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This is my first post.
I am Old.? Licensed for 65 years so my "New Skill" learnin' ain't what it used to be.
I have a FA-VA5.
I want to use it to do TDR.
I need a 1,2,3,4 Cookbook to set it up if that is possible.
Can someone help me with this.? I have VNWA and can put the FA-VA5 on USB, calibrate it and get the screen readout going but that is about all I have accomplished.
I have produced what I "Believe" to be a TDR of my K9AY receive antenna feedline coax.
I do not see a linear measurement at the base of the screen like other programs I have see show, it is in nanoseconds which can be transformed to Length.
My Length conversions on the hlittle carat markers are in Meters....can I change to Feet?

I probably went about the wrong way to setup this reading on the chart/scree,
can someone please give me a simple Cookbook tutorial and walk me through the setup to get the TDR screen on and accurrate?

I don't even know what S21, S11, Memories, and the like mean in setup? S1.p etc....IZI included.? but I am trying......But I have somehow maneuvered to a screen in VNWA that shows what I believe to be a TDR but unsure of settings/ohms/meters vs time/feet, etc...
HELP!!!

Val
N4RJ (Old and obviously not prepared to use this nice device properly)

Am I too far gone for Help?
Or, is anyone using this thread?

Still lost in the Ozone down here.

Thanks

Val

N4RJ

Val, this group is alive, but not really active. Your request for a how-to cookbook for TDR measurements is a pretty large request. Like you, many of us have lots of time, but not so much energy. I for one will try to find the info you need. Will take some time tho.
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VY 73,

Wes AE6ZM

As a start, since it seems the trouble you are having is with the VNWA software you might take a look over at the VNWA group on Groups.io.
--
VY 73,

Wes AE6ZM

Hello Val
thanks for your message. So far, I have found out that it is indeed possible to make TDR measurements in conjunction with the DG8SAQ VNWA software.
The best way to get you going is perhaps by using a piece of coax cable with known electrical length. You should observe near total reflection from the end of the cable. (propagation time would be related to twice the cable length - forward and back).
I have not used the TDR option myself yet and won't be able to try for a while but perhaps other group members would like to jump in and describe the process or post pointers to web-articles on the subject.

I did find this article which might be of some interest:



73
Dieter, VK3FFB

generally applicable video:??

if you permanently attach a 50 ohm load to the nanoVNA's second port (CH1, S21), then what you have is roughly equivalent to the FA-VA5.

Thanks for the informations, I will dig into it.
Val

N4RJ

Hi Val!

I don't know if you're making it work yet, I tested a bit now that it's holiday time and made it work. I was well helped by this attached description. It is important to "double-click" on time4 (if you have set Trace4 to RE dB, and make setting picture 12. If it still doesn't work, get back in touch and I'll see if I can make a "run schedule" to find the right settings.

It starts on page 11.

Regards Roger
73 de SM0LTV