The spectrum of an IC706MKIIG when hand keyed with full
power at normal keying speed.
The serial number is 06230.
The peak power when the key is closed is 1.6 dB higher than
the continuous power.
The keying clicks are worst at a power setting of "4" which gives
a key-down power that is 4 dB below the key down power at the
maximum power setting "H".
The peak power at key closure is 4.2 dB above the continuous
power level which means that the power at the onset is slightly
higher than the continuous power at the maximum power setting "H".
Here the IC706MKIIG is operated with the power setting "H" but the
continuous wave power is reduced by 3 dB with a fixed voltage, -2.13V
on the ALC input.
When operated like this, the peak power at key down is 1.6 dB higher
than the continuous wave power because of voltage drop.
The images show that the ALC is not active much at full power on 144 MHz.
At reduced power levels it modulates the signal with ugly AM sidebands.
On 14 MHz and probably on all other HF bands the ALC is active also at
full power and a fixed voltage on the ALC input is probably the best
way to reduce the interference emissions.
Better solutions are of course possible if the unit is opened and