Cable Attenuation Calculator

Calculated Results

Results appear here after submission and stay above the form.

Total Attenuation

0 dB

Received Power

0 dBm

Power Delivered

0 %

Link Margin

0 dB

Estimated Max Length

0 m

Status

Ready

Cable Attenuation Inputs

Preset values are convenient engineering estimates. Edit any field when you need a datasheet-matched custom model.

Cable Preset

Select a preset or enter your own attenuation model.

Attenuation at Reference Frequency

dB / 100 m

Reference Frequency

MHz

Operating Frequency

Frequency Unit

Frequency Exponent (k)

Cable Length

Length Unit

Input Power

Input Power Unit

Number of Connectors

Loss per Connector

dB

Number of Splices

Loss per Splice

dB

Extra Fixed Loss

dB

Allowable Loss Budget

dB

Receiver Sensitivity

dBm

Example Data Table

These rows are illustrative examples for planning and comparison.

Cable	Length	Frequency	Connectors	Splices	Total Attenuation	Received Power
LMR-400	30 m	900 MHz	2	0	4.06 dB	25.94 dBm
RG-58 Coax	20 m	450 MHz	2	1	7.50 dB	12.50 dBm
CAT6 UTP	80 m	100 MHz	2	0	18.00 dB	-8.00 dBm

Formula Used

1) Frequency-adjusted attenuation per 100 m
α_f = α_ref × (f / f_ref)^k

2) Cable-only attenuation
Cable Loss = α_f × (Length in meters / 100)

3) Discrete component losses
Discrete Loss = (Connectors × Loss per Connector) + (Splices × Loss per Splice) + Extra Fixed Loss

4) Total attenuation
Total Loss = Cable Loss + Discrete Loss

5) Received power
P_received,dBm = P_input,dBm − Total Loss

6) Power delivery percentage
Power Delivered (%) = 100 × 10^{(−Total Loss / 10)}

7) Voltage ratio
V_out / V_in = 10^{(−Total Loss / 20)}

8) Estimated maximum cable length
Max Length = ((Loss Budget − Discrete Loss) / α_f) × 100

How to Use This Calculator

Select a preset cable or enter a custom attenuation model.
Enter the operating frequency and choose the correct unit.
Enter cable length, connectors, splices, and any extra fixed loss.
Add input power, allowable loss budget, and receiver sensitivity.
Press Calculate Attenuation to view total loss, received power, link margin, and the frequency-response graph.
Use the CSV or PDF buttons to export the current result summary.

Frequently Asked Questions

1) What is cable attenuation?

Cable attenuation is the signal power lost while energy travels through a cable. It is usually expressed in decibels and rises with distance and frequency.

2) Why does attenuation usually increase with frequency?

Higher frequencies generally experience greater conductor and dielectric losses. That is why long RF and data runs often need better cable or shorter routes.

3) Are the preset cable values exact?

No. They are planning estimates. Real attenuation depends on manufacturer data, temperature, installation quality, bend radius, shielding, and test conditions.

4) What does link margin mean?

Link margin is the difference between received power and receiver sensitivity. A positive margin usually indicates usable headroom for stable operation.

5) Why include connector and splice losses?

Short runs can still fail a budget when connectors, adapters, and splices add noticeable loss. These small items often matter in tight system designs.

6) Can this calculator be used for data cable planning?

Yes, for rough insertion-loss planning. However, certified network designs should still follow the exact cable category standards and vendor test limits.

7) What is the estimated maximum length output?

It is the cable length that stays within the entered loss budget after subtracting connector, splice, and extra fixed losses from the total allowance.

8) Does temperature affect attenuation?

Yes. Temperature can change conductor resistance and dielectric behavior. Hotter conditions may increase loss, so critical systems should include environmental margin.