The Megawatt Myth

Radar manufacturers who market “megawatt” radar systems sometime fail to tell the whole story. Let’s first look at the radar cabinet located on the ground that houses the transmitter. Some magnetron and Klystron transmitters do produce 1M watts of power but this power must then pass through a band-pass filter and then a haromonic filter causing significant loss. The power leaving the cabinet is now around 560,000 watts. Then add a typical 100-ft wave guide run to the antenna and the output power is further reduced. It is now about 445,000 watts – not 1,000,000.

The Dual-Polarization Megawatt Myth

The loss is even worse in a dual-polarization system that has only one transmitter. Some dual-pol radar manufacturers use only one transmitter not two in their dual-pol systems. They add a power splitter on the antenna to make the Horizontal and Vertical channels to create dual-polarization. The power splitter further reduces the output power by an additional 50%. Ouput power at the antenna feed is now less than 225,000 watts – less than a 1950’s 250 Kw radar. The use of these power splitters is a very inexpensive way to make a dual-polarization radar but the result is significant limitations to system functionality and product generation.

Illustration of power loss in a typical megawatt system:

 

megawatt illustration

Weather Detection Systems, Inc.  |  Evergreen, CO  |  303-679-3167 T  |  720-837-9468 M