Published on 10/13/2026
You are choosing between RG316, RG58 and LMR-240 for a 2.4 GHz run and want the loss numbers on one page, not scattered across seven datasheets. This chart gives approximate attenuation in dB per meter for the common RG and LMR cables at eight frequencies from 100 MHz to 10 GHz.
Short answer: loss rises with the square root of frequency and falls as the cable gets larger. At 2.4 GHz, RG174 loses about 1.7 dB/m, RG316 about 1.4, RG58 about 1.2, LMR-240 about 0.6 and LMR-400 about 0.35.
Values are typical planning figures. Individual makers differ by 10 to 20 percent, so confirm against the datasheet of the exact cable before you finalize a link budget.
On This Page
| Cable | 100 MHz | 400 MHz | 1 GHz | 2.4 GHz | 3 GHz | 5.8 GHz | 8 GHz | 10 GHz |
|---|---|---|---|---|---|---|---|---|
| RG174 | 0.30 | 0.60 | 1.05 | 1.7 | 1.9 | 2.7 | 3.1 | 3.4 |
| RG316 | 0.30 | 0.55 | 0.90 | 1.4 | 1.6 | 2.2 | 2.6 | 3.0 |
| RG58 | 0.16 | 0.37 | 0.72 | 1.2 | 1.3 | 1.9 | 2.2 | 2.5 |
| RG213 | 0.10 | 0.23 | 0.45 | 0.74 | 0.82 | 1.15 | 1.35 | 1.5 |
| LMR-195 class | 0.17 | 0.34 | 0.55 | 0.8 | 0.9 | 1.3 | 1.5 | 1.7 |
| LMR-240 class | 0.12 | 0.24 | 0.38 | 0.60 | 0.67 | 0.95 | 1.1 | 1.25 |
| LMR-400 class | 0.07 | 0.14 | 0.22 | 0.36 | 0.40 | 0.58 | 0.68 | 0.76 |
Amber values are above the frequency where the cable is normally rated or the connectors are practical. They are shown for comparison, not as a recommendation. To convert dB per meter to dB per 100 ft, multiply by 30.48.
Step 01
Pick the frequency column
Use the highest frequency in your band, not the center.
Step 02
Multiply by length
Loss in dB is the dB per meter value times the length in meters.
Step 03
Add connectors
Add 0.1 to 0.2 dB per connector pair for SMA, N and BNC at these frequencies.
Step 04
Add margin
Add 10 percent for aging, bends and manufacturing spread.
Get the right cable for your frequency
Send frequency, length and connectors. We will recommend and build the assembly, with every unit swept on a VNA for VSWR and insertion loss.
Talk to an EngineerBetween table points, scale by the square root of the frequency ratio. If a cable loses 1.4 dB/m at 2.4 GHz, expect about 1.4 x sqrt(5.0 / 2.4) = 2.0 dB/m at 5.0 GHz. This is accurate to about 10 percent for solid-dielectric cables, and slightly low at high frequency where dielectric loss grows.
Key idea: Doubling the cable diameter roughly halves the loss. That is why LMR-400 has about a third of the loss of RG58, at the cost of a stiffer 10.3 mm cable.
| Need | Good choice | Why |
|---|---|---|
| Short internal jumper, flexible | RG316 or RG178 | Small, PTFE, handles heat |
| General lab and antenna runs to 1 m | RG316 or RG58 | Common, easy connectors |
| Runs of 3 to 10 m at UHF or 2.4 GHz | LMR-240 class | Good loss for 6 mm size |
| Long outdoor runs | LMR-400 class or RG213 | Lowest loss, outdoor rated |
| 18 GHz and above | Semi-rigid or microwave flex | Not RG58 or RG316 |
For the single-case loss calculation, see the loss calculator guide in this series. For RG316 at high frequency, see the RG316 maximum frequency article.
Avoid
What is the attenuation of RG58 at 2.4 GHz?
About 1.2 dB per meter, so 5 m costs about 6 dB.
Which coax has the lowest loss?
Larger cable has lower loss. LMR-400 class loses about 0.36 dB/m at 2.4 GHz, compared to 1.4 dB/m for RG316.
How much does RG316 lose at 5.8 GHz?
About 2.2 dB per meter.
How do I convert dB per 100 ft to dB per meter?
Divide by 30.48.
Does loss depend on cable length linearly?
Yes. Loss in dB is proportional to length.
Are these values exact?
No. They are typical planning values; makers differ by 10 to 20 percent.
Use the chart to compare cables at the same frequency, multiply by length, and add connectors and margin. If the number is more than your budget allows, step up the cable size or shorten the run.
SigmaRF builds assemblies on RG174, RG316, RG58, RG213 and low-loss cable in India (Vadodara) and the USA (Cleveland area), VNA-swept before shipment, with lead times as short as 2 days.
Build the cable you picked
Standard or custom, swept before shipment.
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