LRM400 vs RG213 coaxial cable

LMR400 vs RG213 are two very good coaxial cables used for high-end radio frequency antennas. These two cables are very similar in size but there are several construction differences. The main difference is that the RG213 coaxial cable is the cheaper of the two and features a stranded bare copper center conductor. Whereas the LMR400 coax cable has a solid bare copper clad aluminum conductor.

The RG213 coax also has a PVC jacket, which is different from the LMR400 coaxial cable that has a PE jacket. Now, these two outer jackets are interesting. PVC vs PE.

Most household applications such as pipes, garden hoses, waterbeds, and vinyl raincoats, typically consist of polyvinyl chloride (PVC). While polyethylene on the other hand is used in bulletproof vests and a variety of other high-temperature products because of its strengths and versatility. So LMR400 uses polyethylene in the construction of its outer jacket which wins for cable protection.

The shielding conductor of these cables is another significant difference that sets LMR400 vs RG213 coaxial cables apart. The RG213 has a single bare copper braid shield, whereas the LMR400 has a double shield which is made of an aluminum braid for the 1st shield and then a braided tinned copper for the 2nd shield. Winner LMR400 again.

LMR400 vs RG213 Specifications

Coaxial SpecificationsRG213LMR400
Conductor TypeStranded (7/0.030)Solid core
Conductor Size (in)0.089 inch0.108 inch
Conductor MaterialBare CopperCopper Clad Aluminum
Dielectric Diameter0.2850.285
Dielectric MaterialSolid Low-Density PolyethyleneFoam Polyethylene
ShieldSingle Bare Copper Braid1st Shield: 100% Aluminum Braid
2nd Shield: Braided Tinned Copper
Overall Diameter (in)0.4050.405
Weight110 lbs/mft
Abbreviation for one thousand
(1,000) feet
68 lbs/mft
Attenuation (signal loss)6.7 dB/100 ft, 22.0 dB/100 m 3.9 dB/100 ft, 12.9 dB/100 m
Our PickFor short cable runs less than 10mOur pick for coaxial cable runs up to 20m.
Shorter the better.

The bellow table shows the Attenuation dB loss of RG213 vs LMR400.

There are different reasons why you may experience a signal loss. The different center conductor cores are the main attenuation factor. The general rule of thumb here is the larger the conductor, the less the attenuation or loss.

Because LMR400 has a larger center conductor than the RG213 cable, the conductor size accounts for the RG213 coaxial cable experiencing more signal loss than the LMR400 cable. Shielding can also play a small part in electrical interference.

FrequencyRG213 Loss (Attenuation dB/100ft)LMR400 Loss (Attenuation dB/100ft)
100 MHz 2.21.2
400 MHz4.82.5
1000 MHz8.24.1

LMR400 Product Performance Parameters at 100 Feet and 915MHz

LMR400 coaxial cable cores and shields
Nominal Attenuation3.9 dB/100 ft, 12.9 dB/100 m
Average Power0.6 kW
Cable Vg85.0%
Nominal Td1.2 ns/ft, 3.9 ns/m
Capacitance23.9 pF/ft, 78.4 pF/m
Typical Connector Loss0.1 dB/pair

LMR400 is used for any application (e.g. WLL, GPS, LMR, WLAN, WISP, WiMax, SCADA, Mobile Antennas) requiring an easily routed,
low loss RF cable.

Cable Assembly Performance

Maximum Cable Assembly Insertion Loss4.4 dB
Cable Run Efficiency40.4%
Cable Run Time Delay119.5 ns

RG213 Product Performance Parameters at 100 Feet and 915MHz

RG213 coaxial cable core
Nominal Attenuation6.7 dB/100 ft, 22.0 dB/100 m
Average Power0.3 kW
Cable Vg66.0%
Nominal Td1.5 ns/ft, 5.1 ns/m
Capacitance30.8 pF/ft, 101.0 pF/m
Typical Connector Loss0.1 dB/pair

RG213 coaxial communication cable is commonly used in UHF radio applications. Suitable for use with radio tower connections and other RF transmitters or receivers. The 50 Ohm impedance has a high power handling capability up to 500v which makes this the coaxial cable of choice in the high-power radio industry.

Cable Assembly Performance

Maximum Cable Assembly Insertion Loss7.4 dB
Cable Run Efficiency21.4%
Cable Run Time Delay153.9 ns

Best Coaxial Cable

LMR400 vs RG213 frequency chart. Higher is better

The chart above shows the losses in decibel dB as the frequency increases for each cable. As you can see the LMR400 has a lower loss all the way up to 3GHz. This is good.

Thus the LMR400 coaxial cable wins in every way. It has a better outer jacket, has a thicker center core, is lighter, has better shielding, and has less loss as the frequency increases. LMR400 has better cable run efficiency and less attenuation or loss over the whole cable run.

This is why I chose LMR400 cable for all of my Helium miner antennas. Just make sure the cable run is as short as possible to reduce attenuation.

I do find that the LMR400 cable is slightly stiffer than the RG213 this is due to the solid center core, and the extra shielding. If you plan your cable run once you make a bend it will stay in shape well. If you are after a very flexible antenna cable then this is not the one for you.

Who makes LMR400 cable?

LMR400 is a high-quality 50-ohm coaxial cable made by the Times Microwave Corporation.

Maximum LMR400 cable run distance

It is recommended to limit the cable run of LMR400 to under 70m (230 ft) This is due to the signal loss over longer distances. LMR400 coax cable will have a dB loss of 0.129 dB per meter. (3.9 dB/100 ft, 12.9 dB/100 m)

What antenna cable for Linxdot helium miners?

Sensecap helium miner using LMR400 cable

For my Sensecap helium miner, I went with the LMR400 antenna cable. This is because I only had a 5m run. For longer runs, LMR600 would be a better choice due to lower signal loss.


If you only have a short 5m coaxial cable run then you won’t see much difference between LMR400 vs RG213. The benefits are much more evident once you start having long cable runs due to signal loss.

As an electrician, I often come across substandard work especially when it comes to home networks and radio frequency cabling. You can’t just run 100m of cheap RG6 cable and expect no losses in the RF signal.

RG6 is ok for TV antennas but if you are running cable for a special project like a Helium miner antenna then the LMR400 coaxial cable is what I use as a minimum standard.

This is why I want to educate people on how to get the best results out of their expensive gear.

Measure out the cable run exactly and get some custom-made LMR400 or above coaxial cable. Or you can make it yourself if you have the special crimpers required for the connections. This way you will minimize your dBi losses and have a better signal-to-noise ratio.

I find that the LMR400 is a good compromise between cost vs performance. If you are serious about your radio frequency gear then don’t skimp out on the cable.

Check out this post if you would like to know more about how to set up a DIY Helium miner using an LMR400 cable.


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