RG178 vs RG316 | Product Knockout

Product_KnockoutOur Product Knock-out series is a match-up between two similar products. In boxing terms, think same weight class, same caliber, and same level of experience and amount of exposure. The purpose of these posts are for you to see a side-by-side view of two similar products, and understand which one will be crowned champ for your specific purposes. Take your seats and prepare for battle, because the gloves are coming out.

RG178 and RG316 are high temperature, high performance coaxial cables. These cables are manufactured in accordance with the MIL-DTL-17 specs, and are designed for use in high temperature applications, among many others. RG178 coax cable and RG316 coax cable can be used in radio frequency applications, wireless communication, broadcast equipment, and in direct burial. These cables are very similar, but what sets them apart? Let’s find out.

RG178 vs RG316 Specs for Construction
RG178 RG316
Conductor Type Stranded (7/.004) Stranded (7/.0067)
Conductor Diameter 0.012” 0.020”
Conductor Material Silver-coated Copper Clad Steel Silver-coated Copper Clad Steel
Dielectric Diameter 0.033” 0.060”
Dielectric Material PTFE PTFE
Shield/Outer Conductor Silver Plated Copper Braid Silver Plated Copper Braid
Jacket FEP FEP
Overall Diameter 0.071” 0.098”
Weight (lbs/mft) 6.3 9.89

Both RG178 and RG316 feature stranded, silver-coated copper clad steel conductors, the same PTFE dielectric material, the same silver plated copper braid shield, and the same FEP jacket.

So, what stands out the most in the construction of these two cables? The size.

The size of these cables vary right from the center of each cable, starting with the conductor diameters. Having a larger conductor also contributes to the weight of the cable.

From the numbers in the table, you can see that RG-316 is almost double the size of RG-178, especially when comparing the dielectric diameter of both cables.

RG178 vs RG316 Electrical Specs
RG178 RG316
Min. Temperature Rating -55°C -55°C
Max. Temperature Rating 200°C 200°C
Max. Voltage 1000 900
Impedance (ohms) 50 +/-2 50
Capacitance (pF/ft) 29.4 32

The electrical specs between RG 178 coax and RG 316 coax are fairly similar. They both have the same minimum and maximum temperature ratings, similar impedance, but they vary slightly in voltage rating and capacitance.

RG178 Loss (Attenuation dB/100ft) RG316 Loss (Attenuation dB/100ft)
Typical Attenuation Max. Attenuation Typical Attenuation Max. Attenuation
100 MHz 14.7 16.0 7.8 11.0
400 MHz 30.2 33.0 16.0 21.0
1 GHz 48.9 52.0 26.3 38.0
2.4 GHz 78.7 83.3 43.0 55.4

Because RG178 and RG316 both have silver-coated copper clad steel conductors, the difference in attenuation between the cables cannot be blamed on conductor material. In fact, these cables are so similar that it may be surprising that RG178 experiences almost twice as much attenuation as RG316.

In this case, it comes down to conductor size. RG 178 is smaller than RG 316, and it experiences more loss because of its size. RG 316 has less loss because the conductor is larger. Typically, the larger the conductor, the less loss a cable experiences.

RG178 vs RG316 Cable

RG178 vs RG316 Cable

Winner by unanimous vote? Instead, it seems as if the match has ended in a technical decision. In this case it looks like our crowned champ depends on your specific application use.

If you are unsure about what coaxial cable you’ll need in order to meet the needs of your application, consult with a qualified engineer or with one of Allied’s knowledgeable sales reps. To learn more about RG178 and RG316 visit the coaxial cable main product page.

About awcwire
Allied Wire & Cable is a value-added manufacturer and distributor of electrical wire and cable, tubing, and more. We are a family owned and operated company, serving a wide range of industries, including the military, automotive, aerospace, and telecommunications markets. Allied is headquartered in Collegeville, PA. Additional locations can be found across the US, in Merrimack, NH, Tampa, FL, Pewaukee, WI, and Las Vegas, NV. For more information on Allied, visit our main website at www.awcwire.com.

3 Responses to RG178 vs RG316 | Product Knockout



    Swap the positions of the two cable photos, so that RG-178 is on the left and RG-316 is on the right.

  2. Elwood Downey says:

    I do not understand the weight. What is “mft”? “m” is normally milli or 1/1000 but that makes no sense here.

    • awcwire says:

      Hi Elwood,

      W = Weight of one shielding strand (Lbs./Mft.) W = Weight of one insulated conductor (Lbs./Mft.)

      Hope that helps:-)

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