I bought an AP510 some time ago, at the time results were disappointing, but the firmware has improved over the years. Using 20141215 I was getting signals out to about 8 miles from the typical white stick omnis like Diamond X50, and up to 20 miles from near Chagford on Dartmoor when it was mounted in a backpack. As you can see from the header picture, I had a great RF takeoff and not much vegetation in the way from pedestrian height 😉
Thank you G6SQX and G0MAS for running high performance APRS IGates! The difference in performance with the antenna taped to the fibreglass shell at the back of my campervan is visible in the paucity of reports near G0MAS around Uffculme, range was only a quarter of that as a pedestrian. Despite having steady power and a USB lead as a counterpoise to the aerial. Maybe taping the aerial to the fibreglass detuned it, this thing is marginal enough at 1W output.
Some of the idea of getting this was to play with radio on the hills so it’s good that it performs better in pedestrian mode. I’d like to have a better feel of why exactly that was.