Paul, consider making a post on the SPARK page about some users of the Baofeng UV5R having very weak transmit audio, I’m sure you’ve noticed that. Most likely it’s because the UV5R is set to Narrow Band mode. Here’s how to check it and change it to Wide Band mode if needed.
1- Press MENU at the upper left corner of the keypad. Voice will say “MENU”. (hopefully in English!)
2- Press the Number 5 on the keypad. The display will show either NARR or WIDE.
3- If the display shows NARR, press MENU. Voice will say “CHANNEL BANDWIDTH”. (If the display shows WIDE merely press EXIT)
4- Press either the UP arrow or the DOWN arrow on the keypad, the display will then show WIDE.
5- Press MENU. Voice will say “CONFIRM”.
6- Press EXIT.
If this procedure doesn’t cure the low transmit audio the user should speak louder and make sure the microphone (behind that teeny tiny hole to the left of the speaker and above the A/B button) is directly in front of and close to the user’s mouth. Sometimes during assembly the piece of foam that holds the microphone element in place gets dislodged and may partially cover the microphone element, that usually requires disassembly. Sometimes that teeny tiny hole needs to be reamed out ever so slightly. Don’t go very deep or the the microphone element will be destroyed, and a speaker mike is the only recourse from then on.