OK, Here it goes.
1. Which Brand cars are they? Tomy/Microsizers seem to have less range than most clones.
2. What frequency is your and your friends car on. In my experience MHz cars have less range than the other frequencies (35-40-45-49-57).
You can try a few steps to increase range.
Lengthen the antenna on the car. I use Cat5 wire (the type that's inside computer network cables) and make a 10" antenna. I've also heard god things about using a #9 metal guitar string for the antenna.
Check for cripple caps. The cripple cap (a chip on the board) in the car may or may not effect the range. I've had cars increase the range by a few inches to several feet by removing the car's cripple cap. Instructions are on
QFM web site. Some controllers have cripple capacitors in them that will limit the range you can control the car.
Outside interference. Florescent lights, computers, fans, portable heaters, etc. can affect the range of the car when running close to them.
Linear Mode
