1. Introduction
This manual provides detailed instructions for the installation, operation, and maintenance of your Diamond Original HF40FXW 40m HF Mobile Antenna. Please read this manual thoroughly before using the antenna to ensure proper setup and optimal performance. This antenna is designed for amateur radio use on the 40-meter band (7.00 MHz).
2. Product Overview
The Diamond HF40FXW is a compact, high-efficiency mobile antenna specifically designed for the 40-meter HF band. It features a 1/4 wave design with base loading and an MJ connector, making it suitable for vehicle installations. Its robust construction ensures reliable performance for amateur radio enthusiasts.
Figure 1: Diamond HF40FXW 40m HF Mobile Antenna. The image shows the full length of the antenna, approximately 1.40m, alongside a magnified view of its MJ connector base. The antenna is slender and black, with a metallic base, indicating its robust construction for mobile use.
3. Key Features
- Frequency Band: Optimized for 40 meters (7.00 MHz).
- Design: 1/4 wave mobile antenna with base loading.
- Impedance: 50 Ohms.
- Connector: UHF Male (MJ type) / SO-239.
- VSWR: 1.5:1 (Nominal).
- Maximum Power: 200W (SSB).
- Length: Approximately 140 cm (1.4 meters).
- Construction: Features a 3-stage distributed coil system for high efficiency and a new mechanism for frequency adjustment by sliding the element.
4. Setup and Installation
Proper installation is crucial for optimal antenna performance and safety. Follow these steps carefully:
- Mounting Location: Select a sturdy mounting location on your vehicle that provides a clear, unobstructed view of the sky. Common locations include trunk lids, fender mounts, or roof mounts. Ensure the mount is securely grounded to the vehicle chassis for best performance and safety.
- Antenna Base Installation: Attach the antenna base (with the MJ connector) to your chosen mount. Ensure a tight and secure connection.
- Antenna Element Assembly: Carefully screw the antenna element onto the base. Do not overtighten.
- Coaxial Cable Connection: Connect a high-quality 50-ohm coaxial cable (with a PL-259 connector) from your transceiver to the antenna's MJ connector. Ensure the connection is secure and weatherproof.
- Grounding: Verify that your antenna mount and coaxial cable shield are properly grounded to the vehicle's chassis. A good ground plane is essential for mobile antenna performance.
5. Operating Instructions
Once installed, the HF40FXW antenna requires minimal tuning for operation on the 40-meter band.
- SWR Check: Before transmitting, always check the Standing Wave Ratio (SWR) using an SWR meter. The nominal VSWR for this antenna is 1.5:1. An SWR reading above 2.0:1 indicates a mismatch and should be addressed before transmitting to prevent damage to your transceiver.
- Frequency Adjustment: The HF40FXW features a sliding element for fine-tuning the frequency. If your SWR is high, carefully adjust the length of the element by sliding it up or down until the lowest SWR is achieved within your desired operating frequency range on the 40-meter band.
- Power Limit: Do not exceed the maximum power rating of 200W (SSB). Exceeding this limit can damage the antenna.
- Safe Operation: Always ensure the antenna is clear of obstructions and power lines before transmitting. Never operate the antenna near high-voltage sources.
6. Maintenance
Regular maintenance will prolong the life and performance of your antenna.
- Cleaning: Periodically clean the antenna with a soft, damp cloth to remove dirt, dust, and road grime. Avoid abrasive cleaners.
- Connection Check: Regularly inspect all connections (antenna to mount, coaxial cable to antenna, coaxial cable to transceiver) for corrosion, looseness, or damage. Clean and tighten as necessary.
- Physical Inspection: Check the antenna element for any signs of bending, cracking, or other physical damage. Ensure the base loading coil is intact.
- Weather Protection: While designed for outdoor use, extreme weather conditions can affect performance. Consider removing the antenna during severe storms or when not in use for extended periods.
7. Troubleshooting
If you experience issues with your HF40FXW antenna, consider the following common problems and solutions:
| Problem | Possible Cause | Solution |
|---|---|---|
| High SWR | Poor grounding, incorrect element length, damaged cable/connector, nearby metal objects. | Check ground connection, adjust element length, inspect/replace cable/connector, relocate antenna if possible. |
| Poor Reception/Transmission | High SWR, antenna not tuned, faulty coaxial cable, transceiver issue. | Perform SWR check and tune antenna, test coaxial cable, verify transceiver functionality. |
| Antenna Noise | Vehicle electrical interference, poor grounding. | Improve vehicle grounding, install noise filters on vehicle electrical system. |
8. Specifications
| Parameter | Value |
|---|---|
| Model Number | HF40FXW |
| Frequency Band | 7.00 MHz (40 meters) |
| Impedance | 50 Ohms |
| VSWR (Nominal) | 1.5:1 |
| Maximum Power | 200W (SSB) |
| Antenna Length | 140 cm (1.4 meters) |
| Connector Type | UHF Male (MJ / SO-239) |
| Element Phasing | 1/4 wave at base |
9. Warranty and Support
For warranty information or technical support regarding your Diamond HF40FXW antenna, please refer to the documentation provided at the time of purchase or contact your authorized Diamond dealer or the manufacturer directly. Keep your purchase receipt as proof of purchase.
