My new dual channel antenna switch is up and running. Everything works as designed.

This week, I finished my dual channel antenna switch for diversity reception, as shown above. Previous posts have shown the concept and wiring. Channel A is dedicated to my East orthogonal loop from the wideband array. Channel B can be remotely switched to the West orthogonal loop, my main Ham antenna or the Wellbrook loop.

All switching is controlled over WIFI  with the NodeMCU relay board. A separate four input coaxial relay controls the Channel B antenna selection.

As mentioned previously, my main innovation was to forego complex coaxial switched for the two channels. Instead, I am using a pair of four output distribution amps into a patch bay to drive the RSPduo, Afedri, ANAN receivers and a DX Engineering NCC-1.

All the components are mounted on custom 3D printed structures, screwed into a piece of painted plywood.

I have tested the performance of these distribution amplifiers using a signal generator and spectrum analyzer, and all works as expected. These amps run off an internal battery or external five volt power.

Dual Channel Antenna Switch Control

For control on my shack computer, I have written a lightweight Windows application, shown upper left. All of the logic is contained in the program. I use a sixteen position Boolean array to set each relay on or off.

To update control, we simply send a text string representing the array states to the NodeMCU (like an Arduino) which controls the relays.

This has been a nice little project. I can now do diversity reception on dual channel receivers using a variety of different antennas and noise probes. As you can see, this new set-up is a bit more complex than the original design, but not overly so. It’s a great feeling when weeks of thinking leads to a final product!