Introduction
This manual provides comprehensive instructions for the installation, operation, and maintenance of your Diamond Antenna MR77 Dual-Band Mobile Antenna. Designed for 146/446 MHz frequencies, this antenna features a mini magnet mount and a 13ft RG-58/U cable with a PL-259 connector. Please read this manual thoroughly before use to ensure optimal performance and longevity of your antenna.
Product Overview
The Diamond Antenna MR77 is a compact and versatile dual-band mobile antenna suitable for various applications. Its design prioritizes ease of installation and reliable performance for both VHF and UHF bands.
- Frequency Bands: 146/446 MHz (Dual-Band)
- Antenna Length: Approximately 20 inches
- Gain: 2.15 dBi (146 MHz) / 3.4 dBi (446 MHz)
- Maximum Power: 70 Watts
- Connector Type: PL-259
- Mounting: Mini Magnet Mount (2.6 inch diameter)
- Cable: RG-58/U, approximately 13 feet in length
- Color: Black
Figure 1: Diamond Antenna MR77 Dual-Band Mobile Antenna. This image shows the complete antenna assembly, including the whip, loading coil, magnet base, and coiled coaxial cable with a PL-259 connector.
Setup and Installation
- Unpacking: Carefully remove all components from the packaging. Verify that you have the antenna whip, magnet mount with attached coaxial cable, and PL-259 connector.
- Antenna Assembly:
- Locate the antenna whip and the threaded base on the magnet mount.
- Gently screw the antenna whip onto the threaded connector on the magnet mount until it is finger-tight. Do not overtighten.
- Mounting Location:
- Choose a flat, metallic surface on your vehicle for mounting, such as the center of the roof or trunk lid. This provides an optimal ground plane for antenna performance.
- Ensure the chosen surface is clean and free of dirt or debris to maximize magnetic adhesion and prevent paint scratches. The magnet base is designed with a non-slip rubber pad for protection.
- Place the magnet mount firmly on the chosen surface. The strong rare earth magnet base will secure the antenna.
- Cable Routing:
- Route the 13-foot RG-58/U coaxial cable from the antenna to your radio. Avoid pinching the cable in door jambs or windows, which can damage the cable and affect performance.
- Secure the cable along its path using cable ties or clips to prevent it from flapping or interfering with vehicle operation.
- Connecting to Radio:
- Connect the PL-259 connector at the end of the coaxial cable to the UHF (SO-239) antenna port on your mobile radio.
- Ensure the connection is secure but do not overtighten.
Figure 2: Close-up of the Diamond Antenna MR77 magnet mount base. This image highlights the robust magnet base and the connection point for the antenna whip, emphasizing its compact design.
Installation Video Example
Video 1: Dual band 2 Way 2M-70CM VHF/UHF Antenna installation. This video demonstrates the assembly and mounting of a similar dual-band magnetic mount antenna, showing how to attach the whip to the base and secure it to a vehicle surface, as well as connecting the cable to a radio. Note: This video features a similar product from VFAN and is for illustrative purposes regarding installation steps.
Magnetic Base Features Video
Video 2: HYS Amateur Dual-Band VHF & UHF Magnet Base Antenna overview. This video showcases the features of a magnetic base for a dual-band antenna, including its robust construction and scratch-resistant rubber sleeve, demonstrating its secure attachment to a vehicle and the PL-259 connector.
Operating Instructions
Once the MR77 antenna is properly installed and connected to your mobile radio, it is ready for operation. Ensure your radio is configured for the correct VHF (146 MHz) or UHF (446 MHz) frequencies.
- Frequency Selection: Select the desired operating frequency on your radio within the 146 MHz or 446 MHz bands.
- Power Output: The MR77 antenna is rated for a maximum of 70 watts. Do not exceed this power limit to prevent damage to the antenna or your radio.
- SWR Check: It is recommended to perform a Standing Wave Ratio (SWR) check after initial installation and periodically thereafter to ensure optimal performance and prevent damage to your radio's final amplifier. An SWR of 1.5:1 or lower is generally ideal.
- Signal Reception: For best reception, ensure the antenna is mounted in a clear, unobstructed location on your vehicle.
Antenna Performance Testing Video
Video 3: Bingfu Vehicle Mobile Ham Radio Antenna with Ground Planes. This video demonstrates the SWR testing of a mobile ham radio antenna, showing the measurement process and results for optimal performance. Note: This video features a similar product from Bingfu and is for illustrative purposes regarding antenna testing.
Maintenance
Regular maintenance ensures the longevity and optimal performance of your MR77 antenna.
- Cleaning: Periodically clean the antenna whip and magnet base with a soft, damp cloth. Avoid abrasive cleaners that could damage the finish.
- Connection Check: Ensure all connections (antenna whip to mount, coaxial cable to radio) remain tight and free of corrosion.
- Cable Inspection: Regularly inspect the coaxial cable for any signs of wear, cuts, or kinks. Damaged cables can significantly degrade performance.
- Magnet Base Care: If the antenna is frequently moved, ensure the mounting surface and the rubber pad on the magnet base are clean to prevent scratching the vehicle's paint.
Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Poor signal reception/transmission | Loose connections, damaged cable, improper mounting location, high SWR. | Check all connections. Inspect cable for damage. Relocate antenna to a clearer, metallic surface. Perform SWR check and adjust if necessary. |
| Antenna falling off vehicle | Dirty mounting surface, insufficient magnetic contact. | Clean the vehicle surface and the magnet base thoroughly. Ensure the magnet base is fully seated on a flat metallic surface. |
| Vehicle paint scratches | Dirt or debris trapped under magnet base, frequent repositioning without cleaning. | Always clean the mounting surface and magnet base before placement. Avoid dragging the antenna across the paint. |
Specifications
- Model Number: MR77
- Frequency Range: 146/446 MHz (VHF/UHF Dual-Band)
- Gain: 2.15 dBi (146 MHz), 3.4 dBi (446 MHz)
- Max Power Rating: 70 Watts
- Impedance: 50 Ohms
- VSWR: Less than 1.5:1 (typical)
- Antenna Length: 20 inches (approximately)
- Coaxial Cable: RG-58/U, 13 feet (approximately)
- Connector: PL-259 (UHF Male)
- Magnet Diameter: 2.6 inches
- Weight: 1.2 pounds (approximately)
- Product Dimensions: 22 x 2 x 4 inches (packaging/overall)
Warranty and Support
Diamond Antenna products are manufactured to high-quality standards. For specific warranty information, please refer to the documentation included with your purchase or contact Diamond Antenna customer support directly. Keep your proof of purchase for any warranty claims.
For technical assistance or inquiries, please visit the official Diamond Antenna website or contact their authorized service centers.
