Antenna cable loss comparison is not a minor installation detail when a LoRaWAN gateway is expected to serve meters, sensors, and field assets across a large area. A cable that looks economical on a purchasing sheet can remove several decibels from the RF path before the signal ever reaches the antenna. That loss directly reduces the link margin available for difficult indoor devices, low-mounted sensors, and nodes operating at the edge of coverage.
For a short indoor jumper, almost any suitable 50-ohm coax may be acceptable. For a rooftop antenna, a tower-mounted gateway, or a distributed industrial site, cable choice deserves the same attention as gateway placement and antenna gain. The objective is simple: put the antenna where it has a clear RF view, then use the lowest-loss practical cable to connect it without creating unnecessary installation or budget burden.
Why cable loss changes LoRaWAN coverage
Coaxial cable attenuates RF energy. On the gateway transmit path, attenuation means less power reaches the antenna. On the receive path, it means the already weak signal from an end device arrives at the gateway radio at a lower level. The same cable loss affects both directions.
Loss is measured in decibels (dB). A 3 dB loss is significant because it represents roughly half the RF power. A 6 dB loss leaves about one-quarter of the original power. LoRaWAN can often decode very weak signals because of its modulation and spreading-factor options, but that sensitivity should not be treated as spare capacity to waste. Link margin is what helps a network remain reliable through building penetration, foliage, seasonal changes, rain, interference, and antenna pattern imperfections.
A gateway with a well-sited external antenna may gain far more from using a better cable than from choosing a higher-gain antenna at the end of a long, lossy run. Height, clearance, and cable loss must be evaluated together.
Antenna cable loss comparison at 915 MHz
For US LoRaWAN deployments, cable specifications should be reviewed close to the 902-928 MHz operating range. Published figures vary by manufacturer, conductor type, jacket construction, and test frequency, so the values below are planning estimates rather than final specifications. Always use the attenuation data for the exact cable being purchased.
| Cable type | Typical loss at about 915 MHz per 100 ft | Best-fit use case |
|---|---:|---|
| RG-174 or similar miniature coax | 20-25 dB | Very short internal or enclosure connections only |
| RG-58 | 10-12 dB | Short indoor jumpers where flexibility matters |
| LMR-195 class | 7-8 dB | Short gateway-to-antenna runs |
| LMR-240 class | 5-6 dB | Moderate runs with limited routing space |
| LMR-400 class | 3.5-4.5 dB | Rooftops, poles, and standard outdoor gateway installations |
| LMR-600 class | 2.5-3 dB | Long feeder runs where lower loss justifies cable size |
| 1/2-inch hardline | 1.5-2.5 dB | Permanent long runs and high-reliability infrastructure |
The difference becomes clearer when cable length is applied. At 30 feet, an LMR-195 class cable may introduce roughly 2.2 dB of loss, while an LMR-400 class cable may be closer to 1.2 dB. That one-decibel difference can be worthwhile, but it may not justify a difficult installation in every location.
At 100 feet, the decision is more consequential. LMR-195 class cable can approach 7 to 8 dB of loss before connectors are counted. LMR-400 class cable may be around 4 dB, preserving roughly 3 to 4 dB of additional link budget. In a network supporting hard-to-reach utility meters or industrial sensors inside metal-adjacent spaces, that margin can materially improve packet reception.
Start with the cable length, not the catalog
The most effective way to control loss is to shorten the run. If a gateway can be installed in a protected location near the antenna, a 10-foot outdoor-rated cable may be a better design than placing the gateway in a distant communications room and running 100 feet of premium coax. This approach also reduces connector count, grounding complexity, and installation labor.
That said, gateway placement involves more than RF. The enclosure location must support power, Ethernet or cellular backhaul, environmental protection, physical access, and maintenance. In many deployments, the right answer is an outdoor-rated gateway or enclosure mounted close to the antenna, with PoE or a suitable backhaul extension serving the site infrastructure.
When the gateway must remain indoors, measure the actual routing path. Include vertical rises, service loops, conduit transitions, and the distance needed to create proper bend radii. A nominal 50-foot route often becomes 65 or 70 feet once the installation is built correctly.
Account for connectors, arrestors, and adapters
Cable specifications alone do not represent total RF path loss. Every component between the gateway radio port and antenna contributes insertion loss. A properly installed connector may add only a small fraction of a decibel, but multiple connectors, adapters, surge protectors, and bulkhead fittings accumulate.
A typical outdoor path may include a gateway connector, a short jumper, a lightning arrestor, a feeder cable, and an antenna connector. The total additional loss may be modest, but it should be included in a design where the RF budget is tight. Poorly terminated connectors are a larger concern than their nominal insertion loss. Water ingress, loose interfaces, incorrect connector gender, or a damaged center pin can create intermittent performance that is difficult to diagnose remotely.
Use 50-ohm components throughout the gateway-to-antenna path. Avoid consumer television coax, 75-ohm splitters, and low-cost adapters not rated for the operating band. For outdoor installations, select connectors and cable assemblies designed for weather exposure, then protect mating points with appropriate weather sealing practices.
Cable size brings trade-offs
Lower-loss coax is generally thicker, heavier, stiffer, and more expensive. LMR-400 class cable is a common practical choice for many LoRaWAN gateway installations because it offers substantially lower loss than small flexible coax without the routing challenges of very large feeder cable.
LMR-600 class cable and hardline can be justified for long runs, elevated antenna systems, and coverage-critical infrastructure. They are less convenient in crowded equipment cabinets, tight conduit, and compact wall penetrations. Their bend radius and support requirements must be planned before purchase.
A short flexible jumper still has a role. It can relieve mechanical strain at a gateway port or simplify service access, provided its length remains minimal. The design principle is to use flexible cable only where flexibility is needed and low-loss feeder cable for the distance that matters.
Evaluate the full RF path, including antenna gain
Antenna gain does not automatically compensate for cable loss. A higher-gain omnidirectional antenna typically compresses its vertical coverage pattern to concentrate energy toward the horizon. That can be beneficial for a flat municipal area or a wide industrial campus, but it can reduce performance for sensors directly below a high-mounted antenna or across varying terrain.
For example, replacing a 3 dBi antenna with an 8 dBi antenna may appear to add 5 dB. If that upgrade also requires an extra 100 feet of small coax with 8 dB of loss, the system has moved backward before connector losses are included. A lower-gain antenna placed higher and connected with a short LMR-400 class run may provide more dependable real-world coverage.
Gateway output limits and local regulatory requirements also matter. The final effective radiated power must be evaluated as a system, considering radio output, cable loss, antenna gain, and installation configuration. This is especially relevant for private networks using external antennas selected to extend coverage across large facilities or communities.
A practical selection approach
For a short indoor run under 20 feet, a quality LMR-195 or LMR-240 class cable is usually a sensible balance of loss, flexibility, and cost. For a rooftop or pole-mounted antenna with a run of 25 to 75 feet, LMR-400 class cable is often the preferred baseline. Beyond that range, assess LMR-600 class cable, hardline, or a design that moves the gateway closer to the antenna.
Before finalizing a bill of materials, calculate the total expected loss at the actual LoRaWAN frequency, add connector and protection-device loss, and compare the result with the intended coverage objective. Then validate the design with field measurements after installation. Uplink packet success rates, RSSI, SNR, and device distribution maps will show whether the planned link margin translates into usable coverage.
LoRaWorld supports infrastructure buyers who need to align gateways, antennas, cable assemblies, and deployment requirements rather than select each component in isolation. The right cable is rarely the most expensive option. It is the one that preserves the RF performance your site needs while remaining practical to install, protect, and maintain over the life of the network.