add note for rtl-ais

docs/install.md

@@ -107,3 +107,8 @@ mix help pyairwaves.update_aircrafts
 - pyairwaves.update_translations: one time per month
 - pyairwaves.update_aircrafts_mode_s: one time per month
 - pyairwaves.update_aircrafts_mode_sogn: one time per month
+
+# rtl-ais
+
+Uses this fork: https://github.com/mik3y/rtl-ais until https://github.com/dgiardini/rtl-ais/pull/34 is merged.
+We need the mode to keep TCP socket open or it won't update the AIS messages.

installation/rtl_ais.service

@@ -3,7 +3,8 @@ Description=AIS receiver and decoder
 After=network.target
 
 [Service]
-ExecStart=/usr/local/bin/rtl_ais -d 0 -T
+# device 0, TCP, keep socket open, RTL AGC, Tuner gain 30, print NMEA to console
+ExecStart=/usr/local/bin/rtl_ais -d 0 -T -k -R -g 30 -n
 Type=simple
 RestartSec=5
 Restart=on-failure