ANTENTOP- 01- 2018 # 022

Antenna Switching Units

Figure 4 System Transceiver- ASU- ATU- RF-bridge

Unusual ASU

 In the far 80s at one of Russian transmitting centers I saw an unusual ASU that was made from usual electrical light switches. It was ceramic- based light switches intended for 220V AC main. Schematic of the device is shown in Figure 5. Independent two-position light switches were used in the design. The ASU worked with HF transmitters on frequencies 2-25 MHz, one of the transmitters had 5 KW of output power.

 Figure 6 shows the unusual ASU with connections to transmitters and antennas. With the help of light switches it is convenient to switch symmetrical antenna that fed through two-wire ladder line.

 ASU on a Roof

 ASU installed on a roof allows use one coaxial cable to feed several antennas. Antennas in this case switched on by RF relays. Sometimes it is possible to use high quality industrial or electro- technical relays instead of RF relays. Differs from the way how the control (switch on/off) on the relay exists there are two sophisticated types of the remote ASU

Figure 5 Unusual ASU

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