Hi Gonz, don't pay too much attention to the claims of 5dB over the so called 'i'sotropic antenna as it doesn't really mean very much, you could well be better off with the SSE 1090 antenna or a RadarExtender. Almost any tuned antenna will give several dB gain over the theoretical isotropic! Some will swear by one type and someone else by another. Most of these proprietary antennas are very much of a muchness, sorry if that's not much help!!