One more comment for Sholto on conducting tests of the measured response of audio frequency vs. power output of the SSB transmitter.
The test must be conducted into a dummy load at power levels well below any ALC action, such as 1 watt. You must use a low impedance calibrated audio signal generator to do this type of testing, or all of your measurement results will be invalid! Your generator must have a source impedance of 600 ohms or less. Use of a computer soundcard as the signal generator and/or a ham radio audio interface, may cause tilt errors in your measurement. There are ways to use a computer soundcard, with an external audio low impedance amplifier driver, but this also must be calibrated. If a cheapo interface such as a Signalink or other interface with small audio transformers are part of your test system, all of your measurements will be invalid. Use of an oscilloscope to monitor the constant level of peak-to-peak audio voltage to the transmitter audio input provides verification of the generator source. An oscilloscope may also be used with a power attenuator (or dummy load -20dB tap) to measure the power output. 73 Bonnie KQ6XA
