Every foot of coax between your radio and your antenna quietly takes a bite out of your signal, both on transmit and receive. Pick the wrong cable for the job and you can lose a meaningful chunk of your power before it ever reaches the antenna, and lose weak signals before they ever reach your receiver. Pick the right one and that loss becomes small enough to ignore. This guide compares the coax types most hams actually run — RG-58, RG-8X, RG-213, and the LMR series — so you can match cable to your bands, your run length, and your budget.
What "Loss Per 100 Feet" Actually Means
Coax loss is usually published as decibels of attenuation per 100 feet at a given frequency, and it isn't a fixed number — it rises with frequency and adds up with length. A cable that barely matters on 80 meters can become a real liability on 2 meters or 70 centimeters. Loss is also cumulative in a straightforward way: double the cable length and you roughly double the loss in dB. That's why a "good enough" cable for a short run to a nearby vertical can be a poor choice for a run of 100 feet or more out to a tower.
The Common Coax Types You'll See
Most amateur stations end up choosing between a handful of well-known 50-ohm cables:
- RG-58 — thin, flexible, inexpensive, and common on handheld accessories and short jumpers. Loss is high enough that it's a poor choice for any serious run.
- RG-8X (often called "mini-8") — a step up in size and loss performance while staying flexible and easy to route through tight spaces.
- RG-213 (and similar RG-8 types) — a thicker, general-purpose cable that has been a station staple for decades, with meaningfully lower loss than RG-8X.
- LMR-400 — a low-loss cable in roughly the same outer diameter as RG-213, but built with a solid center conductor and better shielding, giving noticeably lower loss at the same size.
- LMR-600 and larger — thicker still, lower loss again, at the cost of flexibility, weight, and a bigger bend radius.
If you're shopping around, the ham radio marketplace is a good place to compare what other operators are selling or looking for, including pre-made feedline runs with connectors already installed.
Approximate Loss Figures Worth Knowing
Manufacturer-published loss figures vary a bit by brand and cable quality, so treat these as rough, illustrative values rather than exact specs — but the relative ordering holds true across the board. At 28 MHz (10 meters), RG-58 typically loses somewhere around 2 to 2.5 dB per 100 feet, RG-8X around 1.5 to 1.8 dB, RG-213 under 1 dB, and LMR-400 a bit less again. Move up to 2 meters or 70 centimeters and the gaps widen considerably — thin cable that was tolerable on HF can lose a third or more of your power over a long VHF/UHF run.
Power Handling: Usually Not the Deciding Factor
Power ratings get a lot of attention, but for most stations running 100 watts or less, power handling isn't really the limiting factor — any of these cables, kept reasonably short, can handle that comfortably. Power handling and loss are related, though: the loss in a cable shows up as heat, so a thinner, higher-loss cable reaches its thermal limit at a lower power level than a thicker, lower-loss one. If you're running an amplifier at legal limit, especially into a long run, that's when cable size and quality start to matter for power handling as well as for signal loss.
Matching Cable to Your Run Length
Short runs forgive a lot. A 25 or 30 foot jumper of RG-8X from the radio to an antenna tuner, or from a tuner to a nearby vertical, will lose very little signal on any band. The picture changes once you're running 75, 100, or 150 feet out to a tower or a remote antenna location — at that point the difference between RG-8X and LMR-400 can be the difference between a solid signal and a noticeably weaker one. This is the same logic that applies if your shack is physically separated from your antenna system, including setups built around Remote Rig where the feedline run to the actual antenna deserves the same careful sizing as any fixed station.
HF vs. VHF/UHF: Different Priorities
On the lower HF bands, loss differences between cable types are real but often small in absolute terms over typical station runs, so a mid-grade cable like RG-8X is often perfectly adequate for moderate distances. On VHF and UHF — repeater work, satellites, weak-signal operating — loss per foot climbs sharply with frequency, and low-loss cable like LMR-400 or better starts to matter a lot more, even over shorter runs. If you're not sure which band your run will spend the most time on, check the quick reference page for a refresher on where your bands of interest fall, and size your cable toward the higher end of what you actually operate.
Connectors and Cable Size Go Together
Cable choice and connector choice aren't independent decisions. Standard PL-259/SO-239 connectors were designed around RG-213-sized cable and solder easily onto it; using them on RG-8X requires a reducer, and using them on LMR-400 typically means a connector made specifically for that cable's solid center conductor, since ordinary PL-259s don't crimp or solder onto it cleanly. Type N connectors handle weather better and perform more consistently at VHF/UHF, which is worth considering for any outdoor connection exposed to the elements. Whichever you choose, weatherproof every outdoor connector with quality tape or self-fusing silicone tape, and never leave a bare metal joint exposed to rain and sun.
Common Mistakes to Avoid
- Choosing by price alone. The cheapest cable per foot is often the highest-loss cable per foot too — factor in your actual run length before deciding.
- Using RG-58 for a long HF run. It's fine for a short jumper, but a poor choice once you're past 25 or 30 feet.
- Mismatching connectors to cable size. A PL-259 forced onto the wrong cable diameter is a common source of intermittent connections.
- Skipping weatherproofing. Water intrusion at an outdoor connector raises loss and SWR gradually, which can be hard to diagnose later.
- Coiling excess cable too tightly. Sharp bends, especially in stiffer low-loss cable, can damage the shield or center conductor over time.
- Assuming loss doesn't matter at 100 watts. It still reduces both your transmitted signal and your received signal, especially on weak-signal work.
If a cable problem is masquerading as an antenna problem, it's worth reading our guide to what SWR really tells you, since a bad connector or damaged cable can produce readings that look like an antenna issue.
A Quick Coax Checklist
- Know your run length before you buy — measure the actual path, not a straight-line guess.
- Identify your primary bands, since VHF/UHF punishes thin cable much more than HF does.
- For runs under about 30 feet on HF, RG-8X is usually adequate.
- For longer HF runs, or any serious VHF/UHF distance, step up to RG-213 or LMR-400.
- Match your connectors to your cable size rather than forcing a fit.
- Weatherproof every outdoor connection, every time.
- Avoid tight coils and sharp bends, especially near connectors.
Wrap-Up
There's no single "best" coax — there's the right cable for your bands, your run length, and how much flexibility and cost you're willing to trade for lower loss. For most home stations, that means RG-8X for short runs, RG-213 or LMR-400 for longer ones, and a step up to LMR-600 only when the run gets long or the frequency gets high. If you're still working out the rest of your antenna system, our beginner's guide to choosing an HF antenna and our comparison of coax and ladder line are good next reads. And if a question comes up that this article didn't answer, the ham radio FAQ is a solid place to check next.
How HamRadioList can help
Once your feedline is sorted, check the {{svc:propagation|live HF propagation page}} before your next session and log the contacts that follow in the free {{svc:logbook|online logbook}}. If you're weighing radios or cable for a remote setup, {{svc:remote_rig|Remote Rig}} is worth a look too.
- Ham radio marketplace - buy and sell radios, antennas and accessories.
- Ham radio quick reference - bands, modes, phonetics and Q-codes on one page.
- Remote Rig - operate your own radio from anywhere on Android, iPhone, Windows or Linux, with live push-to-talk audio and CAT control.
- Ham radio FAQ - plain answers to the questions new operators ask most.
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