Just upgraded to General and starting to explore HF bands. I keep hearing about staying away from band edges but I'm confused about the technical reasons. What exactly happens if I transmit too close to the edge? Are there specific frequencies I should completely avoid as a new General class operator?

Also, I notice my radio shows different frequencies for LSB vs USB - how do I calculate where my actual signal lands? Any practical tips for staying legal while making the most of our allocations would be appreciated!

You should not set your transmit frequency exactly at the edge of an amateur band to allow for calibration error in the transmitter frequency display and so that modulation sidebands do not extend beyond the band edge. On USB modes like 15m phone, you can operate down to about 21.200 MHz, but on LSB like 40m you'd use around 7.127 MHz as your practical limit. Remember - your radio shows carrier frequency, but your actual signal extends up or down from there depending on the mode.

The frequency shown on your radio is actually the carrier frequency, and for SSB the sideband signal can extend another 2.5 to 6 kHz up or down depending on whether you're using USB or LSB. Not all transmitters are calibrated perfectly, and some may drift off frequency during transmission due to temperature changes as the radio warms up. Always leave some margin!

Great question! The ARRL has detailed band plans for US hams showing allocations within each band. I'd recommend downloading their frequency chart and keeping it handy. As you get comfortable with HF, you'll develop a feel for where different activities cluster - CW down low, phone in the middle, digital modes in their designated segments. The band edges become second nature after a while.