(2) Separate masts. Use of separate masts for transmitters and
receivers at a station will reduce the transmitter-to-receiver
interference at that station. This isolation can be further improved
by using vertical polarization for one antenna and horizontal
The two-block plan is used for simple isolated systems (an
isolated system is one which does not cross or connect with any other
multichannel radio system). For example, a system may consist of two
terminals and three relays with the radio sets operating between
220.0 to 404.5 megahertz (figure 18).
Simple isolated system.