Cosy MUTO, JH5ESM
This is an experimental results of 7MHz Class-C SEPP power amplifier using audio complementary pair 2SC2120/2SA950, held in 1991.
Both devices are for audio output stage of 1[W] output power, which have maximum rate of 600[mW] PC, 0.8[A] IC and 120[MHz] fT. The results has been reflected to my homebrew rigs such as 7T9521 “Komukai40” and obsoleted 7MHz DC transceiver.
The circuit under test was designed by the following procedure;
Schematic of the circuit under test (CUT), input vs output response and harmonic response are shown in Fig.1 through 3.
Maximum power gain and collector efficiency at 1[W] output are 12[dB] and 60[%], respectively, and these values are suitable for 7MHz QRP transmitters.
Even order harmonics are well suppressed as same as most push-pull amplifier does.