I ordered a couple of the Laipac transmitter receiver combos. They are incredibly easy to use and I have gotten 3 different flavors working so far. My concern is the confusing data sheet concerning the transmitter antenna coupling spec. The data sheet seems to imply that proper transmit power is achieved only into a 50ohm load. Is a 1/4 wave or 1/2 wave piece of wire for an antenna providing the correct load? Can anyone at Sparkfun get some real info out of Laipac? I haven’t had a response yet.
A 1/4 wave whip will have as close to 50 ohms as you are going to get. There should be a counterpoise attached to the ground connection of the antenna terminal too. Thus, you will have a 1/2 wave dipole. Think of the top 1/4 wave whip as needing something to push against. If the board ground plane is less than 1/4 wave long, a second 1/4 wave whip will aid signal propegation greatly. It will also make reception better.
Ron