Loss is a length multiplier, so a 200 ft length would have twice the loss shown above and a 50 ft length would have half the loss. This multiplier factor is why you should keep cable installation lengths between radios and antennas as short as practical!

Here are typical signal attenuation figures (loss) for common coaxial cables at around 1.42 GHz (1420 MHz) — expressed as dB per unit length, for comparison losses at different frequencies. Coax loss increases with frequency, so, for example, you’ll see higher losses at UHF compared with VHF, and even higher losses at microwave frequencies (or 1420 MHz).

Cheaper cables, such as RG-6, can be used as long as there is filtering and amplification at the masthead (just behind the waveguide) using a low power amplifier and filter such as the Nooelec SAWBird H1+ LNA.

LNAs should always be positioned close to the waveguide and not at the other end of the coaxial cable near the software defined radio (SDR), due to attenuation, regardless of which type of cable you use.

📡 Approximate Attenuation at ~1.4 GHz (1420 MHz) of key coaxial cable choices for amateurs

📊 Practical Summary for comparison of RG-58, RG-6, LMR-240, and LMR-400 coaxial cables

• RG-58: Poor choice for ~1.42 GHz unless cable run is very short — loss is very high.
• RG-6: Good choice, cheap price point and impedance mismatch for 50 Ω systems.
• LMR-240: Mid-range performance—moderate loss for medium-length runs.
• LMR-400: Best of the listed options for low loss at ~1.4 GHz, suitable for long runs if you need low attenuation.

📡📊 Extending the analysis to wider range of coaxial cables

Here’s a comparative table of typical attenuation (loss) around ~1.42 GHz (1420 MHz) for a wider set of common coaxial cables — mostly expressed as dB loss per 100 m (you can easily convert to dB/100 ft by dividing roughly by 3.3). These figures are drawn from published attenuation charts and manufacturer data. Actual loss varies with exact make/model, temperature, and installation, but this gives a practical engineering reference.

📊 Attenuation (dB per 100 feet) from https://www.w4rp.com/ref/coax.html

Other options:

Aircell 7 (Low Loss Coax) (7mm) – excellent modern cable choice:

Aircell 7 (7.3mm OD) is an ultra-flexible, small bending radius, low-loss coaxial cable for frequencies of up to 6 GHz. Impedance: 50ohms, Outer Diameter: 7.3mm, Bend Radius min. 25mm, Weight (100m: 7.20kg

Typ. attenuation (dB/100 m @ 20°C) : 5 MHz – 1.6, 10 MHz – 2.2, 50 MHz – 4.52, 100 MHz – 6.28, 144 MHz – 7.6, 200 MHz – 9.04, 300 MHz – 11,2, 432 MHz – 13.6, 500 MHz – 14.72, 800 MHz – 19.0, 1000 MHz – 21.52, 1500 MHz – 27.08, 2000 MHz – 31.88, 3000 MHz – 40.88, 4000 MHz – 49.12, 6000 MHz – 64.9.

📌 Quick Practical Notes

• Small jumper coax (e.g., RG-58, RG-8X) – more flexible on cable choice.
• Mid-size low-loss cables like LMR-240 / LMR-400 / 9913 are popular for UHF use and balance performance and flexibility.
• Larger “Heliax” type coax (½″ and up) offers much lower attenuation per length and is ideal for long runs, but is heavier and more expensive, and not applicable when cable needs to be flexible. It is also problematic for small dishes due to its excessive weight.
• LMR-600 sits between flexible coax and large Heliax, giving low attenuation with reasonable flexibility.