On Uniden scanners, the headphone jack is a stereo jack with the same audio going to left and right channels so that both sides of headphones or earbuds will have sound. Avoid using a mono plug in the headphone jack as that will short out half of the audio output amp and possibly cause damage to your scanner.
Also, the headphone jack volume level is purposely reduced for ear safety. If you have to connect an external speaker with a mono plug to the earphone jack, use a stereo to mono adapter at the jack, and using an amplified external speaker would give you much better volume output at the speaker.
On Uniden scanners with an ext speaker jack, that output Is a mono jack, and at normal audio volume levels…. A much better choice for an external speaker.
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