A IC-275E hand keyed with dots on 144 MHz. Some keying clicks are visible at the lower sideband. The serial number is 01744.


The time domain waveform for key-down. White is amplitude, red is frequency.


The time domain waveform for key-up. White is amplitude, red is frequency. Note that the frequency jumps down by nearly one division (2kHz) while the amplitude goes through a minimum. This explains the keying click at the lower sideband frequency (See CW as emitted by a SSB transmitter). The mechanism is unknown but the keying click is not strong enough to be a real problem.