I keep hearing about staying away from "band edges" but I'm not sure I understand why. If the FCC says 14.000-14.350 MHz is the 20m band, why can't I use 14.000 exactly? What's the technical reason behind this advice?

Looking for a clear explanation of:

• What causes frequency drift
• How sidebands work
• Practical operating guidelines

Some radios, especially if they're not warmed up, might drift slightly in frequency as you operate. Plus your voice sidebands extend beyond your carrier frequency, so operating exactly on the edge could put part of your signal out-of-band.

Think of it this way - if you're transmitting SSB at exactly 14.350 MHz, your upper sideband extends above that into the non-amateur spectrum. It's good practice to stay a little bit inside the band edges when you transmit, giving yourself a safety margin. Most experienced hams try to stay at least a few kHz inside the band.

From a contesting perspective, we're very careful about band edges because operating right at the edge of a band or sub-band is like walking a tightrope over a pool of regulatory sharks - one small misstep and you could find yourself in dangerous waters. Better safe than sorry when there's an FCC notice at stake!