How does a Baofeng radio know an incoming transmission is from a repeater?

Question

Baofeng radio's have two menu options for squelch tail elimination (STE). Item 35 is for general simplex STE, and item 36 is for repeater STE.

My question is how would the radio know if a transmission is coming from a repeater in order to apply the setting from #36 instead of the setting for #35?

Also menu 36 (RP-STE) has ten settings 1-10, is there an intuitive way to think about what this sensitivity means? At least whether value 1 or value 10 is the most aggressive squelch setting.

The simplex version (item 35, "STE") is just off or on, so I'm not sure how that maps to the 1-10 settings in the repeater version.

Answer 1

It doesn't know anything.

"STE" is the easier one to explain. It controls transmit, not receive. When STE is enabled, when you let go of the PTT button, the radio will send a 55Hz tone for a moment. Other Baofeng radios mute the receive when they hear a 55Hz tone... whether or not the STE option is enabled, whether or not you want it. It has no (useful) effect when the receiver is another type of radio, and if you use it with a repeater, the repeater won't recognize it, and the 55Hz tone won't get through the repeater's high-pass, so it does nothing at all. There's really no use turning this one on in a ham environment.

"RP-STE" is more mysterious, but what I'm gleaning from several sources including this poorly translated Midland manual and the RadioReference wiki is that it only stops you from hearing your own tails by muting the receive for a moment after you let go of PTT, and you adjust the timing to match how long the repeater holds the channel after it stops hearing input. This is a lousy idea (among other things it makes it harder to tell if you doubled with someone, and might cut off the beginning of a reply to something you said), so everyone recommends that this option is set to OFF as well.