i he compact SBE SB2-LA linear amplifier operates at 1000 watts PEP input on 80 through 20 meters and 750 watts PEP on 15 meters. Although the SB2-LA was designed as a companion unit to the SBE 34 transceiver, it will boost the output of any SSB transceiver up to a full kW PEP.
The input circuit of the SB2-LA uses a passive grid input circuit which offers a pure resistive load to the exciter. In the output a pi network provides matching to the transmission line with band switching from the front panel.
The built-in 115 volt ac supply is a voltage multiplying type unit; the high capaci tance filter capacitors provide excellent dynamic regulation. The low plate voltage— 800 volts—is used with a relatively high current level. This arrangement is easier on the capacitors* recti fie rs, power transformer and six parallel connected 6JE6's used in the final.
The SB2-LA has two built-in antenna changeover relays and internal blocking bias to prevent diode noise when receiving. For mobile operation the SB3-DCP inverter is available for powering the SB2-LA from a 12 volt source. The output of the inverter is 120 volts ac at 1200 watts; in mobile service the internal ac power supply is used.
Swan Mark 1
The new Swan Mark 1 linear amplifier uses two 3-400Z or 8163 zero bias triodes in a grounded grid circuit for convcrvative maximum legal input rating, A built-in power switch reduces the input to 1000 watts dc for CW and tune-up. The untuned input circuit provides the maximum in operating ease and permits very fast and wide range frequency changing.
The built-in 2500 volt solid state power supply may be powered from either 115 or 230 volts ac. It is very conservatively rated and the use of semiconductor recti-
fiers provides extended trouble-free operation- I'he tube cooling concept used by the Swan engineers guarantees long tube life and reduces initial equipment cost.
Dual change-over relays automatically switch the exciter in and out of the transmission line. The wide range pi-output network allows the Mark 1 linear to be used with a variety of antenna systems without the necessity of external matching networks. The metering of grid current, plate current, plate voltage and relative rf output permits monitoring of all the essentia! parameters and maximum tune-up ease,
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