QRP...running with  5 watts or less
CW (morse code)or Phone(AM or SSB)
Home built , built from a kit or bought

The enjoyment of building your own rig at a fraction of the cost of purchasing a large one.

Why QRP??
Challenge of  operating your own station.
Building your own gear from kits or homebrew
Construct your own antennas and feedlines
Operating skills-1 watt is 3 S units weaker than a 100 watt rig
Commercial gear available-Heathkit,MFJ,Ten-tec,You-kits etc
Contests-Bonus multipliers for QRP operation
QRP clubs-who offer advise,ideas,projects to build and contests
QRP Fox hunts
Longest distance-2640Km (1650 miles) with 1 uW (1 microwatt) on 10M
Portable-small size-easy operation  with small batteries
Low cost $$