Best coax for ham radio
The part of the station nobody photographs and everybody under-buys.
The short answer
For any run over about 50 ft, or anything above 50 MHz at any length, buy LMR-400 class cable. RG-8X is fine for short HF runs where the loss is small in absolute terms. The reason is that 3 dB of feedline loss throws away half your transmit power and half of every signal you try to receive.
- Default choice
- LMR-400 class
- Short HF runs
- RG-8X
- What 3 dB costs
- Half your power
- Worst case
- Thin cable on UHF
- Connector
- PL-259 / UHF
- Rule of thumb
- Buy one grade up
Feedline is the only part of a station that takes something away from every single contact, in both directions, permanently. A radio either works or it does not. An antenna either resonates or it does not. Coax quietly removes a percentage of everything you transmit and everything you receive, for as long as it is installed.
The numbers are not intuitive, which is why people under-buy. 3 dB of loss is half your power gone. On 70 centimetres, 100 ft of thin cable can eat most of what a mobile radio produces. On 40 metres the same cable barely matters. Frequency is what decides whether cheap coax is a sensible economy or a waste of a station.
Everything here is researched from published manufacturer loss specifications rather than from measurements we have taken. Run your own figures on the coax loss calculator.
What loss actually costs you
Loss is quoted in decibels per 100 ft at a stated frequency, and it always rises with frequency. The figure matters because decibels are not linear, and the step from 1 dB to 3 dB is much larger in practice than it sounds.
What a given loss figure means in practice
| Loss | Power reaching the antenna | What it feels like |
|---|---|---|
| 0.5 dB | 89 percent | Nothing you could notice |
| 1 dB | 79 percent | Negligible on receive, invisible on transmit |
| 2 dB | 63 percent | Starting to matter on marginal signals |
| 3 dB | 50 percent | Half your power. One S-unit is about 6 dB. |
| 6 dB | 25 percent | A full S-unit. A 100 W radio behaving like 25 W. |
| 10 dB | 10 percent | The feedline is now the station |
Receive is affected identically, which people forget. A feedline that halves your transmit power also halves every signal arriving.
Which cable, by band and length
Two variables decide everything: how long the run is and how high the frequency is. A short HF run forgives almost any cable. A long UHF run forgives nothing.
- HF up to about 50 ft: RG-8X is genuinely fine. Loss at 14 MHz is small enough that the money is better spent on the antenna.
- HF over 50 ft, or any VHF: move to LMR-400 class. This is where the cheap cable starts costing you real signal.
- UHF at any meaningful length: LMR-400 class minimum, and shorten the run if you can. 70 centimetres punishes thin cable badly.
- Never use RG-58 for a permanent outdoor run. It is a patch cable, and its loss on VHF is poor.
- Buy one grade heavier than you think you need. Nobody has ever regretted better coax; plenty of people have re-pulled a run.
Three tiers
Three cables that cover almost everything
By run length and band rather than by price.
A first HF station with the antenna close to the shack
STEREN
STEREN RG-8X coax 50 ft with PL-259
Thinner, cheaper and much more flexible than LMR-400, which matters when you are routing through a window frame or around a corner. At HF over a short distance the extra loss is small in absolute terms.
- Length 50 ft
- Type RG-8X
Tradeoff
Loss climbs steeply with frequency. Do not use this for VHF or UHF, and do not use it for a long run at any band.
Almost every station, and every VHF or UHF station
MOOKEERF
MOOKEERF 50 ft KMR400 coax with PL-259 ends
Low enough loss that feedline stops being a variable you have to think about. Factory-fitted PL-259 ends remove the most common failure point in a home-built feedline, which is a poorly soldered connector.
- Length 50 ft
- Class LMR-400
Tradeoff
Stiff. It does not like tight bends, and it needs a proper entry route rather than being squeezed under a sash.
Anyone with a tuner, a meter or an amplifier in the chain
MOOKEERF
MOOKEERF RG-8X 3 ft jumper, 2 pack
Three foot jumpers for radio to tuner to meter. The alternative is coiling a spare 50 ft run behind the desk, which is untidy and adds loss for no reason.
- Length 3 ft
- Quantity 2 pack
Tradeoff
Each extra connector pair adds a small loss and one more thing to work loose. Use as few as the layout needs.
Connectors, and the one that is misnamed
- PL-259, confusingly called a UHF connector, is the HF and VHF standard despite the name. It is not a constant-impedance design and is genuinely poor above about 300 MHz.
- Type N is the correct choice for UHF and above, and it is weatherproof when assembled properly.
- BNC is for test gear and patch leads, not for a feedline carrying power.
- Weatherproof every outdoor joint. Water ingress turns a good cable into a bad one permanently, and the failure is gradual enough that people blame the antenna.
- Full detail on the coax connector chart.
How to choose in one pass
Four questions
- 1
How long is the run, really?
Measure the path the cable will take, not the straight line. Add slack for a drip loop and for service. People routinely under-measure by 20 percent.
- 2
What is the highest band you will use?
Size the cable for that, not for your current favourite band. Feedline is not something you want to replace when you add 70 centimetres.
- 3
Run the numbers
Put length, type and frequency into the coax loss calculator. If the answer is over about 2 dB, go one grade heavier.
- 4
Decide about connectors
Factory-fitted ends for anything you are not confident soldering. A bad PL-259 joint is a common and hard-to-find fault.
Common questions
Questions people ask about this
Is LMR-400 worth it for HF?
For runs over about 50 ft, yes. For a 25 ft run on 40 metres the difference against RG-8X is a fraction of a decibel and completely undetectable, so the money is better spent on the antenna or on getting it higher. The reason to buy LMR-400 anyway is future proofing: if you ever add VHF or UHF, or move the antenna further away, the cable is already right.
Can I use RG-58 for my antenna?
Not for a permanent run. RG-58 is a patch cable. Its loss on VHF is poor and on UHF it is bad enough that a mobile radio can lose most of its output in 100 ft. It is acceptable for a short jumper on the bench and nothing else.
Does coax loss affect receiving as well as transmitting?
Yes, identically, and this is the part people miss. Feedline is passive and symmetrical, so a cable that halves your transmit power also halves every signal arriving from the antenna. On a quiet band that is the difference between hearing a station and not.
Do I need to solder my own connectors?
No, and unless you are confident, factory-fitted ends are the better choice. A poorly soldered PL-259 is one of the most common faults in a home station and one of the most annoying to diagnose, because it often works at low power and fails intermittently at higher power.
How long does coax last outdoors?
Good cable with properly weatherproofed connectors lasts many years. The usual failure is water ingress at a joint rather than the cable itself degrading, and it happens gradually, so performance falls off slowly enough that people blame the antenna or the radio. Seal every outdoor joint and inspect them when you next have the antenna down.
Keep going
Related on this site
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Disclaimer Researched guidance for planning purposes, not professional engineering, electrical or legal advice. Antenna work, RF exposure, mast and tower work, grounding and battery handling all carry real risk that depends on your specific site and installation. Verify anything safety-critical against current FCC rules, the National Electrical Code and the manufacturer's own documentation, and hire a professional where the job calls for one. We research equipment from published specifications, regulatory documents and verified owner reviews rather than claiming hands-on testing we have not done.