You don't give much information?, but a CMOS inverter isn't going to drive an IR LED very hard - if you check my PIC IR tutorial hardware you'll see how to use a transistor to drive the LED with much more current, in fact I use two LED's in series to double the output, and reduce the power wasted in the current limiting resistor.
Some IR modules reduce their gain if the modulated IR is continuous, to avoid interference from compact florescent bulbs that operate at the same frequency. Therefore they need to be pulsed at a slow rate.
You could try adding lenes , like those in the eye focus units on bynoculas
many of the homemade designs for burglar alarms used them to increase the range in the past
Pulsing the signal at a higher freq could help but ive no experiece in that area .
MY thoughts would be to drive a power transistor stage from the 4069 and add more IRs to up the power radiated.
Nigel, In your hardware section of your website where you have a circuit for IR communication, You use a 5V supply. What should be the value of the Cap (470uF) if i want to design it for two pencil cells (1.5V x 2 = 3V total). My IR remote works fine for 5V but the range is lost when i use 3V supply. I am using PIC18F2220 (if that matters somehow)
Nigel, In your hardware section of your website where you have a circuit for IR communication, You use a 5V supply. What should be the value of the Cap (470uF) if i want to design it for two pencil cells (1.5V x 2 = 3V total). My IR remote works fine for 5V but the range is lost when i use 3V supply. I am using PIC18F2220 (if that matters somehow)
No, you MUST use a current limiting resistor, and it must be very low to give decent range - not using a resistor at all is likely to blow the transistor or LED..