ANTENTOP- 01- 2010, # 012

Linear Power Amplifier on G811

S. Bunin, L. Yailenko

Credit Line: Spravochnic Radiolyubitelya Korotkovolnovika, - 2 Izdanie, Kiev : Tehnika, 1984.

(“Reference for Ham”)

The PA is designed for ham bands 160- 10- meters. It provides 200 Wtts CW/ 500 Wtts PEP SSB. Efficiency of the PA is 65- 70% in depend on used r\band. Figure 1 shows the schematic of the PA.

Four tubes G811 (switched in bridge, grounded grid) are used in the PA. Four tubes may dissipative 160- Watts on their plates, so, the PA can work continuously with 200- Wtts output. Input resistance of the PA is closed to 75- Ohm at 160- 10- meters.

TX: Grids of the tubes are connected to the ground by pedal S1, antenna through contacts of Relay K1 goes to PA output.

Inductors L1, L2, L3, L4 are wound on Russian Resistors MLT- 2 (for sizes see: http://www.antentop.org/009/tst009.htm). Each inductor contains 5 turns and coiled by wire in dia 0.62- mm (22- AWG).

Chokes L7 and L8 is commercial made from old military equipment. May be used any suitable chokes.

Figure 1 Schematic of the Four- G811 PA

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