Amateur Radio Island - Our "antique" R-140 amplifier with GU43B tube, which had been working for many years, suddenly died. It will take a long time to get it repaired back to
FRI-1500 HF amplifier with GU-43B
GU-43B (GU43B,GU-43/B,GU-43A,GU43A) (similar to 4CX1000A) Russian Military tetrode
DC9DZ: Project Katana 3K – Power Amplifier (PA) using GU43b
YO3FBD - GU43B Amplifier Construction Stages - YouTube