Furuno AIS Headers

[swampbush]

Hi all, first post here so hope this is OK.  I searched but can't find any answers.  I have been using OpenCpn for windows with a Furuno FA50 AIS which has the option to ignore the headers that Furuno put on the navnet.  
From the OpenCpn manual https://opencpn.org/wiki/dokuwiki/doku.p...onnections

Configurable Null header acceptance on UPD receiver for Furuno[url=https://opencpn.org/wiki/dokuwiki/doku.php?id=opencpn:opencpn_user_manual:options_setting:connections#configurable_null_header_acceptance_on_upd_receiver_for_furuno][/url]

Most, if not all Furuno equipment sending data over UDP is including a binary header at the beginning of the packet payload causing the data not to be parseable as normal NMEA0183 datastream directly. Since the 4.8.2 release, it is possible to configure OpenCPN to handle this problem by editing the opencpn.ini configuration file in the [Settings] section to add the line
EnableUDPNullHeader=1


This works fine on windows, but can I do something similar for OpenCpn on a Raspberry Pi 4.  I have OpenCpn 5.2.4 running succesfully on the Pi.  Bit of a struggle as it is my first time using a Pi.  I can't find an opencpn.ini file anywhere on the Pi.

I want to use the Pi without the laptop, primarily as a roaming shore station for marinetraffic and as an NMEA server for tablets etc on the boat.  If OpenCpn on a Pi can't filter the headers, can something else do it?  Maybe Signal K.
cheers
Peter

[swampbush]

Hi, I managed to answer my question and I found the config file, from the link in the about screen. Took a chance and put the EnableUDPnullheader=1 line and that fixed that up. I can now see my Furuno AIS targets. Had a bit of trouble working out why I couldn't use it as an NMEA server to my other devices, but it appears that UDP broadcast needed to be in the form of 172.31.255.255 not 172.31.x.x I think. New at this, guessing a lot.