🔍 Key Concepts

• Keying in radiotelegraph transmitters – what it actually means in the circuit • Differences between RF (radio frequency) stages and power supply/filament circuits • Impact of keying different points on clicks, chirp, and stability of the transmitted signal

💭 Think About

• Think about what the telegraph key is really doing electrically: is it turning RF on and off, changing bias, or interrupting DC power? • Consider which parts of the transmitter you can safely switch on and off without causing big voltage spikes or instability. • Ask yourself: where in the circuit does keying most directly control the RF output without excessively stressing components?

✅ Before You Answer

• Clarify for yourself whether keying the control grid is a common and practical method in classic CW transmitters. • Decide if keying the main DC supply to the transmitter stages is technically feasible and historically used. • Verify whether primary of the power transformer, filament center-tap, and screen grid circuits are also realistic places where keying has been implemented.