LMR-400 vs RG58: Which Coaxial Cable Should You Choose?

Published by Wassalat Technical Team

Choosing between LMR-400 and RG58 coaxial cables is one of the most common dilemmas for anyone setting up a wireless network, radio system, or antenna installation. Both are 50Ω cables, but their performance, construction, and applications are worlds apart.

This comprehensive guide compares LMR-400 and RG58 side-by-side—covering signal loss, construction, flexibility, cost, and ideal applications—so you can make the right choice for your project.

Quick Overview

The short answer is: for most modern, performance-critical applications, LMR-400 is the superior choice. The core difference lies in signal loss (attenuation) and intended application.

LMR-400 – The Low-Loss Champion

What it is: A professional-grade, ultra-low-loss 50Ω coaxial cable designed for high-performance, long-distance RF applications.

Key Strengths: Ultra-low signal loss, high frequency support (6 GHz), outdoor-rated, durable

Best For: Long cable runs, outdoor antennas, base stations, WISPs, 4G/5G, WiFi

RG58 – The Flexible & Affordable Option

What it is: A thin, flexible, budget-friendly 50Ω coaxial cable that has been a staple in the RF world for decades.

Key Strengths: Excellent flexibility, low cost, easy to work with

Best For: Short patch cables, test leads, internal equipment connections, mobile installations

Key Specifications Comparison

Signal Loss (Attenuation) Comparison

Signal loss is the single most important difference between LMR-400 and RG58. LMR-400 has dramatically lower loss at all frequencies.

Attenuation Table

Real-World Impact

Here's what these numbers mean in practice:

• At 100 MHz (FM Radio): A 100-foot run of LMR-400 loses 1.5 dB; RG58 loses 4.5 dB. The LMR-400 signal is twice as strong at the receiver.
• At 900 MHz (Cellular): A 100-foot run of LMR-400 loses 3.9 dB; RG58 loses 16.0 dB. The LMR-400 signal is over 15 times stronger at the receiver.
• At 2.4 GHz (WiFi): LMR-400 can run 100 feet with acceptable loss. RG58 is essentially unusable at this frequency for any run over a few feet.

Construction Differences

The physical construction of these cables explains their performance differences:

LMR-400 Construction

• Center Conductor: 13 AWG solid copper (thicker = lower resistance)
• Dielectric: Foam polyethylene (air bubbles reduce loss)
• Shield: Foil + double copper braid (triple shielding)
• Jacket: Polyethylene (PE) – UV and water resistant
• Result: Ultra-low loss, weather-resistant, high durability

RG58 Construction

• Center Conductor: 20 AWG stranded or solid tinned copper (thinner = higher resistance)
• Dielectric: Solid polyethylene (higher loss than foam)
• Shield: Single copper braid (90-95% coverage)
• Jacket: PVC (not UV resistant, not for outdoor use)
• Result: Flexible, low cost, higher loss, indoor only

LMR-400: The Low-Loss Champion

LMR-400 is a professional-grade 50Ω coaxial cable designed for minimal signal loss and maximum performance.

Why Choose LMR-400?

Common LMR-400 Applications

• ? Cellular base stations (4G/5G)
• ? WiFi access points and outdoor antennas
• ? WISP and point-to-point wireless links
• ?️ GPS and GNSS systems
• ? Amateur radio (HF, VHF, UHF)
• ? DAS (Distributed Antenna Systems)
• ? Microwave and backhaul links

RG58: The Flexible & Affordable Option

RG58 is a thinner, more flexible 50Ω cable that has been a staple in the RF world for decades. Its main advantages are low cost and high flexibility.

Why Choose RG58?

Common RG58 Applications

• ? Short patch cables (under 10 feet)
• ? Test leads and laboratory equipment
• ? Internal equipment connections
• ? Mobile installations (vehicles)
• ? Amateur radio (VHF/UHF)
• ? Temporary setups
• ? Prototyping and development

Side-by-Side Comparison Table

Applications: When to Use Each

WiFi & Wireless Networks

Cellular / Mobile

Amateur Radio

How to Decide: LMR-400 or RG58?

Flowchart Decision Guide

1. How long is your cable run?
   • Under 10 feet → Consider RG58
   • 10-20 feet → Either cable works; LMR-400 preferred
   • Over 20 feet → Choose LMR-400
2. What frequency are you using?
   • Below 100 MHz → Both work; RG58 may be sufficient for short runs
   • 100 MHz to 1 GHz → LMR-400 is strongly recommended
   • Above 1 GHz (WiFi, 5G, etc.) → Must use LMR-400
3. Is the installation outdoors?
   • Yes → Must use LMR-400 (PE jacket)
   • No → Both work; RG58 is more flexible
4. What is your power level?
   • Low power (under 100W) → Both work
   • High power (100W+) → LMR-400 recommended
5. What is your budget?
   • Budget-conscious → RG58 for short, indoor runs
   • Performance-critical → Invest in LMR-400

Quick Decision Table

Frequently Asked Questions (FAQ)

1. What is the main difference between LMR-400 and RG58?

The main difference is signal loss. LMR-400 has significantly lower attenuation (signal loss) than RG58, especially at higher frequencies. LMR-400 also has better shielding and an outdoor-rated jacket.

2. Can I use RG58 for WiFi?

No. RG58 is not recommended for WiFi (2.4 GHz or 5 GHz) runs longer than 1-2 feet. The signal loss is catastrophic. Use LMR-400 or LMR-240 for WiFi applications.

3. Can I use LMR-400 for CB radio?

Yes. LMR-400 works very well for CB radio (27 MHz). However, it's overkill for this application—RG58 or RG-8 would also work fine for CB frequencies.

4. Is LMR-400 worth the extra cost?

For long runs, high frequencies, or outdoor installations, yes, absolutely. The performance difference is dramatic. For short, indoor, low-frequency runs, RG58 is more cost-effective.

5. Can I use RG58 outdoors?

No. RG58 has a PVC jacket that degrades in sunlight. It will crack and fail within 1-2 years outdoors. Use LMR-400 with a PE jacket for outdoor installations.

6. What connectors do LMR-400 and RG58 use?

Both cables use 50Ω connectors. Common options include:

• LMR-400: N-Type, SMA, UHF/PL-259
• RG58: BNC, SMA, UHF/PL-259

7. Which cable is more flexible?

RG58 is much more flexible than LMR-400. RG58's 0.195" diameter and stranded conductor make it easy to route in tight spaces.

8. How long can LMR-400 run for 5G?

For 5G Sub-6 (3.5-6 GHz), LMR-400 can run 50-100 feet with acceptable loss. For longer runs, consider LMR-600 or a signal amplifier.

9. How long can RG58 run for VHF?

For VHF (144 MHz), RG58 can run 20-30 feet with acceptable loss. For longer runs, RG8 or LMR-400 is recommended.

10. Is there a cable between LMR-400 and RG58?

Yes. LMR-240 is a good middle-ground option. It's more flexible than LMR-400 but has lower loss than RG58. LMR-195 is another option for shorter runs.

11. Can I use RG58 for 4G LTE?

For short runs (under 10 feet), RG58 can work for 4G LTE. For longer runs, LMR-400 is strongly recommended to maintain signal quality.

12. What is the power handling of LMR-400 vs RG58?

LMR-400 can handle higher power than RG58 due to its thicker conductor. At 100 MHz, LMR-400 can handle ~500W, while RG58 handles ~100W.

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Last Updated: July 2026

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