The Collins 180S-1 Antenna Tuner is awesome. This is a “Winged Emblem” model where a previous owner added a watt-meter, and he did a very good job. He also added switches so you can switch it as a pi or an L circuit, which is a great mood.
When it arrived, the front two ceramic standoffs of the roller inductor were broken. Obviously, the package had been dropped on the right front corner. I had to go buy an extra long Phillips head screwdriver to undo the cracked standoffs. It was tricky because the area was very tight – but I figured it out, and it turned out to be quite a bit of fun – a nice time on a rainy day.
Collins 180S-1 pi / L antenna tuner circuit. I do not have the mod with the power meter or the two switches in this circuit – but I will update once I study it more and really understand what the fellow did.