"Jimmie D" wrote in message
...
I need to measure the loss of aproximately 200ft of coax @ a freq of 1Ghz.
The normal procedure for doing this is to inject a signal at one end and
measure the power out at the other. Using available test eqipment this is a
real pain to do. I propose to disconnect the cable at the top of the tower
terminating it in either a short or open and measure the return loss at the
source end. I have done this and measured 6.75 db and I am assuming that
1/2 of this would be the actual loss of the cable. These numbers do fall
within the established norms for this cable. Can you think of a reason
thiis method would not be valid?


Jimmie

Hi Jimmie

I consider "return loss" to be a ratio related to the mismatch of the load
to the line. A short on the end of a low loss line will have high Return
Loss. You probably did some math that isnt apparent in the statement "I am
assuming that 1/2 (of 6.75 dB) is the actual loss". .

How difficult would it be to take a length of some decent RG-6 up the
tower to send the signal down to the *lower end*?

Jerry