When deploying coaxial cables in RF communication, CCTV systems, or broadband networks, power loss—also called attenuation—is one of the most important factors to consider. But how much signal are you actually losing per meter? And does it matter if you use RG58, RG6, or LMR-400?
In this article, we’ll break down everything engineers, integrators, and technical buyers need to know about coaxial cable attenuation per unit length, with clear tables, examples, and real-world guidance.
What Is Power Loss in Coaxial Cables?
Power loss in coaxial cables refers to the reduction in signal strength as it travels along the cable. It is typically expressed in decibels per meter (dB/m) or dB per 100 feet, depending on the standard.
Key Contributors to Power Loss:
- Conductor resistance (I²R losses)
- Dielectric material loss
- Radiation and leakage
- Skin effect at high frequencies
Formula:
Loss (dB) = Cable Length × Attenuation per unit length
The longer the run—and the higher the frequency—the more loss you’ll incur.
Coaxial Cable Loss by Frequency – Comparison Table
Here’s a comparison of typical attenuation values for common coaxial cables:
| Cable Type | @100 MHz | @500 MHz | @1 GHz | @2.4 GHz |
|---|---|---|---|---|
| RG58 | 0.5 dB/m | 1.2 dB/m | 1.8 dB/m | 2.9 dB/m |
| RG6 | 0.3 dB/m | 0.7 dB/m | 1.1 dB/m | 2.1 dB/m |
| RG213 | 0.2 dB/m | 0.5 dB/m | 0.8 dB/m | 1.5 dB/m |
| LMR-400 | 0.1 dB/m | 0.3 dB/m | 0.5 dB/m | 0.9 dB/m |
Note: Loss increases with frequency. If you’re transmitting 2.4 GHz WiFi or higher, low-loss cables become essential.
What Affects Power Loss in Coax Cables?
1. Frequency
Higher frequencies experience more attenuation. Doubling the frequency nearly doubles the loss.
2. Cable Structure
Thicker cables (e.g., RG213) have lower resistance and thus lower loss. Shielding also affects leakage.
3. Material Quality
Solid copper is better than copper-clad steel. PTFE dielectric has lower loss than PE.
4. Environment
Temperature and moisture increase loss. UV and physical damage can also degrade performance.
How to Calculate Power Loss in Your Setup
Let’s say you’re installing 30 meters of RG58 for a 900 MHz signal:
- From the table: RG58 @900MHz ≈ 1.6 dB/m
- Total Loss = 1.6 × 30 = 48 dB
That’s significant! You’ll lose most of your signal unless you:
- Reduce cable length
- Use a lower-loss cable (e.g., LMR-400 @0.6 dB/m → 18 dB total)
- Add a line amplifier or active antenna
Use Times Microwave Calculator for custom cable loss estimates.
Recommended Bafitop Low-Loss Coax Cables
| Model | Frequency Range | Attenuation @1GHz | Application |
|---|---|---|---|
| RG6 Pro | 5–1000 MHz | 1.1 dB/m | TV, DTV, broadband |
| RG213 Elite | up to 3 GHz | 0.8 dB/m | Base stations, VHF/UHF |
| LMR-400 EQ | up to 6 GHz | 0.5 dB/m | Long-run WiFi, telemetry |
All our cables are RoHS compliant and available with SMA, N-type, F, or BNC connectors.
Need help choosing? Email us at sales@bafitop.com or call +86-15817341810.
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Engineer’s Judgement: When to Switch to Low-Loss Coax?
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If your run length exceeds 20 meters above 1 GHz
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If your frequency is >2.4 GHz (e.g., WiFi, microwave)
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If you’re powering active antennas (PoC)
Ask yourself:
“Can I tolerate 10+ dB of signal loss on this cable run?”
If not, you need to upgrade.
FAQs
Q: What’s an acceptable power loss per meter?
Depends on system sensitivity, but <1 dB/m is ideal for high-frequency runs.
Q: Can I use RG6 for 2.4GHz WiFi antennas?
Only for very short runs (<5 meters). Otherwise, use LMR-400 or similar.
Q: Is coax loss linear with length?
Yes. Double the length = double the loss, assuming same frequency.
Q: Does cable bending increase loss?
Tightly bent cables may cause micro-fractures or impedance mismatch → slight increase in loss.
Ready to Optimize Your Signal Path?
Don’t let attenuation ruin your RF performance. Choose the right cable based on frequency, run length, and application.
📧 Email: sales@bafitop.com
📞 Phone: +86-15817341810
Get a quote, request datasheets, or sample a low-loss coax today.
