Oh, it was very good times long ago. I
had one antenna on the roof and one home-made transceiver in the
shack. My antenna was connected to transmitter without even using
an RF-connector. Coaxial cable from the antenna just was soldered
to transmitter's PA. These are the times that every radio amateur
remembers as being the best in one's radio amateur life.
But in due course, new antennas were installed,
to first home made transceiver was added a commercial made second
one then an old military third... Antenna connectors on these
transceivers were differed from each other. That situation caused
to use RF adapters and special coaxial cables to alter the arrangement
of rigs and antennas.
There came a time when I entangled in antennas,
receivers, transceivers, and the methods of switching to alternate
antennas and change from one rig to another.
Solution was clear- it should be used clear
marked an Antenna Switching Unit (ASU).
So to make life easy I made several experimental
Antenna Switching Units that some of them are described below.
A schematic diagram for universal ASU is
shown in Figure 1. The
unit provides connection of 3 transceivers and two receivers (or
transceivers) to one of four antennas or to a dummy load 50 or
75 Ohm (in the USSR some commercial made transmitters have 75-
Ohm output). It is useful to connect a small bulb in series with
the dummy load that allows estimate power level of the used transceiver.