1724Re: APRS-IS Rx-only iGate with rtl dongle
- May 19, 2013Hi Mathison,
multimonNG needs an sample rate of 22050 Hz so you have to add -s 22050 to the commandline. You also need to add a "-" at the end of rtl_fm to get the data an the stdout.
sudo rtl_fm -f 144390000 -s 22050 - | multimonNG -a AFSK1200 -t raw /dev/stdin
It's also recommended to get the ppm with the kalibrate tool and add the ppm to rtl_fm with the -p option. I also use the -g option to set up the maximum gain based on the antenna.
If you don't want to use the sudo command you have to install the rtl-sdr.rules into /etc/udev/rules.d/ folder. Then the normal user can use the rtl dongle.
--- In Raspberry_Pi_4-Ham_RADIO@yahoogroups.com, "mathisono" <mathisono@...> wrote:
> sudo rtl_fm -f 144390000 | multimonNG -a AFSK1200 -t raw /dev/stdin
> This dosent yeald 144.390mhz????
> multimonNG (C) 1996/1997 by Tom Sailer HB9JNX/AE4WA
> (C) 2012 by Elias Oenal
> available demodulators: POCSAG512 POCSAG1200 POCSAG2400 EAS UFSK1200 CLIPFSK AFSK1200 AFSK2400 AFSK2400_2 AFSK2400_3 HAPN4800 FSK9600 DTMF ZVEI SCOPE
> Enabled demodulators: AFSK1200
> Found 1 device(s):
> 0: Generic, RTL2832U, SN: 77771111153705700
> Using device 0: Generic RTL2832U (e.g. hama nano)
> Found Elonics E4000 tuner
> Oversampling input by: 42x.
> Oversampling output by: 1x.
> Buffer size: 8.13ms
> Tuned to 144642000 Hz.
> Sampling at 1008000 Hz.
> Output at 24000 Hz.
> Exact sample rate is: 1008000.009613 Hz
> Tuner gain set to automatic.
> something is off! the input sxntax is diffrent. as seen on the RTL site.
> For example, the following command will do reception of commercial wide-band FM signals:
> rtl_fm -f 96.3e6 -W -s 200000 -r 48000 - | aplay -r 48k -f S16_LE
> On a Mac, a similar command that works is as follows. This assumes that the sox package is installed, 'port install sox':
> rtl_fm -f 90100000 -W -s 200000 -r 48000 - | play -r 48000 -t s16 -L -c 1 -
> Im not sure were the problem resides? Ive never encountered this, as that ive only used the tcp_server, ive never had SET the RTL to a specific FRZ. 144.14e6 results in: 144392000 Hz.
> 73 Mathison
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