These are ADS-B broadcasts sent for conspicuity from something that does not have a full Mode S transponder and can’t reply to Mode S interrogations. Commonly seen from e.g. ground stations / stationary obstacles / unmanned balloons / ground vehicles.
Hi all, (SkyEcho2 device in either UK or Australia)
When you see something like that on an aircraft, glider, or hot air balloon it is probably a SkyEcho2 device. They are portable devices for aircraft that have no transponder, mode-a/c, or mode-s. They broadcast their position as DF18, which is normally ADS-R rebroadcast traffic and will not be interrogated by ATC as OBJ said above.
Last month on the PlanePlotter side, we were lucky enough to have one of our PlanePlotter users testing his SkyEcho2 on 3 different hot air balloons in the UK. Very quickly we used the test to determine the data type, which was later confirmed by the SkyEco2 online documentation. At first, we didn’t know it was actually a SkyEcho2.
SkyEcho: They are only authorized to transmit in the UK and Australia.
That’s interesting, it has ADS-B and UAT bands! Obviously they will target the US market when they will pass the certifications.
The 20W of transmit power is similar with UAT “Low Power” levels in US:
A0 “Aid to Visual Acquisition” and A1L “Conflict Avoidance”.