Setup guide

The schematic above represents a partial schematic (only antennas 1 and 2) and not that the "Inhibit"
connections are to "Key In" on the PA port.
The intent is to avoid using B7−B10 and to lockout transmit only on the 'second' radio. Remember
only the application software can prevent selecting an already used antenna port − this simply
prevents transmitting into an open feedline.
Using the situation of triband antennas on ports 1 and 2, the above circuit will prevent transmitting into
an open port. There is nothing that will prevent one
radio from selecting a port that is already in use by the other radio. The diagram above will prevent
transmitting with no antenna connected.
The transmit lockout uses an idea from Jozef (solution 1 above) (the Inhibit or Key In line) but uses a
pair of external 12V DPDT relays to do the switching ... in this case, if one radio has selected a port
that is "in use" it will be inhibited but it will not prevent the original radio from transmitting (e.g., run
radio is on 20 meters using the tribander and the S&P radio selects the tribander on 15 meters the run
radio continues to work because it was the first one there). This is a "first one wins" lockout. There is
no need for a "double" lockout − that is handled automatically by MK2R if both radios are put on the
13−2−20092 SO2R Setup at PA1M − microHAM MK2R+ and Station Masters and N1MM logger 17