A stack match is used so the user can have two antennas connected at the same time.
what good is that ? it allows you to have one antenna higher than an other. giving you two different arrival angles at the antenna. arrival angles change throughout the day and time of year.
So what good is a stack match ?
As already said, It allows the user to have two antennas at the same time or switch between the two to hear which antenna is hearing the wanted signal better.
My design was drawn on a peace of paper at work.
for the transformer I used a single FT240-31 toroid. I used #12 enamelled wire paired and six turns through the toroid. this was my start point.
I then laid out components to see which way would best fit the aluminium boxes I had.
Then I started to make the switch to select both or either antenna. this was a simple rotary switch with 12vdc. connections were made with CAT5 cable with ferrites either end.
LED's to show UPPER, LOWER or BOTH antenna selection.
All boxed and ready for testing.
I first connected an antenna and a dummy load to the outputs. I then checked to make sure the switching was working.
then using my antenna analyser, switching both or either antenna in and out. across 21MHZ VSWR was no worse than 1:5.1
I have tested with same set up but with radio and amplifier. analyser doesn't lie.
designed by me, loosely, built by me and tested.