing list >>>>> > >> [email protected] <mailto:[email protected]> >>>>> > >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>>>> > >> >>>>> > >> >>>>> > >> _______________________________________________ >>>>> > >> Discuss-gnuradio mailing list >>>>> > >> [email protected] <mailto:[email protected]> >>>>> > >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>>>> > >> >>>>> > > >>>>> > > >>>>> > > >>>>> > > -- >>>>> > > GDB has a 'break' feature; why doesn't it have 'fix' too? >>>>> > >>>>> > >>>>> > >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> -- >>>>> GDB has a 'break' feature; why doesn't it have 'fix' too? >>>>> >>>>> >>>>> _______________________________________________ >>>>> Discuss-gnuradio mailing list >>>>> [email protected] >>>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>>>> >>>> >>>> _______________________________________________ >>>> Discuss-gnuradio mailing list >>>> [email protected] >>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>> >>> >>> >>> >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> [email protected] >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > -- GDB has a 'break' feature; why doesn't it have 'fix' too? _______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
