This amplifier uses a GU-78B with a 1/2l anode line. This tube is capable of up to 4KW output at 144MHz, but tube life is short at that level. This particular PA is to be operated at about 750W out; the tube lasts a VERY long time at this lower level and is virtually free of intermodulation products. More information, diagrams, schematics, etc., will be added as they become available. I have not been able to translate the text which accompanies the original OK1BAF presentation at http://www.ok1baf.wz.cz/m/m.htm.

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Ua - 3100V not load Ua - 2500V Full load Ia - 1.5A Ia - 4A peak Ug1 - 72V Ig1 max - 10mA Ug2 - 315V Ufil - 27V (28V for EME) Ifil - 3.5-4A 60W in 4000W out for EME Cath. circuit swamping eliminates oscillation

Cathode circuit swamping network consists of 16 x 600W resistors and 8 x 300 pF capacitors. Two of the resistors is series with a capacitor appear in eight places around the socket (see picture, below, right).