MSR High Level Transmitter (HLT) Description (Ves Fulp)
The MSR transmitter was so massive physically and technically that it can't be described easily in a few words. These descriptions are extracts from a final document I was asked to write after the MSR site deactivation. It was used by some government organization (I believe it was GSA) to send out to other military, government, and civil organizations to see if any of them wanted any of the equipment. I want to point out that although I wrote these overviews for use by GSA, I used existing documents and publications created by Raytheon, Bell Telephone Labs and Western Electric.
A shorting gate would contact each bank of capacitors to ground the residual charge when the door to the high voltage room was opened or there was some other requirement to dissipate the stored charge.
The VA-144A high power klystrons used for the MSR were specially designed by Varian Associates. Due to the hybrid design incorporating a travelling wave tube (TWT), they were called twystrons.
Al LaRue, one of the principal designers at Varian, was on-site in North Dakota during installation and testing of the tubes.
Each of the two tubes cost approximately $750,000 (1970's dollars).
1069: Each of the two klystrons is mounted in a tank containing 3,500 gallons of high dielectric strength transformer oil. Comments
1070, 1074: Platform can be seen above each klystron tank.
All components needed to pulse the modulating anode were immersed in the oil tank.
The water cooled collector portion of the klystron was housed under the shield on the platform above the tank. This shield was commonly referred to as the klystron "hat."
Each shield weighed approximately 6,000 pounds was constructed of 3/4 inch lead with a 1/4 inch stainles steel liner to provide X-ray protection.
1074: The microwave balcony containing the high level wave guide switches (kludge) is in the upper left (above the fluorescent light).
Controlled the output RF power from each klystron. These outputs could be:
combined and fed to the antenna (the normal condition)
fed into high-power dummy loads (one or both klystrons).
If a single channel (klystron) malfunction occurred, the combining hybrid was automatically switched out and the remaining channel was connected directly to the antenna.
Water cooled, including waveguides and dummy loads.
Under software control, this bank of three high power RF switches connected the combined output of klystrons to one of the four antenna faces.
Although only one antenna face could radiate at a time, switching times were fast enough to make it appear that multiple faces were radiating simultaneously.
The large red buttons along the tops of the control panels were "Emergency OFF" buttons used to shutdown all low voltages and high voltages throughout the transmitter areas, including the firing of the "crowbars" to discharged the energy stored in the high voltage capacitors.
Contained equipment for the purification, filtering, circulation, and heat exchanging of the high purity water, dielectric oil, and dielectric gas (SF6) used by the transmitter.
During attempts to resolve a problem with the klystron cooling water flow, these were used as copper pellet scavengers to remove sulfides from the water.