Best Coax for Every Situation: RG-58, RG-8X, LMR-400, and Hardline

You can spend $2,000 on a radio and $500 on an antenna, then lose half your signal in cheap coax. It happens constantly. The feedline between your rig and antenna is where power goes to die quietly, and most hams don't give it nearly enough thought.

Street prices in this article were checked in July 2026 and move around; verify with a dealer such as HRO, DX Engineering, or GigaParts before you buy.

I've been through every major coax type over 20 years of operating. Started with whatever RadioShack stocked, graduated to Times Microwave products, and eventually ran hardline for a fixed station. Each type has a place. None is universally "best."

This guide gives you actual loss numbers, real-world trade-offs, and clear recommendations for specific use cases. No generic "it depends" hedging.

How Coax Loss Works (Quick Version)

Coaxial cable loss comes from two sources:

1. Conductor loss (resistive heating in the center conductor and shield) — dominates at lower frequencies
2. Dielectric loss (heating in the insulating material between conductors) — dominates at higher frequencies

Both increase with frequency. A cable that's perfectly fine at 7 MHz might be unacceptable at 432 MHz. This is why "what coax should I use?" always requires knowing your frequency.

Loss is specified in dB per 100 feet at specific frequencies. Every 3 dB of loss means half your power never reaches the antenna. Think about that: 100 watts into the rig, 50 watts out the antenna. The other 50 watts heats your cable.

Not great.

The Four Main Contenders

RG-58: The Lightweight Compromise

Specs:

• Impedance: 50 ohms
• Outer diameter: 0.195" (about 5mm)
• Velocity factor: 0.66 (solid PE) or 0.78 (foam)
• Loss at 30 MHz: 1.4 dB/100 ft
• Loss at 146 MHz: 3.3 dB/100 ft
• Loss at 440 MHz: 5.9 dB/100 ft
• Max power at 30 MHz: 350W
• Connectors: BNC or PL-259 (with adapter)

RG-58 is thin, flexible, cheap (about $0.30-0.50/ft for decent quality), and lossy. At VHF/UHF, it's a heater, not a feedline.

But here's when RG-58 makes sense:

• Short jumper cables (under 6 feet) at any frequency
• Portable/field operations where weight matters more than loss
• HF runs under 50 feet where the loss is still manageable
• Test bench connections
• Temporary installations

A 25-foot run of RG-58 at 14 MHz loses about 0.5 dB. That's less than 11% of your power. Totally acceptable for a portable setup. That same 25 feet at 446 MHz loses 1.5 dB — about 29% gone. Now it hurts.

RG-8X: The Sweet Spot for Most Hams

Specs:

• Impedance: 50 ohms
• Outer diameter: 0.242" (about 6.1mm)
• Velocity factor: 0.82 (foam dielectric)
• Loss at 30 MHz: 1.0 dB/100 ft
• Loss at 146 MHz: 2.3 dB/100 ft
• Loss at 440 MHz: 4.1 dB/100 ft
• Max power at 30 MHz: 600W
• Connectors: PL-259 direct fit

RG-8X (sometimes called mini-8) is genuinely the sweet spot for a huge number of ham installations. It's about 30% less lossy than RG-58, still flexible enough to route easily, takes standard PL-259 connectors without adapters, and costs around $0.50-0.80/ft.

I ran RG-8X for my first decade as a ham. Fed a G5RV on HF, fed a vertical for 2m, no complaints. For runs under 75 feet on HF or under 30 feet at VHF, it's hard to argue with the price-to-performance ratio.

Where RG-8X falls short: long runs (100+ feet), VHF/UHF base stations, or any situation where you're counting dBs. At 440 MHz with a 100-foot run, you're losing over 4 dB. That's 60% of your power gone.

LMR-400: The Performance Standard

Specs:

• Impedance: 50 ohms
• Outer diameter: 0.405" (about 10.3mm)
• Velocity factor: 0.85
• Loss at 30 MHz: 0.7 dB/100 ft
• Loss at 146 MHz: 1.5 dB/100 ft
• Loss at 440 MHz: 2.7 dB/100 ft
• Max power at 30 MHz: 2500W (average), much higher at reduced duty cycle
• Connectors: N-type preferred, PL-259 with specific connectors

LMR-400 (manufactured by Times Microwave) is where most serious fixed stations land. It's a significant step up in performance from RG-8X — roughly 40% less loss across the board.

The catch: it's stiffer. You can't make tight bends with LMR-400 (minimum bend radius is about 1 inch). It's 0.4 inches in diameter, so routing through walls and conduit takes planning. And proper connectors require either crimp tools or specific solder-on types.

Cost is around $1.00-1.50/ft from reputable vendors. Watch out for "LMR-400 equivalent" or "LMR-400 type" cables from no-name brands — some are decent (DX Engineering's equivalent is solid), others use cheaper dielectric or thinner copper-clad aluminum center conductors that corrode over time.

For a permanent station running VHF or UHF with any run over 30 feet, LMR-400 is the right call. On HF with runs under 100 feet, it's nice but not strictly necessary — the difference between LMR-400 and RG-8X at 14 MHz over 75 feet is about 0.5 dB. You'd never notice.

I upgraded from RG-8X to LMR-400 for my 2-meter base station (73-foot run to a roof antenna). Gained about 1.5 dB. That translated to roughly one S-unit improvement on receive and noticeably better reports from distant repeaters. Worth the $110 in cable.

Hardline: Maximum Performance

Specs (7/8" hardline):

• Impedance: 50 ohms
• Outer diameter: 0.875" (22mm)
• Velocity factor: ~0.92 (air dielectric)
• Loss at 30 MHz: 0.19 dB/100 ft
• Loss at 146 MHz: 0.44 dB/100 ft
• Loss at 440 MHz: 0.77 dB/100 ft
• Max power: 5000W+ easily
• Connectors: Specialized N or 7-16 DIN

Hardline (semi-rigid or corrugated copper coax with air or foam dielectric) is commercial-grade feedline. Cell towers use this. TV transmitter sites use this. Hams scrounge it from tower decomissioning jobs and surplus sales.

The loss figures speak for themselves: 7/8" hardline at 440 MHz loses less per 100 feet than RG-8X loses at 30 MHz. It's almost like having no feedline at all.

But the downsides are real:

• It's rigid. Routing requires planning and sweeping bends.
• Connectors are expensive ($25-75 each) and require specialized prep tools.
• It's heavy. A 100-foot roll of 7/8" hardline weighs about 50 lbs.
• New, it's $5-15/ft. Surplus is cheaper but you need to check for moisture ingress.
• Grounding and weatherproofing are more involved.

Honestly, unless you're running UHF with a 100+ foot tower run, or you found surplus hardline cheap, LMR-400 is the sensible choice for most hams. Hardline is an optimization for people who've already optimized everything else. Seriously.

The Loss Comparison Table

Here's what matters: actual dB loss for common run lengths.

50-foot run:

Cable 14 MHz 50 MHz 146 MHz 440 MHz RG-58 0.6 dB 1.1 dB 1.7 dB 3.0 dB RG-8X 0.4 dB 0.8 dB 1.2 dB 2.1 dB LMR-400 0.3 dB 0.5 dB 0.8 dB 1.4 dB 7/8" Hardline 0.08 dB 0.15 dB 0.22 dB 0.39 dB

100-foot run:

Cable 14 MHz 50 MHz 146 MHz 440 MHz RG-58 1.2 dB 2.2 dB 3.3 dB 5.9 dB RG-8X 0.8 dB 1.5 dB 2.3 dB 4.1 dB LMR-400 0.5 dB 1.0 dB 1.5 dB 2.7 dB 7/8" Hardline 0.15 dB 0.29 dB 0.44 dB 0.77 dB

Look at that 440 MHz column. 100 feet of RG-58 loses 5.9 dB — that's 74% of your power gone before it ever reaches the antenna. With LMR-400 you lose 2.7 dB (46%). With hardline, only 0.77 dB (16%). This is why UHF operators obsess over feedline.

Connectors Matter More Than You Think

Good cable with bad connectors is worse than mediocre cable with good connectors. I've seen guys run LMR-400 and then put terrible PL-259 connectors on with cold solder joints.

Some straight talk on connectors:

• PL-259/SO-239: Fine for HF. Technically not a constant-impedance connector, but below 30 MHz it doesn't matter. Above 2 meters, the loss and mismatch from a PL-259 starts to add up. They're also not waterproof without additional sealing.
• N-type: Proper 50-ohm connector, weatherproof by design, good through 11 GHz. Use these for VHF/UHF. Period.
• BNC: Great for test leads and portable equipment. Not ideal for permanent outdoor installations.
• SMA: For handhelds and SDR dongles. Too fragile for repeated connection cycles on larger equipment.

For outdoor connections, no matter what connector type: seal them. Self-amalgamating tape (Scotch 2228 or equivalent), then a layer of electrical tape over that. Water in a connector will corrode it and add loss over months. I found 3 dB of extra loss in my 2m feedline once — turned out to be a corroded PL-259 joint at the antenna. Replaced the connector, problem solved.

My Recommendations by Use Case

Portable/field ops (POTA, SOTA, Field Day): RG-8X in 25-50 foot lengths with pre-made connectors. Light enough to carry, low enough loss for HF, and if it gets damaged in the field it's cheap to replace. I keep three pre-cut lengths: 25 ft, 35 ft, and 50 ft.

HF base station, run under 75 feet: RG-8X is fine. The cost difference between RG-8X and LMR-400 for a 60-foot run is about $40-60. The performance difference at HF is maybe 0.3 dB. Spend that $50 on a better antenna instead.

HF base station, run over 75 feet: LMR-400. Now the loss difference starts to be meaningful, especially on 10 meters.

VHF base station (2 meters), any length: LMR-400 minimum. Even a 30-foot run of RG-8X at 146 MHz loses 0.7 dB. LMR-400 loses 0.45 dB for the same run.

UHF base station (70 cm), any length: LMR-400, and keep the run as short as possible. If you can put the radio at the antenna (remote head), do that.

Tower runs over 100 feet at VHF/UHF: Hardline if you can get it. This is where the investment genuinely pays off.

Jumper cables (rig to patch panel, short hops): RG-58 or RG-8X. Under 6 feet, it doesn't matter.

Where to Buy (Without Getting Ripped Off)

Stick with known sources:

• DX Engineering: Their house-brand cables are genuine quality. Custom-cut lengths with tested connectors.
• Times Microwave directly: For LMR-400. They're the original manufacturer.
• The Wireman: Bulk cable, great prices, long track record in ham radio.
• Davis RF: Another solid bulk cable source.

Avoid random Amazon listings for "LMR-400" from brands you've never heard of. Some of it is fine. Some of it is copper-clad steel with cheap foam that absorbs moisture within a year. The few dollars you save isn't worth troubleshooting mysterious signal loss two years later.

One Last Thing About SWR and Loss

High SWR on a lossy feedline can mask antenna problems. Here's why: cable loss reduces the reflected power that makes it back to your rig. A 3:1 SWR at the antenna, measured through 100 feet of RG-58 at 440 MHz, might read as 1.8:1 at the rig. You think your antenna is fine. It's not.

This isn't academic. I've helped three different hams troubleshoot "the antenna was fine for years" problems that turned out to be failed antenna elements — they just never noticed because their lossy feedline was eating the reflected power.

Measure SWR at the antenna when possible, or at least understand that what your rig shows is the SWR after feedline loss has flattered it.

Key Takeaways

• Match your coax to your frequency and run length — there's no single right answer
• At HF with short runs, don't overthink it. RG-8X gets the job done.
• At VHF/UHF, feedline choice directly impacts your effective radiated power. Spend here.
• Good connectors properly installed and weatherproofed matter as much as cable grade
• When in doubt: LMR-400 with N-type connectors. You won't regret it.