Understanding Coaxial Cable Terms: LMR. RFC, CFD, Oh My!

September 09, 2021

If you are in the market for a coaxial cable for your Helium miner or ALFA Network WiFi booster, it seems to be a confusing world of letters and numbers. What do they mean? For the most common types of low loss cables such as 195, 200, 240, and 400, this indicates the thickness of the shielding (aka grade), and correlates to how low loss it is.

200 grade cable is .200 of an inch thick, or 2/10ths of an inch, and thus has more dB loss than a 400 grade cable, which is 4/10ths (.400) of an inch thick, almost half an inch. 

We carry mostly 240, 400, and 600 grade options. 240 is suitable for shorter cables and pigtails, while 400 is recommended for longer length. Going 75 feet or above, 600 grade may be the best choice.

But what about the letters? Is there a difference between LMR and RFC? These letters indicate the brand. LMR is a trademark of Times Microwave, whereas RFC is made by Shireen. According to specs by each company, their shielding is equivalent in terms of dB loss, so this is why RFC-400 and other XXX-400 brands are often referred to as "LMR equivalent."

Are the cables 100% identical? No, each manufacturer has their own processes and quality control procedures. Think of car tire brands. If you shop for tires, you will find different brand tires that fit your wheels with identical tread depth and other similar specs, but they are not identical tires. 

We find LMR, RFC, and CFD to be great brands in our own testing, and RFC specifically to offer the best overall value. But all are great cables. If you are looking at other off brands, they may be OK, but if they do not adhere to high manufacturing and quality control standards, they may come apart after a few uses, and you may spend more money in the long term replacing cables and dealing with down time.

We do not recommend lower grade shielding like RG174 for longer lengths, as the dB loss will be too much and performance will suffer.

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