So I received a high power RF amplifier from a guy who repaired it for me. Long story short, the guy said he also did some "tuning" to give more output at my desired frequency. Anyway, when I received the amp, it just had what looked like an inductor soldered on the output, but the other end was not connected to anything. The "inductor" was made from coax with both ground and center RF wire connected, but nothing connected on the other end. Can anyone explain to me what this is or if the guy is pranking me to see if I would notice?