Merlin

Longer range...

Signal - Aerial is the better amplifier, because has no noise. No amplifier can do this what we can improve with the aerials. The wireless signal on the higher frequencies is like the light - where you can't shine, there you can't transmit. Of course this isn't 100% true, but each resistance brings the signal down. If you want to twice the range, you've to increase the transmission power 16times (!) or easy put the receiver on a better place. Each feet above the ground can make wonder in the range.

Aerials - All the new products have BNC connector on the wireless transmitter/receiver so you can easy change the basic aerial with the high-gain. You don't need to have the same aerials on both modules (transmitter and receiver). But if you use the high-gains on both ends of the transmission line, it's the best way.

Omnidirectional or directional? If you have another strong transmitter near your work (GSM,...) and this transmitter congests your receiver with strong signal, the firing unit will not misfire, but will have troubles to find your weak signal in the air. In this case it's better choice the Yagi - directional aerial which sights to the transmitter. If you work in open space and want to increase the range only, the omnidirectional aerial is the better way.