[TheList] CCIR FENZ Selcall

Mon Jul 29 10:18:03 AEST 2019

Hi Paul,

I emailed you at the address from radio wiki, but not sure if it is correct.

Regards,

On Mon, Jul 29, 2019 at 11:00 AM Paul Saville <
radiowiki-25ef7a4b868b6000 at ephemeral.nz> wrote:

> Last Christmas holidays I came across an old post about NZFS selcall
> signalling:
>
> http://radiowiki.org.nz/pipermail/thelist_radiowiki.org.nz/2010-December/001033.html
> .
> That piqued my interest, and after figuring out that it is a variant of
> CCIR
> selcall, and 6 months of tinkering, I have a Windows command line
> program that
> uses audio dsp methods to decode the tones reasonably consistently.
>
> Is there anyone on this list who would be interested in helping with
> some testing?
>
> Development work has been done in Christchurch. I think it should work
> nationally
> but I haven't had the opportunity to test it anywhere else.
>
> You would need a Windows 7 or later PC, 64-bit, with a sound card that
> supports
> 48000 samples per second 16 bit mono. The program takes audio from the
> default recording device configured in your Windows settings. It is
> designed to
> use direct discriminator output from your receiver however it will work
> with a
> speaker or headphone connection (but take care to avoid clipping).
>
> Just to be clear, the program doesn't give direct information about
> which fire
> appliance is doing what, etc. It simply decodes the tone groups to their
> CCIR
> tone symbols. Output looks like this (it writes to stdout):
>
> CDB31FFF1400C
> C5DB3__44
> CDB31FFF1325C
> C5DB3__33
> CDCC1FFF1C00C
> C5DCC__CC
>
> I leave it as an exercise for the reader to write a script or program that
> converts the symbol groups into appliance name and status and so on. A
> python
> script using regexes would be a good approach I reckon.
>
> The current release also writes a raw PCM output file of the captured
> audio.
> I have found this useful for debugging tone groups that fail to decode. You
> will need some disk space to accommodate this file.
>
> Technically an analogue 24 kHz anti-aliasing filter is required. I am
> using the
> data connector on a Kenwood TM-G707 which works well without an
> anti-aliasing
> filter, but your mileage may vary.
>
> If you would like to try out the program please contact me directly by
> e-mail
> and I will e-mail a copy back to you. I am not distributing the source
> code at
> present; just the executable.
>
> Cheers,
> Paul
>
>
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>

-- 
Ryan Warner
ZL1RKW
Mobile: +64 27 748 9062
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