Baofeng UV-B6 disassembly & drilling for audio

Recent listeners to the Monday Night Net would have heard the trouble a few of us are having with audio on the Baofeng UV-B6 radios. TX audio is muffled, and in some cases, inaudible. There's a mod you can do which involves drilling the mic hole a bit bigger, usually done from the outside, and stopping when you get 'the fear.'

I wanted to know why audio was so rubbish, and drill the hole from the inside out, exactly where the mic was. So I took my radio apart.

What I found was pretty surprising, even though I knew from the £30 price tag, the build quality was questionable…

The mic hole on this radio (a pinhole on the grille, bottom left) doesn't actually come out in front of the mic. Instead, it's to the right and blocked by foam padding and metal. That means in effect, the mic on these radios is enclosed in plastic. No wonder it's muffled!

I used a drill press to drill my mic hole, from the centre of the mic outwards, and you can see from the photo where it came out. Audio was much clearer, compared to sounding underwater before.

So, if you own one of these, and you don't mind the risk of killing it, or if you're already thinking of drilling the existing hole, my advice is to take the time, open the case, and drill from the inside to get the placement right.

Disassembly (sic. voiding your 'warranty') is relatively easy. You need a T9 Torx bit for two screws, the rest can be done with your normal toolkit. You do need steady hands, because the board interconnect is fiddly and the wires are short — there's not much room inside this radio.

Bonus find: There's one trimmer on the main board of this radio, which I'm reliably informed is the frequency offset. You can adjust this if your radio is off frequency and you have a good frequency counter. Mine was fine, so I did what you should do, and left it well alone.

As always, YMMV, and don't blame me if you kill your radio. For me though, it was a good experiment, and improved my TX audio readability.

Did you notice I said readability and not level? Sadly, the volume of the audio only increased slightly. This is a quiet rig (about half the volume) compared to my Yaesus, and while this mod means you can yell clearly and directly into the mic, I'm afraid the UV-B6 is just a quiet radio with its stock mic.

That said, not bad for a £30 rig, and I still recommend it for beginners.

Discuss this mod on my original post from the Essex Ham forum.