Baofeng UV-5 DIY Microphone

[Buick Mackane]

Cobbled this together with parts from my junkbox. The casing is an old noise cancelling mic. The lead is from an old pair of headphones. A condenser mic i had laid about and a few jack plugs. Its not a speaker mic. I have added a 3.5mm socket to plug in an extension speaker. As it will only be used for homebase use.

I could have bought a speaker mic for a fiver. But i enjoy making stuff and already had the parts..How does it sound ? Not tried it on air yet. Probably like I'm upside down in a wheelie bin full of water

[NightProwler]

I like your fluffy rug

[rob42]

I have a question that's related to this, if anyone can help, please.

First, the issue: I'm sure that a lot of you will be aware of the weak modulation that these little Baofengs suffer with. I've been running some test transmissions, which have suffered with this issue.

The fix? I have an external mic/speaker combo on order (I don't yet have a collection of gear from which I could build one) which I hope will be no worse, even if it's no better. So, would it be okay, do you think, to put a adjustable preamp in circuit? I thinking that the external mic/speaker could be plugged into a custom made preamp black box, in which the two circuits could break out. That way both the mic signal and the speaker signal could be redirected; the speaker return to a better speaker that could be housed in the black box, maybe even run through its own amp for tone and bass processing (clearly, the box would need a hole in the side that's as larger as the speaker cone) and the mic signal run into the preamp before going to the Baofeng.

I have read the suggestion that enlarging the small mic hole in the body of the HT may help, but I don't like modding gear in a way that can't be undone, plus I'm not convinced that it would make a whole lot of difference.

Your thoughts and / or suggestions are welcome.

[Antoni]

The mic gain on the Baofengs et al is sufficient. The bigger hole really does work!

At Lowe, we chose a good product from Taiwan for a police force to use on their radios, they liked it. But... they said the transmit audio was poor. I checked them closely and they were, particularly in the higher audio frequency range.
The solution was to take a box of abt 250 units, fit a No.5 pointed tip to a Weller (500F temperature) and carefully poke it into the mic hole. The result (after practicing) was a clean and larger mic-hole. The audio was much improved. I asked the factory to change production and they did. I could tell you a similar story abt the bloody awful Maruhama 618 scanner.

Why all this hassle? Why is it continuing to this day?

Think abt the polish language - the old joke where a Pole went to the optician who asked him "can you read the bottom line?" "Read it? I know him!" was his reply. Fact is some languages use a lot of consonants. My favourite word is Skrzyżowania which is the word for a crossroads. [ https://forvo.com/word/skrzy%C5%BCowanie/ ] Imagine that with no high frequency in the audio path.

In China and Taiwan there just aren't as many S Z X Ch Sh sounds and so they don't notice the problem when they test their kit.

Some DSP codecs address this difference in languages.

Get in there and modify your mic!

[Buick Mackane]

The receive audio doesn't require any processing, Its fine when fed to an external speaker, As for TX audio being weak Ive never had any complaints, But i rarely use the radio, As pointed out above sometimes the tiny pin hole in the mic casing needs widening..Be careful messing about with pre-amps,Too much drive and pop goes the weasel

[rob42]

@Antoni. You make some very interesting points that I would have not thought of. Thank you very much.

Possibly, I'll try and open up the Mic Hole. As I said, I do have this hand-held Mic/Speaker combo on order, so I'll see how that turns out first.

I think that the fact that I don't like to have the HT close to my head, is adding to the issue, hence the need for the said add-on.

@Buick. Thank you for the advice. I have this wiring schematic. Does it look correct, to your eye?

a2658c0b9e854ad2286a0d15670c879b.jpg

QST: Digging around, I have come across this Vivanco unit. Maybe a good base from which to start?

side_shot.jpg

top_shot.jpg

I will also put my meters to work and discover what signals I have, compared to what signals I'm likely to generate, as a before and after kind of test.

[Buick Mackane]

Yes same schematic I used. Bare in mind one plug is a standard 3.5mm the other is 2.5mm

[rob42]

Get in there and modify your mic!

Inspired be these words, I decided to apply bravery and caution, in equal amounts, grab a No2 drill bit, and have at it!

I also loosened the back of the unit and remove the locking rings on the top, so that I could create some wiggle room between the PCB (onto which the Mic is surface mounted, would be my guess) and the upper body.

mic_hole.jpg

Up close, it looks a little rough, but other than that, I'm going to call it done. I'll wait for peeps to be doing other stuff before I go and test the results; not there's too much RT in my area, but if I'm kind of under the radar, there's no real chance that I'll upset anyone.

Now, I'll wait and see what else (if anything) comes back. If needs be, I'll start another thread, rather than continue with my hijacking of this one.