I have been reading about various methods to perform a Cable Path Loss for RF Testing but not being a core RF person, I needed some insights on how it is done in Field or Lab. Here is my understanding so far:

Method1: Signal Generator + Power Meter Generate about 0 dBm of power from the Signal Generator and measure the same on the Power Meter e.g. assuming 10 dB pads + cable loss 5 dB = -15 dBm (this the total cable path loss).

Method2: Network Analyzer Connect the 2 ends of the paths to Port 1 & Port 2 of the Network Analyzer and measure the S21 parameter.

I kind of get the idea of Method 1 but do not understand the Method 2 much.


1 Answer 1


When you're using a network analyser to measure S21, it generates a signal on port 1, and receives a signal on port 2. S21 is a measurement of the ratio of those signals.

While a network analyser does much more than a signal source and power meter can (S21 is the complex ratio), for this cable loss application, if you display simply the magnitude of S21, you can regard it as a signal source and power meter in a single box.

  • \$\begingroup\$ So it would mean, I can configure my Network Analyzer to a particular Frequency & Power level, which would be incident on the Port 2. And the Network Analyzer should provide an S21 measurement which is loss for that Cable Setup connected between Port 1 & 2. And this can simply be repeated for multiple frequencies. \$\endgroup\$
    – eecs
    Mar 9, 2017 at 7:18
  • 1
    \$\begingroup\$ Chaee, one of the jobs of a network analyzer is to do thing for many frequencies in succession. You might really want to read an intro to network analyzers. \$\endgroup\$ Mar 9, 2017 at 14:34

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.