Hi Alan / Roger
I also agree wholeheartedly! My own tests have proved that PAW ADSB works extremely well - easily identifying the big boys (girls) and those (very) few GA around locally with ADSB out. The forthcoming new p3i RF will no doubt bring in more aircraft we will be able to 'see', particularly within local microlight or GA clubs, but that will still leave a huge number of aircraft, both private and commercial (helicopters etc.) who's owners have invested in expensive transponders, but many of whom are for various reasons very unlikely to add PAW systems in their aircraft.
As well as contributing to earlier posts along this vein, I had a fairly long chat to Lee and Dave Styles about transponder detection at the show. As has been said in other posts, PAW already receives transponder signals and if transponder equipped aircraft are about these can be seen in your traffic log. The difficulty Lee has is in working out how to present them on screen, as raw transponder signals contain no location information so determining range is difficult and direction impossible (other than with complex multi-aerial systems).
Systems like POWERFLARM and the now defunct ZAON work out an approximate ' range' i.e. distance from your aircraft to the transponder equipped aircraft by extrapolating from the signal strength of the received transponder signal, but this is very difficult to do accurately, often resulting in 'ghost' alerts, which I know Lee is keen to avoid. In the case of POWERFLARM the presence of a transponder equipped aircraft is shown as a bearingless target either above or below your own aircraft. With the ZAON PCAS an approximate range is given as well as height above or below your aircraft, together with an indication as to whether the aircraft is climbing or descending. As a long term ZAON PCAS user (since 2009), I have found it to be a life saver on several occasions and am prepared to put up with the infallibility of poor range accuracy and complete lack of directional information (also common to POWERFLARM) for the benefit of getting a positive alert that there is another aircraft 'nearby', with the information that it is above or below me or even worse at the same level (easily decoded from mode C or S) which helps me to find and avoid it. Yes I have had false alerts - probably caused by high powered transponders confusing the logic, but rather that than have an aircraft fly right into me with it's transponder pumping out a loud warning that it was there.
In view of the fact that probably 95%+ of those (light) aircraft which have transponders don't transmit ADSB, that leaves a massive group of aircraft out there which PAW in it's soon to be current form still won't help us to 'see'.
In closing I fully understand Lee's concerns about not being able to provide accurate range/direction information from raw transponders as I have heard all the negative comments about the ZAONs over the years, but as I said to Lee at the show, IMHO any notification that there is another aircraft close by is better than nothing! Perhaps we need to look at it on the basis that unlike the present ADSB which appears on the tablet at distances of up to and even over 100 miles, raw transponder alerts could be limited to a signal strength that would equate to say 5-10 miles or even less, with relative altitude simply as a 'get your eyes out of the cockpit and look for me' alert
Hope this promotes further thought in this area. I for one would welcome this type of development and have already offered Lee any help I can provide to help move this forward.
Best regards to all.
Peter
