*** The Ampliphase Ancestry ***
KOH 630, Reno, Nevada, 5KW Homebrew, 1951
KOH was owned by McClatchy Broadcasting, who also owned KFBK in Sacramento, KBEE Modesto and KMJ Fresno. The May 1951 issue of "Electronics" magazine features an article, written by Norman D Webster, entitled "Economical 5KW Am Transmitter". It describes in great length the design of a homebrew 5KW outphased Tx at KOH in Reno.
Several references are made to an existing 50KW design at KFBK, at which "several years of operatng experience" proved the "feasibility of screwdriver tuning adjustments". The article included a complete schematic of the transmitter, which is reproduced below.
It is interesting to note that KFBK in Sacramento later installed a BTA-50H, approx 20 years after they built their own. That ampliphase is still in use today as a standby unit, having been replaced in the late 80's by the first Harris DX50 digital transmitter, serial number 1.