A pure sine wave into the mic of an ideal SSB transceiver would transmit a clean AIA CW signal. ?In the real world, that sine wave will be distorted, and the carrier not fully suppressed. ?But it does allow you to transmit real CW on any unmodified SSB transceiver
As anybody who has checked in here in the last few months is likely long tired of hearing, I'd prefer generating CW by unbalancing the modulator as per post 20933. ?The DC into the modulator can be easily shaped to avoid key clicks, and this is not a sensitive point in the rig to be adding an extra bit of stuff to. ?What's more, it could make debug of the transmitter easier than it would be if injecting RF further down. ?On the other hand, you could have more parts fail in the transmitter chain and still transmit on CW if you are injecting 7mhz down by the LPF.
Jerry, KE7ER
On Tue, Feb 21, 2017 at 01:21 pm, Todd K7TFC wrote:
Aside from attempts to use the BitX for what I would call "true CW," i.e., "A1A" mode in which the carrier is directly keyed (with or without shaping) and having a "necessary" bandwidth of only a few hundred Hertz, I'm interested in clarifying the use of what is sometimes (erroneously?) called "modulated" CW (MCW): using SSB modulation to simulate the audible CW tone (in true CW produced by tuning away from zero beat) by injecting a fixed tone into the audio input of an SSB exciter. Though the resulting transmission would sound like CW in an SSB receiver, it wouldn't be intelligible in a CW-only receiver, nor would it occupy a narrow bandwidth like true CW. Moreover, since it would be SSB modulated rather than A1A CW, its use would not be permissible in the CW-only portions of the amateur bands. Those portions are reserved only for the narrow bandwidth of true CW, and an SSB-generated CW-like signal would take up as much bandwidth as several closely-spaced true CW ones.
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