Hi all. I've just joined out of general interest and very interesting it is too. My line of site to LTN is where a/c are still below 300 feet and generally they do not show on PlaneFinder. I actually see them pass my line of site from home when taking off but they generally do not show on the screen until after this. When landing they freeze on screen at about the same height until they just vanish! Admittedly on odd occasions they do show on the ground but then at the time of take off they jump in one step to around 300 feet. Is there a local transmission problem or am I expecting too much? Sorry I'm just another ol' git playing with things I don't really understand! Cheers Trev.