You don't need 10 Hz low end response, thats wasted power since most receiver/speakers won't >reproduce that. Also, the capacitor is just another source of stored energy in your radio, to deal >with from a safety standpoint. More is not always better.
But to avoid excessive phase shift distortion, the uniform frequency response should extend at least one octave above and one octave below the intended range of frequencies of the modulation.
Therefore if, for example, your target is to actually transmit audio ranging from 100~ to 5000~, the speech amplifier/modulator should be essentially flat from 50 to 10,000~. Even "communications quality audio" response of 300~ to 3000 would require at minimum a uniform response in the audio section of the transmitter of 150~ to 6000~.
UTC ran this recommendation in their LS- series transformer catalogue, and I seem to recall seeing it in Thordarson's Tru-Fidelity catalogue also.
Don k4kyv
