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I just downloaded NanoVNA-App and it is a great program.? No crashes and very configurable.Thanks for the tip.
Bob, KN4HH

On Fri, Mar 24, 2023 at 08:56 AM, Bob Watson wrote:

I have learned so much from this group.

So have I!
'GROUPS' are great.
--
Doug, K8RFT

On 25/03/2023 00:10, Peter E wrote:

Peter - VK2AN

Suggest you read the TinySA group for firmware updates and much more.

/g/tinysa/

Have you seen:



Cheers,
David GM8ARV
--
SatSignal Software - Quality software for you
Web:
Email: david-taylor@...
Twitter: @gm8arv

On Sat, Mar 25, 2023 at 07:15 AM, Peter E wrote:

I shall only wax lyrical about how marvelous and reliable these cheap VNA's
and SA's are.

No, but if you blame it you should name it - show a picture of your worse little SA!

Maybe the one for $140 is better, but I suspect not.

And about which device do you talk actually, how much was it?

Very confusing...

OK Jim, from now on I shall only wax lyrical about how marvelous and reliable these cheap VNA's and SA's are. I also won't mention that my H4 failed after less than a year (it definitely is a NanoVNA).
I'm sure that will be much more useful to everyone. :)

Cheers,
Peter - VK2AN

For not having any issues you sure listed a lot of complaints. :)

In re-reading what you wrote I will note that the TinySA/TinySA Ultra do not have a "Standby button". They have an old fashioned power on/off switch. Other comments are not valid for the TSA either. You do not have a TinySA.

73

-Jim
NU0C

On Fri, 24 Mar 2023 21:41:08 -0700
"Peter E" <elekessy@...> wrote:

Hi Jim,

I don't have any "issues". I was just replying to the original thread so others could make a more informed decision on whether to buy one or not...

Cheers,
Peter

Roger, for my purposes, your jig is fantastic. Thamkyou.

73
Mike N7ATC

Hi Jim,

I don't have any "issues". I was just replying to the original thread so others could make a more informed decision on whether to buy one or not...

Cheers,
Peter

It sounds like you do not have a genuine TinySA or TinySA Ultra. If you buy on eBay or Amazon you stand a good chance of getting junk clones. The TinySA products have overwhelmingly positive user feedback in the support group. The developer is responsive and stands behind his product. I am a happy owner of both Tiny variants.

Everything you need to know is here:

/g/tinysa

/g/tinysa/wiki

If you do have a TinySA please take your issues up with the TinySA group.

73

-Jim
NU0C


On Fri, 24 Mar 2023 17:17:36 -0700
"Peter E" <elekessy@...> wrote:

I have just bought one of the 6Ghz ones I needed something to test the YIG in my faulty 6Ghz VNA, It was around AUD$300. They can be bought on Amazon and Ebay.
Initial impressions -

Cons-

1. I nearly sent the unit back as I couldn't get it to turn on, eventually figured out by trial and error that you must hold the "standby" button down for several seconds before it turns on. Absolutely nothing in the pathetic little pamphlet that comes with it about this.

2. Seems to be NO documentation on the unit whatsoever on the web that I could find after a half hour of searching - maybe someone knows of some info somewhere? No evidence of later firmware's etc.

3. No settings at all for sweep speed, Res bandwidth, calibration etc - all automatic.

4. Unit failed after a few days. Finally figured out the on-off switch was intermittent. A dab of WD40 and its going again!

5. If you do a full sweep up to 6Ghz there are MANY spurs all across the spectrum including a giant one at about 3.5Ghz. Unless you zoom in, its quite hard to separate real signals from fake ones.

6. Calibration is no better than about +-5dB on signal levels and seems to vary when changing the Ref. level.

Pros's

1. Actually works OK when you zoom in but Res bandwidth pretty wide

2. Sig Generator also works well and was very handy for testing another spec analyser I have here.

3. Frequency seems fairly accurate.

Summary:

The unit does have its uses, but I'm not sure I would buy another one. Maybe when some updated firmware's come out it will improve. Maybe the one for $140 is better, but I suspect not. At least there may be some more firmware's available.

Just my 2 cents worth.

Cheers,
Peter - VK2AN

I have had problems with different versions of 5. Version 5 was done by a different developer and he has made quite a few changes to the code. There have been several reports of of 5 being "flakey"

Try running the version produced before all the code refactoring. If that works keep moving to later versions until it fails to run for you.



BTW - I have moved on from Saver to NanoVNA app. Much nicer graphs and scaling options. Multiple traces and you can import and compare up to 4 additional s1p/s2p files. Even has built in firmware updating tool for the -H and -H4.
Owen Duffy just released a new version


Roger

Yup. I have the same issue.
I open VNA View program, connect with that, then close that and VNA Saver
will now load, connect and stay alive.
Another guy said to pause scans on the nanoVNA before trying to connect
with saver. I haven’t tried that.

On Fri, Mar 24, 2023 at 7:38 PM Bob Watson via groups.io <kn4hhptc=
[email protected]> wrote:

I also just downloaded V5.5 64 bit running on windows 10 and get the same
results as previously reported. The Nanovna is discovered, it connects and
a few seconds later shuts down.
Bob W





--

*Ralph*
*WA2PUX*
*YouTube Channel:*
Electronics for the Inquisitive Experimenter

Hi Roger,

I have connected to it and even uploaded the firmware, and all seems to work OK. But when I turn the unit back on, just the normal screen with no sweep happening.

Cheers,
Peter - VK2AN

I also just downloaded V5.5 64 bit running on windows 10 and get the same results as previously reported. The Nanovna is discovered, it connects and a few seconds later shuts down.
Bob W

It sounds like the Si5351 approach may indeed be advantageous over linear sweep via ramping a VCO if it allow interesting nonlinear sweeps to be experimented with (including solutions to range ambiguity issues). Nothing inside a coax cable should be moving at high velocities (unless something is VERY wrong!), so I don't see Doppler ambiguity being an issue here. It would also seem like fairly fast pulse repetitions shouldn't cause many problems for "normal" length cables (up to a few hundred feet or so) since the returns are on the order of picoseconds.

If it's straightforward to just take the transform of S11 and yield a FDR plot, then why bother going the extra step to TDR when it arguably doesn't really tell you as much about what's going on in the cable? Maybe it has something to do with peak detection difficulty?

I have just bought one of the 6Ghz ones I needed something to test the YIG in my faulty 6Ghz VNA, It was around AUD$300. They can be bought on Amazon and Ebay.
Initial impressions -

Cons-

1. I nearly sent the unit back as I couldn't get it to turn on, eventually figured out by trial and error that you must hold the "standby" button down for several seconds before it turns on. Absolutely nothing in the pathetic little pamphlet that comes with it about this.

2. Seems to be NO documentation on the unit whatsoever on the web that I could find after a half hour of searching - maybe someone knows of some info somewhere? No evidence of later firmware's etc.

3. No settings at all for sweep speed, Res bandwidth, calibration etc - all automatic.

4. Unit failed after a few days. Finally figured out the on-off switch was intermittent. A dab of WD40 and its going again!

5. If you do a full sweep up to 6Ghz there are MANY spurs all across the spectrum including a giant one at about 3.5Ghz. Unless you zoom in, its quite hard to separate real signals from fake ones.

6. Calibration is no better than about +-5dB on signal levels and seems to vary when changing the Ref. level.

Pros's

1. Actually works OK when you zoom in but Res bandwidth pretty wide

2. Sig Generator also works well and was very handy for testing another spec analyser I have here.

3. Frequency seems fairly accurate.

Summary:

The unit does have its uses, but I'm not sure I would buy another one. Maybe when some updated firmware's come out it will improve. Maybe the one for $140 is better, but I suspect not. At least there may be some more firmware's available.

Just my 2 cents worth.

Cheers,
Peter - VK2AN

There is a nice review/write up and suggestions for future development
of the low cost vna. This paper appears in the IEEE Microwave Magazine
for this month of April, 2023.

An excerpt here attached. As the paper is copyright, perhaps permission
might be asked by a group leader so all might read.

Regards, Alan

Try plugging it into a PC and see if it works with any of the Nano programs.

Roger

Well guys, it appears that my Nano VNA H4 has permanently died. There is a screen display but no evidence of any signal or sweep happening. It did this once before a few weeks ago, and I fixed it by reseating the ribon cable connectors, but now it seems to be dead, and no amount of wiggling, re-seating etc makes any difference. I suspect the re-seating only moved something else on the board with a bad connection.

If anyone has seen this before please let me know.

Even thought these units seem to be very useful, I am rather loathe to buy another one if its only going to last less than a year.

Cheers,
Peter - VK2AN

On 3/24/23 8:09 AM, Will Phillips via groups.io wrote:

Gotcha, I think I understand the difference in the two approaches better now. Did you mean the magnitude and phase data over the sweep is inverse FFT'd? And is there a "format" in the menu that plots this S11 data directly? (I love the nanoVNA's feature set and performance, but the UI is ... not the best I've ever used).

Actually, not the magnitude and phase, but the real and imaginary parts of the S11. You can display Re and Im.

What is the purpose of the small, constant offset between the stimulus and the detection oscillators?

It creates an audio tone at 5kHz, which can then be sampled by audio ADCs, and you do some simple dsp to get I/Q.

Converting to baseband means you have to worry about things like 1/f noise, DC bias, etc. With 5 kHz, there's easy AC coupling and so forth.

If I were interested in using the nanoVNA as a sort of FMCW homodyne radar, could a firmware tweak set it to track the stimulus oscillator?

You don't need to do anything - just measure S11, transform it, and you've got a classic FMCW radar. People do this all the time in the lab with a VNA. The trick is making sure that you understand the ambiguity distances and phase wraps. A reflection at multiple distances will give exactly the same phase.


What the radar altimeter does is work at long ranges, with simple equipment. Long before you could generate stepped frequencies and measure phases, you could do a linear sweep (driving a VCO with a ramp), and get an audio tone that was proportional to the time delay - a useful thing if landing an airplane, or deciding if you need to apply the brakes on a truck or bus.

Chirped pulses with pulse compression are another similar thing - generate a chirp, have a matched dechirp in the receiver, and you can get the equivalent of high peak power, but with low power longer duration.

All these things can be done with DSP - But you can do nice things like do stepped frequency where the step pattern is random or both up and down, and that can help resolve range/Doppler ambiguity. Consider the classic homodyne radar altimeter (also used to do stuff like measure the velocity of artillery shells on a test range). The output of the mixer is a frequency proportional to range *if* the target is stationary. If the target is moving, then the frequency is the range combined with the Doppler. If you sweep both up and down, though, you can resolve this: One will have frequency Doppler + range/sweep rate and the other will have Doppler - range/sweep rate. With a simple low frequency detector scheme you can then get both range and range rate(velocity).

If you want to use a high pulse repetition frequency, then you have a range ambiguity problem - Am I seeing the return from the most recent pulse or the pulse before it (so the range is really c/pri bigger). Sometimes you can resolve this by geometry - you KNOW that there are no targets in the first ambiguity zone: If'm I a radar in low earth orbit at 800 km (round trip time of 48 milliseconds) and my PRI is 15 milliseconds, then I know I'm looking at 4 pulses ago.







I am starting to think that maybe the device I am looking for is actually a spectrum analyzer with a tracking generator, which is the one feature the tinySA doesn't seem to have - I may hop over to their groups.io to ask for clarification.

The existence of the tinyPFA firmware, which turns the nanoVNA into an entirely different instrument with no hardware changes, and derivatives of the nanoVNA such as the tinySA have me wondering what might be possible with just the out-of-box hardware and an alternative firmware - in theory, the STM32 could even run onboard neural networks or something. Range resolution of the FMCW would be less than spectacular until something like a few GHz is reached, but the level of firmware compatibility with faster and newer versions of the nanoVNA might enable solving that problem with relatively little difficulty.
Thank you for all your help!

Be careful about buying one via eBay. There have not been any reports of the Ultra being cloned yet but it is inevitable and the clones are inferior. You can find a list of authorized sellers here:



73

-Jim
NU0C

On Fri, 24 Mar 2023 08:37:08 -0700
"WB4LVA" <ernie50Johnston@...> wrote:

TY. I did not know. Should have checked.