You need to specify the frequency. Typically, coax loss is speced at 200MHz but this may differ according to the manufacturer. Very roughly the attenuation at a different frequency can be estimated by multiplying by the square root of the ration of the two frequencies. i.e a cable with 10db loss / 100m at 200MHz will have abpout 14dB/100MHz loss at 400MHz. However, construction of the cable can change this. Most of the loss is resistive, caused by the decrease in skin depth with increasing frequency (hence the square root law) but diaelectric losses can also come into effect (these are roughly proportional to frequency) as can losses due to a drop in screen effectiveness (i.e. radiation losses). Copper clad steel conductors (eg RG62) type construction can be a real headache! Measurement is usually made using a signal generator and RF power meter or millivoltmeter. Tou may be able to get some sort of estimate using ameteur VHF equipment & scaling the result. Of coarse, to measure propery the cable must be matched properly also. To measure the length of the run you could use an ohmmeter as you suggest, just by shorting the far end and measuring the loop resistance, Commercially, the length of a coax cable is estimated by either measuring the capacitance or using a TDR. (The DC resistance is less well defined than the capactance or (normally) the velocity factor). Richard P Hello all, I'm looking for a method to measure signal loss (db) on RG6 and RG11 coax cable. I think I can do this with just an ohm meter, but I'm not sure how to cap the opposite end. What I'm trying to accomplish is to (1) calculate the actual loss on a coax run, and (2) calculate the length of the run by comparing signal loss to the specs from the manufacturer. Most coax manufactures (I believe) specify signal loss per foot. Any help greatly appreciated, Chris -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics