On Sunday 6/12/22, I was checking out the station ahead of our club’s upcoming Field Day. Running through the stacks on Tower #1, I encountered troubling readings on the 20 meter stack.
SWR on each of the three measured independently was fine; however any combination of 2 or 3 antennas sent the SWR to >6:1.
On Tuesday 6/14, I went to the cabinet at the base of the tower. I disconnected the feed lines to the three antenna from the Array Solutions Stack Match. Measuring each antenna with my Rig Expert AA-55 Zoom, I discovered that everything up the tower checked out in 100% working order.
Since I had several new Stack Match relay boxes on the shelf, I simply replaced the relay box.
Back in the shack, everything checks out!
I’ll troubleshoot the bad relay box another day!