RG8x vs RG213 Coax | Choosing The Right Cable

Choosing between RG8X and RG213 coax means balancing signal loss, power handling, and physical flexibility against your actual installation. The right cable for a 150-foot tower run is different from the right cable for a portable base station where the coax bends around desks and equipment racks. Here is what each cable does well and where you want the other one instead.

How Do RG8X and RG213 Compare on Loss and Power?

The biggest difference between these two 50-ohm coax cables is size. That extra conductor mass gives RG213 much lower attenuation and much higher voltage and power ratings.

At 100 MHz, a 100-foot run of RG8X loses about 4.7 dB of signal, whereas RG213 loses only 2.8 dB — roughly half the loss. The gap widens at higher frequencies. At 1,000 MHz, RG8X loses 15.4 dB per 100 feet against RG213’s 10.1 dB. Power handling follows the same pattern: RG8X is rated for roughly 1,000 watts on HF, while RG213 can handle up to 1,800 watts at 30 MHz and 1,200 watts at 50 MHz.

Which Coax Cable Should You Choose?

For any run longer than 50 feet, RG213 is almost always the right call. The lower attenuation means more of your transmitter’s power actually reaches the antenna, and the higher voltage and power ratings give you a comfortable safety margin with most HF, VHF, and UHF radios. RG213 is also mechanically tougher for outdoor installations and long-term exposure to weather.

RG8X shines in the opposite scenario: runs under 50 feet where signal loss is negligible, portable setups where every ounce and inch matters, and any installation that requires tight bends around corners or through narrow spaces. Its 0.242-inch diameter is noticeably easier to route than RG213’s stiff 0.405-inch jacket. For a typical ham radio base station with short jumper cables or a mobile setup, RG8X is perfectly adequate and much easier to work with.

A common mistake is confusing RG8 with RG8X. Standard RG8/U has the same 0.405-inch diameter as RG213 but with higher loss, while RG8X is the thinner, more flexible mini version. If you are setting up a CB radio station and need a longer feed line, our roundup of top-rated coax cables for CB use will help you pick the right one — the correct choice depends on your power level and run distance. The W4RP coax performance reference provides detailed loss figures across frequencies for both cables.

If you run a high-power transmitter above 500 watts or plan to operate on VHF or UHF bands, skip RG8X and go straight to RG213. The connector types differ too — RG8X uses smaller connectors, often PL-259 adapted for mini-coax, while RG213 takes standard PL-259 connectors. Plan your connector purchases accordingly.