Re: [Discuss-gnuradio] Updated NBFM Recorder

[Tom Rondeau]

On Sun, Jun 15, 2014 at 12:28 PM, madengr <address@hidden> wrote:

I actually started with that, but the US 2 meter "suggested" channels are
either 15 kHz or 20 kHz spacing depending on location.  It's interesting to
dump all the 2 meter repeater traffic in my city to disk for several days.
Even the busy ones are only active about 2 hours/day.  Unfortunately the 800
MHz public saftey band is so wide it's difficult to capture many channels,
and they are P25 anyway.  I patched in the DSD P25 decoder, but it can only
handle two channels simultaneously.  The public safety channel spacing may
work well with the pfb_channelizer.

Thanks,
Lou
KD4SHO

Gotcha. That makes sense. Thanks for the explanation.

There are ways to handle this situation of non-equal bandwidths, but I'd wonder if it's more complicated for this project than it's worth (using the concept of the reconstruction filters). Could be a good testing ground, though, to build a system that channelizes the entire band, does some signal detection for those channels that are active, figures out their channel bandwidth, and pulls them out or reconstructs them as necessary. It's a pretty advanced use of the PFB channelizers, though, so it's not a trivial experiment to just run.

Nice work!

Tom

 

Tom Rondeau-2 wrote

> Nice work.
>
> I recommend seeing if you can replace the bank for xlating_fir_filters
> with
> a pfb_channelizer_ccf block. This should be more computationally efficient
> than all of the xlating filters, so I'd really like to see if that's true
> for you app.
>
> Tom
>

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