Published on 10/13/2026
LMR-400 generally gives the lowest attenuation of these three standard 50 Ω cable sizes, while LMR-240 and LMR-195 reduce diameter and routing burden. Choose the smallest cable that still meets the actual feeder loss, environmental and connector requirements. A larger cable is not automatically the better assembly.
A 10 m antenna run can justify a larger cable where a 300 mm jumper cannot. At 900 MHz, published typical cable-only loss over 10 m is about 1.28 dB for LMR-400, 2.48 dB for LMR-240 and 3.65 dB for LMR-195. That difference should be compared with the installation effort, not judged by cable names alone.
The figures below refer to the named standard constructions in their published datasheets. Ultra-flex, fire-rated, direct-burial and other variants need their own specifications. SigmaRF can build a cable system to the agreed drawing, but confirm the exact approved cable and connector parts rather than treating similar-diameter products as interchangeable.
On This Page
| Property | LMR-400 | LMR-240 | LMR-195 |
|---|---|---|---|
| Nominal impedance | 50 Ω | 50 Ω | 50 Ω |
| Nominal diameter | 10.29 mm | 6.10 mm | 4.95 mm |
| Velocity factor | 84% | 83% | 80% |
| Nominal delay | 3.92 ns/m | 3.97 ns/m | 4.17 ns/m |
| Inner conductor | Solid copper-clad aluminum | Solid bare copper | Solid bare copper |
| Shield construction | Aluminum tape plus tinned-copper braid | Aluminum tape plus tinned-copper braid | Aluminum tape plus tinned-copper braid |
| Dielectric | Foam PE | Foam PE | Foam PE |
Foam dielectric reduces capacitance and raises propagation velocity compared with many solid-PE miniature cables. That does not create a universal phase-stability rating. Shielding effectiveness, loss and handling remain product and assembly properties; braid coverage alone is not a dB screening test.
Key idea: The comparison is between exact named cable constructions. A cable described as "400 size" or "equivalent" needs its own loss, materials, jacket and connector approval data.
Compare typical attenuation in dB per the same length at the same frequency. The table uses published dB/100 m figures divided by 100. The listed cable-loss conditions are matched VSWR 1.0 and +25 °C ambient, not a maximum guarantee for a connectorized feeder.
| Frequency | LMR-400 dB/m | LMR-240 dB/m | LMR-195 dB/m |
|---|---|---|---|
| 150 MHz | 0.050 | 0.099 | 0.146 |
| 450 MHz | 0.089 | 0.173 | 0.255 |
| 900 MHz | 0.128 | 0.248 | 0.365 |
| 1500 MHz | 0.168 | 0.324 | 0.477 |
| 2500 MHz | 0.222 | 0.424 | 0.624 |
| 5800 MHz | 0.355 | 0.668 | 0.981 |
| 8000 MHz | 0.427 | 0.797 | 1.171 |
At 2.5 GHz, 10 m contributes about 2.22 dB for LMR-400, 4.24 dB for LMR-240 and 6.24 dB for LMR-195. At 5.8 GHz, the same lengths contribute about 3.55, 6.68 and 9.81 dB. Connectors, mismatch, temperature and installation damage can add to the finished-system result.
Use the point matching your radio band, or a manufacturer-supported calculation for that band. The 2.5 GHz row should not silently become a 2.4 GHz guaranteed value. Table endpoints also do not prove that any selected connectorized assembly is qualified to 8 GHz.
Diameter affects enclosure fit, bend space, clamp size and the force applied to a panel connector. Standard LMR-400 is approximately twice the diameter of LMR-195. A large cable hanging off a small device can defeat an otherwise good RF design through mechanical strain.
| Routing check | Published standard examples | Decision |
|---|---|---|
| LMR-400 installation / repeated bend | 25.4 mm / 101.6 mm radius | Do not apply installation radius to repeated movement |
| Cable groups | Different ferrules, contacts and preparation per size | Choose the exact connector variant |
| Jacket versions | Outdoor, general-purpose and fire-rated variants differ | Specify environmental and fire requirements |
| Power tables | Depend on VSWR, temperature, altitude and conditions | Obtain an assembly power/derating basis |
A repeated-bend radius is not a guarantee of unlimited flexing. If a mast, test setup or equipment door moves repeatedly, define the motion and choose the appropriate construction. Stranded ultra-flex versions can differ electrically and mechanically from the standard solid-conductor versions used in this comparison.
⚠️ Peak power, average CW power, dielectric withstand and jacket spark-test voltage are different limits. Never turn one into another or apply cable-only power directly to a connectorized assembly.
Choose LMR-400 when cable loss dominates and its size and routing fit. Choose LMR-240 for a smaller route when its additional loss is acceptable. Choose LMR-195 for short compact links where the loss budget allows it, not as a default long high-frequency feeder.
Antenna feedersWireless equipmentRF jumpersOutdoor links with suitable jacket
Lowest loss priority
For a long route, evaluate LMR-400 first, then check strain relief, connector compatibility and installation geometry.
Compact routing priority
For a short jumper or crowded equipment route, evaluate LMR-240 or LMR-195 and calculate the actual loss penalty.
For a 0.3 m 900 MHz jumper, the cable-only difference between LMR-400 and LMR-195 is about 0.071 dB. That may not justify the larger cable burden. Over 10 m it is 2.37 dB. This is why the best answer changes with length. SigmaRF's cable selection and RF attenuation guides cover the wider cable-family decision.
Specify the complete RF assembly
Send the frequency band, connector interfaces, finished length and routing drawing. SigmaRF can match the cable and terminations to your application.
Step 01
Select the exact cable construction
State the brand/part where required or define the approved alternative and evidence. Specify the jacket version, environment and any fire or burial requirements. Do not assume performance from diameter alone.
Step 02
Select compatible terminations
Define connector family, interface, polarity, angle and cable group. Use the exact stripping and termination instructions. Support heavier cable near the equipment instead of loading a small panel interface.
Step 03
Define assembly acceptance
Give finished length, tolerance and measurement datums, plus VSWR and insertion-loss limits across the operating band. Agree reference planes and fixture handling before comparing reports.
SigmaRF VNA-sweeps every assembly for VSWR and insertion loss before shipment. Its overall RF assembly capability spans 100 MHz to 40 GHz across suitable cable and connector systems, not every product discussed here. Volume work is supported in Vadodara, India, with precision work in the Cleveland area, USA. Lead times can be as short as 2 days for suitable builds, subject to parts, quantity and the agreed specification.
SigmaRF's company-wide 40 GHz capability does not rate these cable assemblies to 40 GHz. The approved cable, connectors and sweep band set the ordered product's limits. Use the RF assembly design and VNA measurement guides for installation reliability and test interpretation.
Assume a 10 m feeder at 900 MHz, with a hypothetical total 0.20 dB connector allowance. Use the published typical cable values; the following is a comparison estimate, not an assembly guarantee. Suppose the target budget is 2.00 dB.
LMR-400: 0.128 x 10 + 0.20 = 1.48 dB
LMR-240: 0.248 x 10 + 0.20 = 2.68 dB
LMR-195: 0.365 x 10 + 0.20 = 3.85 dB
LMR-400 nominal budget margin = 2.00 - 1.48 = 0.52 dB
Matched power ratio for 1.48 dB = 10^(-1.48/10) = 0.711, about 71.1%
Only the largest of these standard examples fits the hypothetical nominal budget. It still needs verification and variation allowance. If it cannot be routed safely, shorten the run, move the radio or investigate another suitable low-loss cable rather than forcing a tight bend into the installation.
Avoid misleading comparisons
Procurement checklist
Is LMR-400 better than LMR-240?
Its standard construction has lower typical attenuation, but is larger at about 10.29 mm versus 6.10 mm. The better choice depends on length, loss budget, routing and connector strain.
What is the difference between LMR-240 and LMR-195?
The standard diameters are about 6.10 mm and 4.95 mm. At 900 MHz their typical cable losses are 0.248 and 0.365 dB/m, respectively. Check exact variants before selecting.
Which cable should I use for a 10 m antenna feeder?
Calculate at the actual band. In the 900 MHz example here, cable-only typical loss is 1.28 dB for LMR-400, 2.48 dB for LMR-240 and 3.65 dB for LMR-195. Add connector and design margin.
Does LMR-400 mean outdoor or direct-burial cable?
The jacket variant matters. Standard outdoor, watertight/direct-burial and fire-rated versions have different designations and approvals. Specify the exact cable and interface sealing.
Can I use the same connectors for all three sizes?
Not by cable-family name. Each size needs an approved connector cable group, ferrule/contact fit and preparation instructions.
Can SigmaRF build a low-loss custom assembly?
Provide the exact approved cable, connector interfaces, length, environment and RF acceptance limits. SigmaRF can agree the build and verification method; confirm part availability and lead time.
LMR-400, LMR-240 and LMR-195 solve different compromises between attenuation and routing. The loss advantage of larger cable grows with frequency and length. In a short jumper, mechanical fit can dominate.
Select the exact variant, compute at the operating band and verify the finished assembly. A clear drawing and test limit are more useful than a blanket recommendation that one size is always best.
Build an RF assembly around the real requirements
Send the frequency band, connector interfaces, finished length and routing drawing. SigmaRF can match the cable and terminations to your application.