SunnySkyguy ,I am retired now (14 years!), but its a fact that all analogue VHF and UHF TV transmitters have to use what we call AVRs ( Automatic Voltage Regulators) or it seems others call "stabilizers. This is because of the requirement to keep the HV +- .25% at a load of up to 250 kW. This is because the thermionic device has to be used over an extremely non linear part of its transfer characteristics so the video has to be pre-corrected for this non linearity.
Now the UK has gone digital, at least 400 AVRs have been dumped.
Do you still have analogue TV in the States?, if you do you will still find AVRs.
Frank