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With the help of some folks here I did troubleshoot my AC-1 tube transmitter
(using a 6V6) and got it working somehow. Since I passed my code test and had my first QSO using the transmitter and boy was that exciting. But questions remain. I monitor the output signal on my scope and notice that right after key down the waveform contract just a bit and the tone changes pitch. I guess this is called chirp. I normally use B+ 200V. If I increase the voltage lets say to 300V this effect becomes much more pronounced. I still use an external bench supply capable of much higher currents and I don't think it is a power supply weakness. In fact putting a VOM on the supply line shows no sag in my supply voltage. How can I minimize this and especially keep it from becoming more severe at higher outputs. Also, the circuit diagram for the tranmitter did not state the coil diameter of the pi network. The pi network still has me scratching my head. Coils with slight variations in diameter give dramatically different results. Also changing the air cap with one of an identical range can have a vast effect, which surprised me. Is this the "real world components" versus the theory??? Uwe |
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