> > Yes Jeff- good feedback but I am still working on that comment that mode S is > only required above 18000' , most folks around here (within 30 miles of a > major airport) seem to think that we will need it at all altitudes. > Bill > -----------------
That is not the case in the US. The 2020 rule requires ADS-B out. You are allowed to equip with either (Mode S) 1090-ES or UAT out. Other planes with ADS-B in will see either, as will the FAA. The Mode-S is received by Radar and the UAT is received by the ADS-B towers (they look like a little outhouse with a small antenna). In a congested area like the San Diego and Los Angeles areas it shouldn't make any difference as the FAA has lots of ADS-B towers. However, in remote areas, it does make a difference. Flying internationally (like crossing into Mexico or flying into Canada), or flying at or above 18,000', you will be required to have 1090ES. On our trip last weekend, I was flying my KR and broadcasting UAT out. My buddy flew the exact same route at the exact same altitude in an RV-7A using a Dynon feeding a headless Trig TT22 Mode S transponder. We flew direct from KRYN (Tucson) to KLAM (Los Alamos [near Santa Fe]). The report for his Mode-S transponder showed the complete flight from Tucson to Santa Fe. My report only showed the last hour of the flight. We were flying over a very remote and desolate area for most of the flight. But what the reports showed is that they saw him on radar for the whole trip. My ADS-B out (and In) was out of range from an ADS-B tower for over half of the trip. Of course I was also able to see the RV-7's 1090ES transmissions and was tracking him on my GPS. -Jeff Scott Los Alamos, NM