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Does the nanoVNA have a TDR function? For some reason I thought it did, but
I can't find it in the menu.

Zack W9SZ

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Yes, it is not labeled 'TDR' in the menus. Instead it is appropriately labeled 'Transform', since it is not a true TDR, but simulation of a TDR via Fourier Transform. On the menus: Display -> Transform. Usually the "Low Pass Impulse" is an appropriate selection. There are some videos you can find online that describe its use. Also messages in this group from a long time ago. It requires setting up the frequency scan range appropriately for the corresponding time-length you require, which can be a bit counter-intuitive, and you need to take care to set it appropriately to avoid aliasing, which would give a false answer. But it works very well once you know how to set it up.
Stan KC7XE

About differences TDR and VNA TDR



Also about VNA TDR options

Great references, thanks!

W2AEW has a very helpful video on this subject, as well as many very help
videos regarding the nanoVNA & ham radio in general:



Thanks,
Robin Midgett K4IDC


On Mon, Dec 30, 2024 at 5:58?PM Matthew Rapaport via groups.io <quineatal=
gmail.com@groups.io> wrote:

Great references, thanks!

Thanks! As it turned out, I have a RigExpert AA-600, and it was very easy
to use as a TDR. Much easier than the NanoVNA.

Somewhere I have a real TDR, a TEK 1502. But it's in storage and is so
buried I couldn't find it.

My concern about the site was that the cable and antenna (for an FM radio
station) that I needed to measure is on a tower with many other antennas on
it. Instructions for the AA-600 note that transmitted signals from nearby
antennas could affect the TDR measurements and even possibly damage the
instrument. I suppose this could hold true for the NanoVNA, too. There did
not appear to be any effects of other signals on the TDR measurement when I
made it.

Zack W9SZ

On Tue, Jan 7, 2025 at 8:48?AM Robin Midgett via groups.io <RobinK4IDC=
gmail.com@groups.io> wrote:

W2AEW has a very helpful video on this subject, as well as many very help
videos regarding the nanoVNA & ham radio in general:



Thanks,
Robin Midgett K4IDC


On Mon, Dec 30, 2024 at 5:58?PM Matthew Rapaport via groups.io <quineatal=
gmail.com@groups.io> wrote:

Great references, thanks!