When I first started my EME tests I was running the TS2000 barefoot and without an LNA so there was no need to worry about using a sequencer. This changed as soon as I installed the LNA. Even though it had RF-sensed switching and was supposed to be good for more than the power I was running, I did not feel comfortable working that way. I spent some time searching the Internet looking for something that would meet my requirements:
- Minimum of four switched events.
- Switch each event to either to ground or control 13.8V
- To be controlled by either a PC COM port for data modes or regular Microphone PTT for SSB use.
- Provide “TX inhibit” for rigs that support it.
- Simple design and construction using readily available parts.
Having looked at many different solutions I found that the W6PQL sequencer met my requirements the closest.
I built the sequencer on basic copper strip board and added four relays and “jumpers” so that for each event I could either switch the line to ground, provide 13.8V or in the case of the LNA switch the 13.8V supply off.
The LEDs were only in place during testing and were moved to the front panel when the circuit board was fitted into the box.
The three switches enable me to:
- Switch between Com port or Microphone PTT control.
- Switch the LNA on / off
- Bypass the PA and run the rig barefoot.
The four LED’s light as each event is enabled.
The Microphone sockets on the front and back panels allow me to “break” the PTT line to the TS2000 and use the controller to enable TX / RX. So now the standard microphone simply plugs into the squencer and a new 8-way (1:1) lead goes from the sequencer to the microphone socket on the front of the rig.
Like most of my projects the box remains un-painted…