okay so I got my tech license about three weeks ago and ive been listening to the local 2m repeater a lot, trying to get a feel for how things work before I start transmitting. but I noticed that some people when they key up there's like a brief tone right before their voice comes in, and other times there's nothing. is that just squelch noise or is it actually something intentional? I asked my buddy who got me into this hobby and he kinda shrugged lol, he's mostly into HF and doesnt mess with repeaters much.

also completely separate question but related — how do you know if a repeater requires a tone to access it? I tried keying up on one last week and heard nothing back, not even the tail or anything. my radio is a baofeng uv-5r that I programmed with chirp. just trying to figure out what I'm doing wrong before I accidentally annoy someone.

what your hearing is called CTCSS — continuous tone coded squelch system, though most people just call it PL tone or sometimes just "the tone." it's a subaudible tone (you usually can't actually hear it, it's below the normal audio range) that the radio transmits along with your voice. the repeater only opens up if it hears the right tone, which keeps it from triggering on noise or interference from other signals. some radios do a quick audible chirp or beep when they first key up which is what you might be noticing, but the actual CTCSS tone itself you wouldn't really hear.

as for why the repeater didn't respond — yeah almost certainly it requires a PL tone to access and you either didn't have one programmed or had the wrong one. most repeater directories like repeaterbook dot com list the required tones. just look up your area, find the repeater's output frequency, and it'll tell you what tone to use. program that into the transmit side in chirp and you should be good. the baofeng can be a little quirky with how chirp handles tones so double check it actually saved right by going into the radio's menu after programming.

yeah I went through the exact same confusion when I started lol. one thing that helped me was just going to repeaterbook and searching my zip code — shows you all the local repeaters with their tones and everything. some repeaters are open and dont need a tone at all, others are closed or require one. and a few around here are linked to other systems so you'll sometimes hear people from like 200 miles away which is kind of wild the first time it happens.

oh and don't stress too much about accidentally being annoying, everybody starts somewhere and most folks on repeaters are pretty welcoming to new people as long as you're not, like, kerchunking the repeater over and over without identifying. just say your callsign when you key up and you'll be fine