I've purchased some well made cables with SMA males on each end from Amazon to replace the jumper cables that come with a typical basic NanoVNA - as others have mentioned on here, the quality control varies with the cables included with the basic NanoVNA kit - I own three (basic "H" version) NanoVNA's, and over time, two of the cables have become intermittent. I have also shopped around trying different vendors that make the double-female SMA connector (the "Thru" connector) as I found a few that get intermittent with use - you'll know something is not right after you complete a calibration session and discovered what looks like a 3 year old had scribbled on the smith chart of the NanoVNA display - that's a warning sign that you have an intermittent cable, connector or thru adapter - you'll then need to isolate which item is intermittent, replace it and then re-do your calibration process.
Brian - KI8KY
