KMR400 UHF Coax Cable 50ft PL-259 - Low Loss Coax for HAM & CB

In this review the 50ft KMR400 UHF coax jumper with PL-259 UHF male connectors is evaluated for HAM, CB and marine use; the bottom line is simple: it is a purpose-built, low-loss coax that targets operators who need reliable outdoor runs and minimal signal attenuation. Tested on network analyzers during production to assure a VSWR under 1.35 and built with a 100% shield braid, the cable delivers the kind of consistent performance that matters for antenna analyzers, SWR meters and AIS or marine radio installations.

Key Features

• Low loss construction: The KMR400 design and high-density tinned copper braid keep signal loss very low, measured at around 0.26db for a 3ft segment at 500MHz, which preserves RF performance over longer runs.
• Professional manufacture: Swept with network analyzers during production to maintain VSWR below 1.35, ensuring predictable match quality for sensitive radio and analyzer work.
• Robust connector attachment: Uses a heavy PL-259 mount clamp connector rather than a crimp type, reducing the chance of separation under strain or outdoor exposure.
• Durable materials: Copper clad aluminum conductor plus a UV-proof RF-PVC jacket are specified for long outdoor life, aimed at up to 20 years of exposure in harsh environments.
• Waterproof sealing: Comes with nickel-plated UHF connectors and an adhesive-lined heat shrink tube up to 2.2 in long to create sealed end connections for marine and exterior use.

Who It's For

This cable suits HAM and CB operators who need a low-loss, weatherproof jumper for fixed antenna installations, marine radio, AIS or when running to an SWR meter or antenna analyzer. Users who prioritize a secure PL-259 attachment and predictable VSWR during tuning will appreciate the factory swept assurance.

It is less ideal for installers who need the absolute maximum flexibility in tight routing, as customers report mixed impressions of stiffness; those requiring tiny bend radii or the lightest, most flexible RG-style cable might look elsewhere.

Pros & Cons

Pros

• Low insertion loss and full braid shielding preserve signal for HF/VHF/UHF work.
• Sturdy PL-259 mount clamp connectors and adhesive-lined heat shrink provide durable, sealed terminations for outdoor use.
• Manufactured with production sweeps to keep VSWR under control for accurate analyzer and SWR meter readings.
• UV-proof jacket and nickel-plated connectors increase longevity in marine environments.

Cons

• Some users find the cable stiffer than expected, so routing in very tight spaces can be more difficult than with thinner coax.

Specifications

Length	50 ft
Connector type	PL-259 UHF male
Impedance	50 ohm
Shield	High-density tinned copper, 100% shield
Conductor	Copper clad aluminum
Jacket	UV-proof RF-PVC
VSWR (production)	Less than 1.35 (swept)

Our Verdict

The 50ft KMR400 PL-259 UHF coax is a strong choice for HAM, CB and marine installations where low loss and a secure, weatherproof connection matter. It balances durability and RF performance at a good value, especially for fixed runs and analyzer work; choose a more flexible cable only if tight routing is the primary concern.

Frequently Asked Questions

Is this cable suitable for marine use?
Yes, the UV-proof jacket, nickel-plated connectors and adhesive-lined heat shrink are intended to provide sealed end connections and long outdoor life for marine installations.

How much loss does the cable introduce?
Production data cites very low loss; a 3 ft sample shows about 0.26db at 500 MHz and customers report similarly low loss at VHF/UHF frequencies.

Are the connectors reliably attached?
Yes, the product uses a heavy PL-259 mount clamp connector rather than a crimp type, reducing the chance of the connector coming off under use.