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It's useful to know how to make the TDR work - I've found more than one feedline problem by using TDR - yeah, sometimes if there's combinations of solid, foam, and air dielectric, the distances don't

Is your coax foam or solid dielectric - RG-6 comes in both forms. What does the trace look like? (can you save it and post it?) I'd expect around 41-42 meters if set to VF=1 (or 100%). if it's set

If it is indeed a USB communication error as others have suggested, have you tried using a different USB cable between the NanoVNA and PC? Maybe even try a different USB port on the PC. Are you

Why are you using TDR to do this task? Just sweep from 50 kHz to 20 MHz and set yellow trace to s11 Phase and Green to Smith chart. Then just spin the marker and you can see what you want.

To directly answer this, what you need to know is the electrical length of the cable, not the physical length. And nanovna-saver can directly display this without the complication of TDR and VF

Here is a new twist .... I replaced current , unknown type , unmarked type of coax with known, good RG6 length plainly marked in cubits and converted them to meters - approximately 35 meters. Now

I tried a couple of ferrite beads also tried updated software but no luck. I need to get a few more beads to see if that works. Like Stan, I am suspicious that it might be RF. May be a few weeks

Step size (span/number of points) sets the "unambiguous range" - if the steps are too far apart, then the true length might be a multiple of 1/step size longer. So, if you've got, say, 100 ft of coax

OK, the discussion did covered the theory , now is the time to apply it and be practical. . I shall repeat the task is - is the unknown length of cable in multiples of 1/4 wavelength @ 14 MHz

I have a NanoVNA H4 and it's great for measuring antennas from inside the shack, but not quite rugged enough to used outside up a ladder. Also the display is hard to read in the sunshine. For outside

This would be known as "dispersion" and would cause problems with either the pulsed (time domain) or swept frequency (synthetic time domain) approach. A fast pulse (as used in TDR) has all

Coax is, of course, not identical to paired cable, but using a low end of 50 kHz makes me wonder whether the velocity might be lower than the published high frequency value sufficiently to skew the

All of them together. It will show the SWR of the combined elements, it has no way to distinguish one from another. 73, Don N2VGU

I take a known length of the coax of the same physical batch and do a TDR and see what the measurement is and physically measure the sample coax and then can change the velocity factor to equal the

There are many models. The smallest, cheapest is about $60. And any (nanovna) model will also need connector adapters. The models with larger screens than the small 2.8 inch $60 model are easier to

That depends on your "sweep width" setting - the START and STOP frequencies. -- Doug, K8RFT

If you are sweeping across all bands the antenna is designed for as the NanoVNA sweeps across each resonant point it will indicate the SWR for each band. If you had a fan for 40, 20, and 15 meters

my friend....dont listen to what people say when they tell you nano vna isnt as good as a REAL antenna analyzer because that exactly what a nano vna is. only is generally has more features than

All of them together. It is showing the swr of the system of antennas. If one of the elements is for 20M, the swr at 14MHz is primarily affected by the 20M element - but the other nearby elements