Since the topic of Band Edge has come up. I am interested in what people think
the band edge is on SSB.
I believe the FCC provides some guidance in Part 97. They define the width of
an SSB signal I believe as 36dB down from the signal on the center frequency.
This allows a "clear signal" to be closer to the band edge and still be
sufficient. Rather than a "broad brush answer" of 3khz away. In fact, 3khz
away isn't far enough if you are splattering 10 - 15khz wide with signal energy
above -36db.
I am assuming that most countries don't define the band edge other than center
frequency given that you always hear Europe on frequencies like 7199.9, 3799.9
and 14349.9.
I personally use 0.5khz above on USB and 2.8khz below. I periodically get the
"you are out of band" quips from the khz cops that think 3.0 is written in Part
97 somewhere. Its not. -36db is. And 3khz comes from a "rounded up" answer
to how far away do you need to be to insure that the properly modulated SSB
signal is -36db down form the center frequency.
Ed N1UR
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