Hi Chris,
Re your earlier post...
Have you read the section in the Operating Instructions about PAW’s Visual and Audio Alerts? If not, please do so. You can find the information on pages 28 - 30 of it here...
https://pilotaware.com/Documents/Operating%20Instructions%2020190621.pdf?_t=1561197960For ‘known position’ aircraft (i.e. PilotAware, ADSB, or FLARM/Mode-S/3D Rebroadcast), Audio Alerts report the aircraft’s position as it ‘breaks in’ through any of the boundaries of one of the three warning cylinders around your aircraft. These alerts are then repeated if the aircraft continues to close with your own either horizontally or vertically.
For ‘Bearingless’ Traffic i.e. pure Mode-C or Mode-S transponders, with no ‘range’ data the alerts are given in a different format, indicating degree of perceived risk and relative altitude, such as ‘Traffic Notice 500 feet below’. Whether or not you receive these alerts depends on your ‘Mode C/S Horizontal Sensitivity’ and ‘Mode C/S Vertical Display Range’ Settings on your PilotAware / Configure Screen - (see pages 13 - 14 of the Operating Instructions).
In your video, the first ‘Bearingless Target’ alert - at 0.46 reports a fairly strong signal (hence ‘Danger’) from 1000ft below. This alert wasn’t preceded by a typical ‘Notice’ or ‘Alert’ warning as the aircraft approached and is typical of a first alert from a high power CAT transponder - probably from an aircraft on the ground at a nearby airport. The following report ‘Notice’ at 1200 ft below indicates that the risk is reducing - because you and the aircraft are moving apart (I’m guessing you had your Mode C/S Vertical Display Range set at +/- 2000ft). You
can reduce the likelihood of these high power alerts by reducing your ‘Mode C/S Horizontal Sensitivity’, but this will also reduce warnings from closer GA aircraft, so better IMO to learn to recognise this ‘signature’ - i.e. a sudden ‘Danger’ warning without a prior ‘Notice’ or ‘Alert’ message as High-Power CAT at distance, which you can generally ignore
PROVIDING THE REPORTED RELATIVE ALTITUDE ISN’T CLOSE TO YOUR OWN.
Edit: I meant to add - the Traffic ‘disappearing’ at close range as it passed behind you was almost certainly due to screening between your two aircraft’s antennas which can be caused by aircraft engines, bodywork, undercarriage, pilot and passenger bodies or simply sub-optimal antenna placement in either aircraft.
Other than that, the system has done exactly what it was designed to do.
I hope this helps explain what was going on.
Regards
Peter