LMR-500 Coaxial Cable: Bridging the Gap Between Standard and Heavy-Duty RF Feeders

In demanding RF deployments, engineers frequently encounter a frustrating gap: LMR-400 is just too lossy for the required distance or frequency, yet stepping up to LMR-600 introduces excessive weight, stiffness, and cost. LMR-500 was engineered to solve this precise optimization problem. With an outer diameter of 0.500 inches (12.7 mm), it delivers approximately 25% lower attenuation than LMR-400 at 2.4 GHz while maintaining field-installable flexibility that heavier cables simply cannot match. For high-performance 5G, long-haul Wi-Fi backhaul, and high-power broadcast links, LMR-500 represents the optimal balance of electrical performance and mechanical practicality.

What Is LMR-500?

LMR-500 is a 50-ohm, ultra-low-loss flexible coaxial cable positioned between LMR-400 and LMR-600 in the Times Microwave (Amphenol) product family. It features a large-diameter solid bare copper-clad aluminum (BCC) center conductor, precision foam PE dielectric, and bonded dual-layer shielding. Unlike semi-rigid or corrugated alternatives, LMR-500 retains true flexibility for routing through conduits, around tower structures, and into equipment shelters without specialized bending tools.

Key Technical Advantages

1.   Measurably Lower Loss Than LMR-400

At 2.4 GHz, LMR-500 exhibits approximately 5.1 dB/100 ft attenuation versus LMR-400’s 6.8 dB/100 ft—a 25% improvement. At 5.8 GHz, the advantage widens to ~30%. This extra margin translates directly to longer viable link distances, reduced amplifier requirements, or improved SNR at the receiver.

2.   Superior Power Handling for High-Wattage Systems

With peak operating voltage exceeding 5,000 Vrms and average power ratings above 1,800W at 1 GHz, LMR-500 safely handles high-power transmitter outputs for FM broadcast, amateur radio EME, and radar systems where LMR-400 would approach thermal limits.

3.   Field-Friendly Flexibility at 0.5" OD

Despite its larger size, LMR-500 maintains a repeated bend radius of just 5 inches (127 mm). This is significantly more manageable than LMR-600 (7.5" bend radius) and eliminates the need for pre-formed bends or hydraulic benders required by semi-rigid cables of comparable performance.

4.   Bonded Shield Moisture Resistance

Like all genuine LMR-series cables, LMR-500 uses bonded foil construction that prevents longitudinal moisture migration—a critical reliability factor for outdoor aerial and direct-burial installations where traditional non-bonded RG-214 equivalents fail prematurely.

Quick Specifications at a Glance

Note: Always verify against your supplier’s official datasheet. Specifications may vary between genuine Amphenol/Times Microwave products and third-party equivalents.

Primary Applications

● 5G NR Macro Sites: Extended feeder runs (30–60m) at 3.5 GHz and 4.9 GHz bands where LMR-400 loss exceeds link budget.

● Long-Haul Wi-Fi Backhaul: Point-to-point bridge feeds at 5.x GHz requiring maximum signal margin.

● FM/TV Broadcast Translators: High-power feeder lines for medium-power transmitters and combiner outputs.

● Amateur Radio EME & Contest Stations: Low-loss feeds for large Yagi arrays and high-power amplifiers at 432 MHz and above.

● Military & Defense Radar: Mobile radar antenna feeds requiring both low loss and rapid deployability.

● GPS/GNSS Precision Timing Networks: Campus-wide distribution with minimal delay variation over extended distances.

LMR-500 Positioning in the Full LMR Family

Critical Engineering & Procurement Notes

● Connector Specificity Is Non-Negotiable: LMR-500 requires dedicated LMR-500 connectors. Do not attempt to use LMR-400 or LMR-600 connectors—the center conductor diameter, braid capture geometry, and crimp dimensions are unique. Improper termination causes VSWR degradation, PIM issues, and potential arcing under high power.

● Availability & Lead Time Considerations: LMR-500 is less commonly stocked than LMR-400 or LMR-600. For project-critical deployments, confirm inventory and lead times early. Some distributors offer certified equivalents (e.g., Pasternack PE-C500, MPD LMR-500-EQ) with matching specifications when genuine Amphenol stock is unavailable.

● Weight & Support Spacing: At ~0.14 lb/ft (0.21 kg/m), LMR-500 is noticeably heavier than LMR-400. Ensure cable hangers, clips, and conduit supports are rated for the increased weight, especially in vertical tower runs. Follow manufacturer-recommended support spacing (typically every 2–3 feet vertically).

● PIM-Sensitive Deployments: For multi-carrier 5G DAS or sites requiring PIM < -155 dBc, specify Low-PIM LMR-500 variants. Standard LMR-500 is adequate for single-carrier Wi-Fi, amateur radio, and non-critical broadcast links.

● Cost-Benefit Validation: Before specifying LMR-500, run a full link budget comparing it against LMR-400 + inline amplifier vs. LMR-600. In many cases, the total installed cost (cable + connectors + labor) of LMR-500 is lower than LMR-600 while outperforming amplified LMR-400 solutions in reliability and noise figure.

Conclusion

LMR-500 exists for engineers who refuse to compromise. When LMR-400 falls short on loss or power, and LMR-600 exceeds mechanical or budgetary constraints, LMR-500 delivers precisely calibrated performance without excess. Its combination of sub-6 GHz ultra-low attenuation, high power handling, and genuine field flexibility makes it an indispensable tool for next-generation wireless infrastructure. While less ubiquitous than its 400 and 600 siblings, LMR-500 remains the definitive solution for projects where every dB and every installation hour counts.

Evaluating LMR-500 for your next deployment? [Request a Custom Quote] for bulk cable and matched connectors, or [Consult Our RF Engineers] for link budget validation and alternative analysis. We help you select the right cable—not just the biggest one.