Try to find/borrow a older Tek 1502 TDR, they are inexpensive on ebay (~$100) and show way more detail than any of the analyzers I've tried.
73 Don VE6JY On Fri, Oct 16, 2020 at 5:50 PM Michael Walker <[email protected]> wrote: > RigExpert has a variety of Antenna Analyzers that have a built in TDRs. > > I highly recommend them. > > Mike va3mw > > On Fri, Oct 16, 2020 at 5:15 PM Jim Brown <[email protected]> > wrote: > > > On 10/16/2020 1:26 PM, Gary Smith wrote: > > > What would be an easy way to tell if these > > > coax have been damaged in some way? > > > > > > I do have an old MFJ-259B > > > > That might give you a clue if the cable is open or shorted, but it's > > unlikely to show chewing that doesn't cause an open or short, but allows > > water intrusion, etc. > > > > The best tool is a vector analyzer that includes software/firmware with > > a very good TDR function. I use the VNWA3EC, built by hams in the UK > > from a design by DG8SAQ, who also does both firmware and software. > > > > https://www.sdr-kits.net/DG8SAQ-VNWA-models > > > > The TDR function in this unit is really excellent, and can be used with > > the antenna connected. The procedure is to do a very wide sweep (I > > usually sweep 50 - 500 MHz) so that fine detail shows up clearly. > > Software then does an inverse FFT on the sweep to get the TDR, and > > allows the user to choose which of five different windowing functions > > provide the clearest view of the measurement. > > > > There are ultra-cheap VNAs around, but I don't know the capabilities of > > their operating software. > > > > One way I test my RX antennas is to use them to listen on the AM BC band > > while I switch directions, using this FCC website to tell me who is > > where on each frequency. > > https://www.fcc.gov/media/radio/am-query > > > > 73, Jim K9YC > > _________________ > > Searchable Archives: http://www.contesting.com/_topband - Topband > > Reflector > > > _________________ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
