Great betko, many thanks abcd567
Alan
EXPLANATION:The RB24 feeder requires beast data on port 30005.
In Pi24 image, the pre-installed dump1090-mutability does not use default settings. FR24 feeder configures it to custom settings, which included blocking all default data input/output ports. As a result the output data at port 30005 is not available, and rbfeeder starts complaining "no data".
The blocked ports get opened when in FR24 feeder settings, in the field "Process arguments" a parameter --net is added.
You will note that there are two more parameters there
--gain -10, which sets gain of dongle (-10 is a special value, sets gain to 55 dB). Instead of -10, values between 0 and 50 are accepted. Any negetive value sets the gain to Zero (except -10 which is special case as explained above).
--lat xx.xxxx --lon yy.yyyy
This is latitude and longitude of receiver (use actual values in place of xx.xxxx and yy.yyyy). When latitude & longitude are added, the dump1090 map (ip-of-pi/dump1090/gmap.html) starts showning station marker and 3 concentric circles, centered at the station marker with radius 100nm, 150nm and 200nm. These circles are called range circles.