I'm prototyping an IR sensor system for Radio Control vehicles. I'm looking for a narrow beam with good range that can be used in direct sunlight. Currently I've tested some Sharp IR receivers in the 36-40 khz range and emitters around 950 nm. I filter the sunlight with theatrical filters as well as baffles, but I'm looking for the greatest range I can with a 3-5mm LED emitter and receiver, preferably over 30 meters. I was thinking of a high efficiency LED around the 850 nm range, but of course I'm open to any suggestions. There are no data transfer requirements, it's just used as a switch. I only refer to a narrow beam since the requirement is extremely directional, but I can use a wider beam and mechanically scrim it down for focus.