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Ats-20 Radio Manual

This guide provides a comprehensive overview of the ATS-20+ Si4732 All Band Radio Receiver Go to product viewer dialog for this item. . The is a compact (approx.

) receiver popular for its capability to tune FM, AM, LW, and Shortwave (SSB) frequencies on a budget. 1. Key Controls & Interface

The device features an OLED display and a set of eight buttons, typically running firmware version 3.0.7g by PU2CLR.

Encoder/TUNE: Rotate to adjust frequency. Pull the encoder to adjust BFO.

BAND+/BAND-: Short press to select bands (FM, AM, LW, SW); long press to browse bands backward. ats-20 radio manual

VOL+/VOL-: Short press to enter volume mode (use encoder to adjust). STEP: Adjust tuning steps (

BFO/MOD/ATS: In SSB mode, press for BFO regulation. Long press to engage Automatic Tuning System. 2. Operation Modes FM Mode: Operates between . Uses 3.5mm headphone jack for antenna. AM/LW/SW: Covers

SSB (USB/LSB): Used for ham radio operators. To select modulation, use the mode button (or BFO button). Bandwidth: The BFO knob allows for selectable filters ( ) to improve audio quality. 3. Power & Hardware Battery: Internal lithium battery (typically hours runtime). Charging: USB-C connector on the rear.

Antenna: BNC connector for a telescopic whip antenna or external antenna (highly recommended for shortwave). 4. Quick Fixes & Tips This guide provides a comprehensive overview of the

Wrong Direction Encoder: If the encoder works in reverse, the Arduino sketch needs two numbers swapped, and the firmware reflashed.

Low Volume: Ensure the BFO settings are adjusted properly for SSB, as it can sound low/weak by default.

Weak Signals: For better shortwave reception, use an external wire antenna connected to the BNC input. 5. Troubleshooting

Frozen/Wrong Station: Access the menu via the button and select "EEPROM RESET" to factory default the settings. Visual inspection: check for cracked solder joints, corroded

No SSB Activity: Ensure the antenna is long enough; a 20-meter wire is recommended for effective Shortwave reception.

Key maintenance and alignment steps

  1. Visual inspection: check for cracked solder joints, corroded connectors, electrolytic capacitor leakage, and loose hardware.
  2. Power supply check: confirm correct DC voltages on regulator outputs and rails before powering RF stages; verify current draw under no-signal conditions.
  3. RX alignment (typical procedure):
    • Connect signal generator to antenna input (use appropriate attenuation).
    • Set the receiver to a known frequency and mode (usually CW or SSB).
    • Peak the RF front-end and IF transformer adjustments for maximum output at the specified points (follow service manual frequency points if available).
    • Adjust discriminator/IF alignment for minimum distortion and correct center frequency.
  4. TX alignment:
    • Use a dummy load and wattmeter.
    • With low drive, set driver bias and adjust driver/PA tuning for clean waveform and maximum power.
    • Check output harmonics with a spectrum analyzer or harmonic filter; adjust tuning to minimize spurious emissions.
  5. Carrier suppression and balance (for SSB): adjust the balanced modulator/USB/LSB phasing and carrier null to maximize suppression of unwanted carrier and opposite sideband.
  6. Final checks: verify SWR on the antenna connector is acceptable, perform RX sensitivity and S-meter checks against known signals, and check TX power and audio quality.

Selecting a Band

Press B repeatedly:

  • FM: 64–108 MHz (default 87–108)
  • SW: 2.3–26.1 MHz (continuous)
  • MW: 522–1710 kHz
  • LW: 153–279 kHz

Chapter 9: Troubleshooting Common Problems (Not in the Official Manual)

| Problem | Likely Cause | Solution | | :--- | :--- | :--- | | Radio won't turn on | Dead 18650 battery | Recharge via USB-C for 4 hours. Use a 1A charger. | | No SSB audio | Wrong sideband or BFO offset | Toggle USB/LSB. Access hidden menu to adjust BFO. | | FM sounds distorted | Overload | Extend the antenna only partially. Enable FM RF gain if available. | | Display flickers | Low battery voltage | Replace or recharge the 18650. | | Can't hear AM stations | Bandwidth too narrow | Short press Filter until set to 6.0 kHz or higher. | | Encoder skips frequencies | Dirty encoder | Rotate the knob rapidly 20 times. Or open and spray contact cleaner. |

2. Getting Started