Thursday, March 8, 2012

Baofeng UV-3R: Extreme Modding

I'm not sure if I should compare this to working with Legos, AR building, or customizing a Fast & Furious type Japanese sports car, but RDS_6 went all out with his mods on the UV-3R:

1. Added 47pF missing capacitor to VHF LPF. Improved VHF 2nd harmonic
suppression by 12dB.
2. Added 0.001uF (i.e., 1nF) capacitor from PTT line to ground. Solved PTT
lock-up problem with external mic.
3. Changed R13 in path from RDA1486 transceiver chip to LM4890 AF amp chip from
10K to 33K. To reduce RX audio volume.
4. Changed R10 in path from pin 27 of MC81F8616L MCU to LM4890 AF amp chip from
100K to 1M. To reduce beep volume.
5. Added 1mm thick pad of non-woven polyester fibers between internal mic rubber
boot and front housing. To reduce mic sensitivity and to reduce wind noise.
6. Added 15K chip resistor across internal electret mic element. To reduce
internal mic sensitivity and prevent RDA1486 transceiver chip from overdriving
and limiting/distorting TX audio.
7. Built quarter-wave (i.e., 19.5 inch (495mm)) antenna from 20-gauge (0.032")
music wire. To replace unimpressive dual-band antenna that came with the radio
when I bought it used.
8. Added quarter-wave (i.e., 19.5 inch (495mm)) counterpoise of 22-gauge
stranded wire. To further improve antenna.
9. Bought Body Glove universal cell phone pouch 170-5997 (CRC91777) for $2.97
clearance price at Radio Shack. To protect and carry radio.
10. Punched holes in the cell phone pouch for internal microphone and speaker.
To be able to use radio with internal mic and speaker while in pouch.
11. Bought UltraLast UL-NP60 (230-0485) 1100mAH lithium-ion batteries for $1.97
clearance price at Radio Shack. To have extra batteries at almost no cost.
12. Used only the radio's internal charging circuit, not the external tray
charger, to charge the batteries. To ensure the radio's LTC4054 lithium-ion
battery charge controller chip is managing battery charging.


  1. my local dollar store carries yellow, red, and blue neoprene cellphone pouches w/a belt clip for, yep, one buck each - i bought a yellow and red one for my red and yellow UV3rs


  2. Here is Extreme Modding UV-3R: