Method finds faults in coaxial cables. This article describes how to use a spectrum analyzer instead of a time-domain reflectometer (TDR) to find opens or shorts in a coaxial cable. Basically, using this method, you’re measuring the frequency response of the stub created when a fault occurs. It occurs to me that you could possibly also use an antenna analyzer to make this measurement, depending on where the fault is and the frequency range of the analyzer.
10 scopes for under $1500. The scopes discussed in this article range in price from $318 (Siglent SDS1072CML) to $1311 (Keysight DSOX2002A) and bandwidth from 40 MHz to 100 MHz. If you’re thinking about buying a scope for your shack, this article might be a good start. It’s just a start, though. I think it’s missing other good choices, such as the Siglent SDS1152CML that I have. the SDS1152CML has a 150 MHz bandwidth and costs about $450.
Getting started with antenna measurements. In amateur radio, we talk a lot about antenna performance, but really have very little in the way of data to back up our discussions. The reason for this is that making antenna measurements isn’t easy. This short blog post gives a little insight into this complex topic.
Dave New, N8SBE says
I used the setup shown to trim my 1/4 wave length matching sections for my quad antenna, using my MFJ antenna analyzer. By inserting the 50 ohm load in series with the coax, I could trim the far end until the analyzer showed a 1:1 match at 50 ohms. This uses the concept that if the far end of a 1/4 wave length of coax is open, the end attached to the 50 ohm load is shorted (at the frequency of interest), thus making a circuit with the 50 ohm load connected across the analyzer to ground.
Works like a charm.