Review: The Impossible Baofeng HTs. The Baofeng dual-band UV-82. Like set frequency steps not allowed by the original Baofeng programming software. Nov 08, 2014 UK Radio Scanning Forum. Unearth The Great Dividers Free Mp3 Download. An informed & evidence supported complaint being made about your piracy being made. Baofeng Bf-888s (x2) Boafeng UV-5B.

Baofeng Technology produces inexpensive amateur radios. All About Circuits purchased a radio to take apart and look inside.

About the Radio produces radios that are some of the least expensive on the market. For (at the time of publication), we bought a dual-band handheld transceiver (HT) that operates in the VHF and UHF amateur bands.

This is the type of radio that tends to end up in emergency kits or the car glove box for emergencies. Before you buy one, you should investigate licensing requirements in your country. Broadcasting on certain frequencies without the proper authorization is illegal in many places around the globe. Image courtesy of. The radios we took apart for this week's teardown are the UV-5R and the UV-5RB, though there appear to be many products by Baoefang with a similar product designation (UV-5R, UV-5RA, UV-5RB, UV-5RC, UV-5R+, UV-5R V2, etc.).

While only the UV-5RB will appear in the following article, the interior layout of the two radios is largely identical. I opened two radios because the UV-5RB that I initially tore down had multiple integrated circuits with illegible or completely absent top-side markings. Schematic courtesy of.

The schematic matches the components in the radio to a large degree. However, some slight discrepancies between the schematic and the circuit board I had in front of me lead me to believe this schematic is for a design variant. The duplex transceiver and separate FM receiver on this circuit board can be controlled with I²C, so it should come as no surprise that there are people out there who have the device and programmed their own microcontrollers. Again, I'll again caution you to read and understand the laws surrounding broadcast in your jurisdiction. You must be licensed to operate a radio that transmits on certain frequencies and fines in the US are in the five-figure range. Tearing Down the Radio Begin the teardown by removing the battery and the belt-clip.

Pull the volume on/off knob off of the potentiometer and unscrew the antenna. The potentiometer and antenna are secured to the case with threaded retaining rings (spanner nuts). The can be unthreaded with a flathead screwdriver, forceps, or perhaps a retaining ring plier. Remove the four visible thermoplastic screws with a T-8 head. Then remove the small piece at the top of the radio that held the belt-clip. The circuit board and metal backplate can be gently pried up and out from the front of the case and removed. Finally, the circuit board can be removed from the metal backing after several Phillips head screws are removed.

See the video below for more details. Top-Side Marking Description More Information None EM78P568 Microcontroller BL24C64 I²C EEPROM BF-B 1223 AT1846S Single-Chip Transceiver RDA 5802N Single-Chip Broadcast FM Radio Tuner LM358L Dual Operational Amplifeer TDA2822 Low Voltage Power Amplifer None Hitachi HD44780 LCD Controller / Driver The digital circuits on the board (2, 3, 4, 5, 8) are controlled primarily through I²C by the microcontroller (1). Two analog amplifiers (6, 7) amplify the audio from the onboard microphone (6) and the external microphone/speaker connectors (7). Front and reverse circuit board sides with integrated circuits of interest outlined and numbered (1) EM78P568 Microcontroller (Red) This microcontroller is powered by a low-power, high-speed 8-bit RISC microprocessor with 26 Kilobytes of one-time programmable (OTP) read only memory. EM78P568 block diagram. Image courtesy of It also features tone generators capable of generating Continuous Tone Coded Squelch System (CTCSS) and Dual Tone Modulated Frequency (DTMF), as well as detectors for both. These can be used as a means of access control to a repeater—a radio that broadcasts the CTCSS tone will have its message relayed, while a radio that doesn't broadcast the tone will not. Alternatively, it can be used to enable reception on a particular receiver without disturbing other listeners on the channel.

Imagine having a dozen users on the same channel and the ability to transmit to an individual user, subgroup, or the entire userbase. (2) BL24C64 (Orange) 24C64 block diagram. Image courtesy of This is an I²C Electrically Erasable Programmable Read Only Memory (EEPROM) that supports a maximum clock frequency of 400 kHz. There are three inputs on the IC that allow eight different addresses on the same line.

Data is organized in eight 8192 bit blocks. (3) BF-B 1223 (Yellow) I was not able to positively identify this integrated circuit.

There is a possibility that it is the 8-pin Text-to-Speech (TTS) IC shown in the schematic. In the second radio I opened, the IC in the same spot was labeled 'LT-ZY606'. I have never seen an 8-pin TTS IC, and wouldn't have suspected it to be the TTS IC except for the 8-pin IC in the schematic labeled 'Voice.'