Moving object (object picked up by drone) will need to be small and=20 light, which is why I was thinking it would be better to transmit.=20 Correct me if I'm wrong, but to get better reception I'd expect the=20 receiver to have a large-ish antenna, and to get better range, I'll go=20 with a lower frequency, which means larger antenna. Hence why I've been=20 initially looking at it in this direction, but yes I should investigate=20 both options. Cheers, -Neil. On 10/7/2019 11:18 AM, louijp@gmail.com wrote: > Neil, do the opposite. Power Calibrated beacons with frequencies close bu= t distinct around the field, and SDR receiver on the mobile. Now use GPS p= rinciple to get your location. The beacons replace the satellites. > Just an idea,Jean-Paul N1JPL > > Sent from Yahoo Mail on Android > =20 > On Mon, Oct 7, 2019 at 10:50 AM, Chris Roper wrote:= Wouldn't RDF be easier. > If two receivers can detect an angle then the position is simple trig. > >> --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .