A Triplexer... What is that?

Three Transmitters, One Antenna or Vice-Versa

You have probably heard about triplexers but are not sure what are they. Here is a simple explanation.

A triplexer is a device that allows 3 transmitters to share one antenna. The transmitters have to be on different frequency bands and the antenna needs to tune 3 bands. A good example is during a contest: 3 operators working with 3 transmitters one on 20m, second on 15 meters and third on 10 meters and the antenna is a 3 band Yagi 20-15-15 meters.
Inside a triplexer are filters that prevent power from one transmitter being routed to second transmitter and so on. 

A triplexer can also work backwards – it enables use of 3 different antennas with one radio. Here is an example:

A triplexer might not have enough attenuation to prevent strong signal from other transmitters from entering the receiver input. This could damage the receiver’s front end. Therefore extra filters are used:

More on this topic in the next Communicator... here December 1st

~ Les Tocko VA7OM