Selecting the proper coaxial cable is an important part of building an efficient amateur radio station. Different cable types exhibit different amounts of signal loss, known as attenuation, which increases as frequency rises.

The chart below compares several common coaxial cable types and their approximate signal loss in decibels (dB) per 100 feet at various frequencies.  

Why Coax Loss Matters

Every foot of coax introduces some signal loss between your radio and antenna. The higher the operating frequency, the greater the loss.

This becomes especially important for:

• VHF/UHF installations
• Satellite operations
• Long feed line runs
• Low-power (QRP) stations

Keeping feed lines as short as practical helps maximize station performance.

Typical Recommendations

Application	Recommended Cable
HF (<30 MHz)	RG-8X, RG-213
2 Meters	RG-213, LMR-400 equivalent
70 cm	Low-loss coax strongly recommended
Portable Operations	RG-8X
Long Runs	RG-213 or better

Example Losses per 100 Feet

Frequency	RG-58	RG-8X	RG-213	RG-6
50 MHz	3.3 dB	2.5 dB	1.6 dB	1.4 dB
146 MHz	~6 dB	~4.5 dB	~2.8 dB	~2.5 dB
440 MHz	11.2 dB	7.9 dB	4.8 dB	4.3 dB
1 GHz	21.5 dB	13.5 dB	8.3 dB	6.1 dB

Values above are approximate and based upon 100-foot cable lengths. Actual performance may vary depending on manufacturer and installation.  

Important Notes

• Coax loss is approximately proportional to length.
• A 200-foot run will have roughly twice the loss shown.
• A 50-foot run will have roughly half the loss shown.
• Higher frequencies suffer significantly greater attenuation.