# Simple question regarding coaxial cable

I have a coaxial cable whose length is $$L=10m$$, working at $$f=1GHz$$ frequency and i need to determine it's attenuation coefficient (if that is correct term), however i cannot find any relationship between these three values anywhere on the internet so i would appreciate if someone could help me! Thanks in advance!

• You have to ask the manufacturer. It depends very much on the specific materials used. Feb 2, 2019 at 21:28
• @DaveTweed well, i measured attenuation in dBm for some frequencies, for example, at 900MHz i got 5.8dBm, can i use this somehow to calculate attenuation coefficient? Feb 2, 2019 at 21:35
• I bet something like that could be used to extrapolate although I personally don't know how. You should click edit and add that neatly to your question though, and if you have tested sample values at more than just 900MHz, you should provide them, without going overboard.
– K H
Feb 2, 2019 at 21:51
• Nothing attenuates by 5.8dBm. A dBm is a measure of power (dB above or below 1mW). A cable may attenuate by 5.8dB, though. If it does attenuate by 5.8dB at 900MHz, then it probably attenuates more at 1GHz, and that's about as much as you can say without consulting the manufacturer's data sheets. Feb 2, 2019 at 22:14
• If it has a type number (e.g. RG58) then its maximum attenuation characteristics are part of the number, which you can look up on the web. Feb 2, 2019 at 22:15

the data sheet of your table should provide constants for it, the formula I see often is

$$att_{db}=(K_1\sqrt{freq})K_2freq$$

whoever makes your cable sometimes provides their constants in the documentation so you can get an estimate. If there are none, find a similar cable an estimate with a maker that provides them. Usually they end up giving you a value per unit of length.

I really do not know how to write equations properly on here.