Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would
be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate
that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views.
It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if
you would like to post something on RF Cafe's
page, please do.
Below are all of the forum threads, including all
the responses to the original posts.
Post subject: Regarding Cable Loss
Unread postPosted: Thu Jun 16, 2005 11:38 pm
I had a question regarding measuring cable loss, How to connect the equipments to calculate the cable
loss from one end of the cable to another if you have a Signal Generator, Spectrum Analyser and Power meter. How
should I connect the cable to and what are the parameters Should I change to know the cable loss.
Post subject: Cable Loss Measurement
postPosted: Fri Jun 17, 2005 1:26 pm
Assuming you've got cable and equipment with the same impedances
(usually 50 Ohms):
1. Measure output of signal generator with power meter
2. Insert significant length
of cable between signal generator and power meter.
3. Measure output from cable
4. a. Cable loss (dB) = dBm(gen)
- dBm(cable output)
b. Cable loss (fraction) = Pout(cable)/Pout(gen) powers in W, mw, etc.
some power meters require external termination - you will, of course, have to provide that.
point is that the terminating impedance must be equal to the characteristic impedance of the line for this simple
method to work.
Remember that cable loss is a function of frequency, so measure at the frequency or
frequencies that you're interested in.
Regarding Cable Loss
Unread postPosted: Fri Jun 17, 2005 1:45 pm
Thank you very much,
impedances are at 50 ohms also you have told to measure signal generator with power meter, so mean just input some
power from gen into meter and check the reading on the power meter? for that frequency.