[aprssig] Help needed: APRS receive with RTL_SDR and Direwolf

John Langner WB2OSZ wb2osz at comcast.net
Wed Aug 14 21:17:46 EDT 2019


I see several issues here.


> Dire Wolf version 1.0a

That version is more than 5 years old.  There have been a lot of
improvements and bug fixes since then,  I would recommend getting the latest
stable version.


> $ rtl_fm -f 144.39M -M nbfm -E offset 0 -g 11 -p 60 -r 24000 - |

-M   should not be necessary because it defaults to narrow fm.  "nbfm" is
not listed as a choice in the documentation.
http://kmkeen.com/rtl-demod-guide/   "fm" means narrow FM.

-g    is setting the gain very low.  " Tuner gain set to 12.50 dB."  Remove
it.

-p    is to compensate for cheap devices being way off frequency. " Tuner
error set to 60 ppm."  Remove it and experiment later if necessary.

-E offset   I don't understand what this is doing.   Remove it.


> direwolf -c direwolf.sdr.conf -r 24000 -p -D 1 -

Don't use -p option unless you understand what it means and really need it.
This would cause earlier versions to hang when used unnecessarily. 




Did you read this?
https://github.com/wb2osz/direwolf/blob/master/doc/Raspberry-Pi-SDR-IGate.pd
f  


73,
John WB2OSZ






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