ok so i just upgraded to general last month and im trying to figure out where i can actually transmit on 40 meters. i know theres the tech portion and the extra portion and stuff but every chart i find online looks slightly different and some say the phone portion starts at 7.175 and some say 7.200 and i dont know which one is current. also whats the deal with band edges, my elmer keeps telling me to stay away from them but he didnt really explain why, just said it was bad practice. is it just an interference thing or is there a technical reason. sorry if this is a dumb question im still figuring all this out

not a dumb question at all, this stuff confused me for a while too. so for 40m as a general you can do SSB phone from 7.175 up to 7.300 MHz, that changed back in 2007 when the FCC restructured the bands so some of the older charts floating around are just wrong. the tech limit doesnt really apply to 40m the same way it does on other bands.

as for band edges, your elmer is right to warn you. the thing is your transmitted signal isnt just sitting on one exact frequency, your SSB signal has bandwidth, maybe 2.5 to 3 kHz wide depending on your rig and how its set up. so if you park your dial right on 7.175 and youre running USB, part of your signal is technically spilling below your privileges into the extra-only segment. FCC doesnt care about a few Hz but its still bad form and could cause interference complaints. most people just stay at least 3 kHz inside any edge to be safe.

yeah what he said. also just download the ARRL band plan pdf, its like one page and way clearer than trying to piece it together from random websites. i wasted so much time trying to read those color coded charts before someone told me about that