PLJ-096OLED-L1 RF Signal Frequency Counter User Manual

1. Product Overview

The PAREK PLJ-096OLED-L1 is a high-precision RF signal frequency counter module designed for a wide range of applications, including ham radio transceivers, RF test equipment, and educational instruments. It features a 0.96-inch OLED display for clear frequency readout, a stable VC-TCXO reference oscillator, and supports dual intermediate frequency (IF) offset modes.

Key Features

• 100MHz Measurement Range: Capable of measuring frequencies from 1kHz to 100MHz.
• ±2.5ppm Stability: Utilizes a KDS/EPSON VC-TCXO reference oscillator for high accuracy.
• Dual IF Offset: Supports independent ±99.9999MHz offset with 100Hz step resolution.
• OLED Display: Features a 0.96-inch, 8-digit high-visibility OLED screen.
• Low Power Consumption: Operates at approximately 30mA @5V, includes an electronic power switch.
• UART Interface: Provides a serial port output for data logging and system integration.

2. Technical Specifications

The following table details the technical specifications of the PLJ-096OLED-L1 module:

The sensitivity of the module can vary slightly depending on the position of the sensitivity adjustment potentiometers. Refer to the test data for typical performance:

3. Setup and Connections

This section guides you through connecting the PLJ-096OLED-L1 module.

Package Contents

• PLJ-096OLED-L1 Module ×1
• IPEX-to-SMA(M) Cable (15cm) ×1
• XH2.54-2P Power Cable (15cm) ×1

Connecting the Module

1. Power Connection: Connect the provided XH2.54-2P power cable to the [PWR] interface on the module. Connect the other end to a 4.5-9V DC power source (5V recommended).
2. Signal Input: Attach the IPEX-to-SMA(M) cable to the [RF IN] port on the module. Connect the SMA end to your RF signal source.
3. Serial Data Output (Optional): For data logging or integration with other systems, connect to the [UART] TTL serial interface. The baud rate is configurable.

4. Operating Instructions

The module is controlled via two buttons, K1 and K2, and displays frequency on the OLED screen.

Basic Operation

• Power On/Off: The module has an electronic power switch. Ensure proper voltage is supplied.
• Frequency Display: Once powered and a signal is applied to the RF IN, the frequency will be displayed on the OLED screen. The refresh rate is 0.64s for real-time monitoring.

Button Functions (K1 & K2)

• K1 (Setting/Confirmation Key): Used to enter settings menus and confirm selections.
• K2 (Adjustment Key): Used to navigate through options or adjust values within settings.

Dual IF Operation

The module supports dual intermediate frequency (IF) offset modes. This is particularly useful for transceivers where the displayed frequency needs to be offset from the actual received or transmitted frequency.

• Setting IF Offset: Use K1 and K2 to access and configure the IF1 and IF2 offset values. These can be set independently with a ± offset mode.
• Offset Range: Each IF can be offset by ±99.9999MHz in 100Hz steps.
• Saving Settings: All settings, including IF offsets, are retained in EEPROM memory.

Gate Time Selection

The gate time determines the measurement resolution and update speed.

• 0.64s Gate Time: Provides 10Hz resolution. Ideal for faster updates.
• 1.0s Gate Time: Provides 1Hz resolution. Offers higher precision for stable signals.
• Select the desired gate time using the K1 and K2 buttons in the settings menu.

UART Data Output

The module outputs frequency data via its TTL serial interface. The default format is: "FREQ:xxxx.xxx kHz\n".

This allows for external logging or integration with microcontrollers and other digital systems.

5. Maintenance and Calibration

VC-TCXO Calibration

• The module comes with a factory-calibrated VC-TCXO (Voltage Controlled Temperature Compensated Crystal Oscillator) with an accuracy of ±2.5ppm at 25°C.
• For field recalibration, a test point labeled TP1 is available on the PCB. This allows for fine-tuning the frequency reference if necessary, using appropriate test equipment.

General Care

• Keep the module clean and free from dust and moisture.
• Avoid exposing the module to extreme temperatures or direct sunlight.
• Handle with care to prevent physical damage to the PCB or OLED display.

6. Troubleshooting

Common Issues and Solutions

• No Display/Module Not Powering On:
  • Verify the power supply voltage is within the 4.5-9V DC range (5V recommended) and correctly connected to the XH2.54-2P port.
  • Check for any short circuits or loose connections.
  • If the electronic switch fails, short-circuiting J1 on the PCB might bypass it (refer to Figure 4).
• Incorrect Frequency Reading:
  • Ensure the RF signal input is correctly connected to the IPEX (Gen1) port.
  • Check the input signal strength; the module has a typical sensitivity of -10dBm. Weak signals may not be accurately measured.
  • Verify IF offset settings are correct for your application. The default IF is 0 for direct frequency readout.
  • Consider recalibrating the VC-TCXO if significant drift is observed (see Section 5).
• Unstable Readings:
  • Ensure the input RF signal is stable and free from excessive noise.
  • Try adjusting the gate time setting; a longer gate time (1.0s) can provide more stable readings at the cost of update speed.

7. User Tips

• Default IF Setting: Remember that the default Intermediate Frequency (IF) is set to 0. If you require an offset for your application (e.g., in a superheterodyne receiver), you must configure IF1 or IF2 using the K1 and K2 buttons.
• Trailing Zero Blanking: For signals above 1MHz, enabling trailing zero blanking in the settings can improve readability by suppressing unnecessary digits.
• UART Output for Logging: The UART serial output is a powerful feature for data logging. Connect it to a microcontroller or a serial-to-USB adapter to capture frequency readings over time for analysis. The output format is fixed to "FREQ:xxxx.xxx kHz\n".
• Power Supply Quality: Use a stable and clean 5V DC power supply for optimal performance and accuracy, especially in sensitive RF environments.

8. Warranty and Support

For technical support, warranty claims, or further inquiries regarding the PLJ-096OLED-L1 frequency counter, please contact your retailer or the manufacturer directly. Keep your purchase receipt as proof of purchase.