DP-666 TEF6686 High Sensitivity Full Band Radio User Manual

1. Product Introduction

The DEEPELEC DP-666 is a high-sensitivity radio designed around NXP's high-performance automotive-grade TEF6686 chip. This DSP tuner offers excellent selectivity and ultra-high sensitivity across various bands, including FM, LW, MW, and SW. It incorporates advanced algorithms for signal processing, noise cancellation, and improved performance in challenging reception environments with multipath or adjacent frequency interference.

The DP-666 is built upon the open-source project TEF6686_ESP32 by PE5PVB. It supports a wide array of features beyond basic radio reception, such as comprehensive RDS (Radio Data System) data display, automatic and manual station scanning, squelch functionality, battery voltage display, customizable themes, multilingual support, and station presets.

The radio features a redesigned circuit board and a 2.8-inch IPS LCD color screen with resistive touch. It includes a numeric keypad for quick frequency input and is powered by a large-capacity 5000mAh battery for extended standby time. Please note that the firmware is continuously being improved, and new features will be introduced over time.

Figure 1: Front view of the DP-666 radio.

For advanced users interested in the open-source projects, you can find more information here:

• PE5PVB project: https://github.com/PE5PVB/TEF6686_ESP32
• DP-666 project: https://github.com/flyoob/TEF6686_ESP32

2. Specifications

• Radio Chip: NXP TEF6686HN/V102 (F8602)
• Main Control Chip: ESP32-WROOM-32U, Flash 4MB, Wi-Fi + Bluetooth dual-core module
• Display Technology: 2.8-inch 320x240 resolution, IPS full-viewing angle LCD with resistive touch
• Control Method: Default numeric keyboard input and knob tuning; supports third-party touch screen firmware.
• Antenna Interface: Full-band external antenna, standard SMA female connector.
• Speaker Output: TI audio amplifier chip TPA6211A1, driving 45x45mm large-size sound cavity speaker, power 4Ω/3W, lower output noise and less distortion.
• Headphone Output: AD headphone amplifier chip MAX97220, standard 3.5mm audio connector output. Independent dual amplifier design for speakers and headphones.
• Battery: 3.7V/5000mAh, 18.5Wh lithium battery (size 65x55x10mm).
• Current Consumption: Approximately 3.7V/350mA, providing about 15 hours of usage time.
• Communication Interface: Built-in CH340 USB to serial port chip, through TYPE-C.
• Dimensions (WxHxD): 142*30*80mm (excluding antenna connector and antenna)
• Body Weight: 300g

Frequency Range

Note: OIRT default stepping is 30kHz, FM stepping is 50/100/200kHz, default is 100kHz.

Note: DP-666 does not support the AIR band. The AIR band that appears in the firmware requires an external downconverter to listen to. The downconverter needs to be purchased separately.

Receiving Indicators

Figure 2: Various views of the DP-666 radio.

3. Setup

3.1. Charging Instructions

The DP-666 radio is charged via a TYPE-C port. A charging LED is located above the TYPE-C port. To charge, use a charging head with a voltage of 5V and a current of 1A or above. The maximum charging power is 5W, and fast charging is not supported. It is recommended to charge the device with the radio turned off.

• The charging LED turns red when charging.
• The charging LED turns green when fully charged.

3.2. Initial Power On

Locate the main switch on the unit. The OFF position disconnects the battery, and the ON position connects the battery. For long-term storage or when not in use, ensure the main switch is in the OFF position to prevent accidental power-on.

After ensuring the main switch is ON, press the red POWER button. A short press will toggle the unit between on and off states.

3.3. Antenna Connection

The radio uses an external telescopic antenna with a standard SMA female connector. Attach the provided telescopic antenna to the SMA connector on the radio. For improved reception, especially for DXing, an external antenna can be used.

4. Operating Instructions

4.1. Basic Controls

• Main Switch: Located on the side/back, disconnects/connects battery.
• POWER Button: Short press to toggle power on/off.
• TUNING Knob (Rotary): Rotate to adjust frequency. Short press to switch tuning steps. Long press to lock/unlock tuning.
• VOLUME Knob: Adjusts audio volume.
• SQL Gear: Adjusts squelch level (refer to menu description for details).
• BW (Bandwidth) Button:
  • FM Mode: Short press to switch between Stereo/Mono.
  • AM Mode: Short press to switch bandwidth (3/4/6/8kHz).
  • Long press: Opens the shortcut page. Short press to exit.
• MODE Button:
  • Short press: Cycles through MAN (Manual frequency tuning), AUTO (Automatic search), MEM (Store operation).
  • Long press: Opens the main menu page. Short press to exit.
• BAND Button:
  • Short press: Cycles through bands (LW/MW/SW/FML(OIRT)/FM).
  • Long press: Opens the screen keypad page. Short press to exit.
• Numeric Keypad (0-9): Input frequency values directly.
• DX Button: Quickly save or delete the entered value. Long press to start scan.
• Enter Key: Toggle step or confirm input.

4.2. Main Interface and Icon Meanings

Figure 3: Main display interface.

Icon	Meaning	Touch Operation
	Frequency deviation status display	Enter or exit still screen mode
	Current stereo mode indication (2 circles for stereo, 1 for mono)	Stereo/mono mode switch
	Mute status indicator (highlighted means muted)	Enter or exit mute mode
	RDS icon (bright indicates successful demodulation)	Enter or exit the advanced RDS view
	Current demodulation bandwidth indication	Demodulation bandwidth switch (select AUTO BW if unsure)
	Wi-Fi status indication (function under development)
	Battery voltage/charge percentage indicator (voltage detection unavailable after Wi-Fi on)	Enter or exit screensaver mode

4.3. How to Store a Station

1. Tune to the desired station.
2. Toggle the MODE button until "MEM" is highlighted on the display.
3. Press the TUNING Knob button; "MEM" will turn red.
4. Select the desired memory channel using the TUNING knob or numeric keypad. Red numbers indicate stored frequencies, green numbers indicate empty slots.
5. Press the TUNING Knob button again to store the preset.

4.4. Menu Description (Advanced Settings)

Long press the MODE button to open the menu page. Short press MODE to exit. Use the TUNING knob to navigate and short press to confirm. You can also tap directly on the screen options.

Figure 4: Main Menu Screen.

• Main Settings: Configure model selector (Portable touch, Base, Portable), FM/AM band settings, screensaver time/options, system usage mode (Simple/Advanced), first page display, power off timer, dynamic SPI speed, still screen timer, and power off key.
• Audio Settings: Adjust internal DAC volume, beep at band edge, audio output (Stereo, MPX), stereo threshold, high cut corner/threshold, FM deemphasis, and squelch usage.
• Display Settings: Set language (English, Simplified Chinese), contrast, signal meter display/unit, signal refresh interval, battery options (voltage/percentage), modulation meter, themes, frequency font, screen flip/invert, UI style, color bar mode, and clock display.
• RDS Settings: Configure RDS underscore, filter, PI errors, AF usage, RT buffering, auto sort AF, fast PS, RDS clock, long PS, and disable all RDS.
• FM Settings: Set converter offset, low/high band edge, level offset, low level threshold, softmute, noise blanker, default step size, AGC, FMSI stereo improve, and FML band.
• AM Settings: Configure soft mute, noise blanker, RF level offset, SW wavelength display, CoChannel Detector sensitivity/counter, AM ATT, AM AGC, MW default step size, AIR band conversion, and AIR start frequency.
• Connectivity: Set USB mode (XDRGTK, RDS Spy), Wi-Fi active/configure, stationlist client IP/ID, screen off on XDRGTK, and Wi-Fi auto disconnect. Bluetooth active/inactive.
• Frequency Scanning: Initiate DX scanning, set scanning band, channel range, wait time, scanning method, auto cancel mode, cancel scan mode, mute while scanning, and screen off while scan.
• Auto Search: Start auto search, set search & save mode (Overwrite, Append), search band, FM/AM sampling times/hold, FM multipath limit, FM/AM scan sensitivity, judgement mode, save bandwidth, and mute while search.
• Operation Settings: Adjust menu display style, quick switch menu, touch type/calibration/interval, rotary usage (Classic, New), rotary adjust squelch, screen off rotating, reverse rotary, variable rotary speed, and long press key functions.
• Other Settings: Set date, time, local time zone, NTP/RDS time sync, and delete RDS dictionary.
• My Settings: Edit/use ATS scheme, edit/use scan scheme, set favorite theme, edit/use receive plan, and set shortcut icons.

4.5. Video Demonstration

5. Maintenance

5.1. General Care

• Keep the radio dry and away from extreme temperatures.
• Clean the exterior with a soft, dry cloth. Avoid using harsh chemicals or abrasive cleaners.
• Protect the screen from scratches.

5.2. Battery Care

• Charge the battery regularly, even if the radio is not in frequent use, to maintain battery health.
• Avoid fully discharging the battery for extended periods.

5.3. Firmware Upgrade

The firmware for the DP-666 radio can be upgraded via the TYPE-C port. Follow these steps:

1. Use the included USB-A to TYPE-C data cable to connect the radio to your computer. A new COM port should appear in your computer's device manager.
2. Press and hold the ESP32 BOOT button (located near the Type-C port), then turn on the radio to enter upgrade mode.
3. For firmware downloads and detailed instructions, please visit: https://deepelec.com/dp-666

6. Troubleshooting

• No Touch Operation: The current firmware does not yet fully support touch operation. The resistive touch screen is present, but functionality is under development.
• Wi-Fi/Bluetooth Not Fully Functional: The Wi-Fi function is still being improved, and Bluetooth functionality is not yet implemented. Programmers can explore secondary development.
• Increased Noise on MW/SW with Touch: When your hand approaches the touch display, it may increase background noise in MW and SW bands. Avoid touching the screen during sensitive listening.
• No Airband Reception: The DP-666 does not natively support the AIR band. To listen to the AIR band, an external downconverter must be purchased separately.
• No Arabic Language Support: The radio currently supports English and Simplified Chinese. Arabic language support is not available.
• SSB Reception: The product specifications list AM/FM, MW, SW, LW bands. There is no explicit mention of SSB (Single Sideband) reception support.
• Class D Amplifier Noise: Some users note that Class D amplifiers can produce noise at frequencies above 500kHz. While this is a characteristic of the amplifier type, the radio is designed for high sensitivity.

7. User Tips

• Excellent Sensitivity: The TEF668x tuner is highly sensitive, making it suitable for DXing (long-distance reception) even in urban environments.
• External Antenna: For optimal reception, especially on shortwave, consider using a high-quality external antenna.
• Customization: The radio is highly customizable through its extensive menu settings, allowing users to fine-tune various parameters to their preference.
• Beginner-Friendly DXing: This radio is recommended for beginner DXers due to its performance and features.
• Firmware Updates: As the firmware is actively developed, regularly check the official website (https://deepelec.com/dp-666) for updates to access new features and improvements.
• Audio Quality: While overall reception is superb, some users note that audio quality could be improved. Experiment with different audio settings and external headphones for best results.

8. Packing List

The following items are included in the product package:

• Host (DP-666 Radio) *1 (with 3.7V/5000mAh lithium battery installed)
• High quality telescopic antenna with SMA connector *1
• USB-A to TYPE-C 1 meter data cable *1
• Storage bag *1

Figure 5: Included accessories.

9. Warranty and Support

As the DP-666 radio's firmware is still under active development, new features and improvements are continuously being released. For the latest information, including updated manuals, videos, and firmware downloads, please visit the official product page:

https://deepelec.com/dp-666

For advanced users, the open-source nature of the project allows for community support and secondary development. Please refer to the provided GitHub links in the introduction for project source code.