Archive ID: F00207

FullBack Print Main ArchiveThumbnails

Full image size: 566 x 708  BW

1970   One of the final vacuum tubes for KGEI's 50kW transmitter. Note the water jacket and copper tubes that circulate water from the downstairs cooling system. These tubes cost around $1200 (probably around $5000 in 2005 dollars) each and were rated at about 3000 hours. However KGEI often got considerably more than 10,000 hours out them. There was also at the time a "cottage industry" in tube repair for this type due to their widespread use in radio.