NanoVNA Custom Software

[bd139]

Same situation here.

Oh yeah our local 2m net which appeared to switch between growing strawberries, bitching about your wife and being offended that a black person walked past

[joeqsmith]

I'm not a psychologist, but it's almost like they don't want to do anything that could result in failure. They don't want to be seen as not being able to do something or figure it out. So, they just don't do it. They don't like to talk about any sort of technical topic that they don't know already, because then the other person would seem to be smarter than they were (at least on that topic).

Of course politics and religion they talk about, because there is no "failure" involved. It's just opinions on subjective topics. But once the microphone is in their hand, they will let the opinions fly.

Of course they will fail at simply hooking up HAM gear, but they're willing to risk that or they couldn't talk to other people on the radio, but that's as far as it goes.

If they fail plugging things in, it's behind closed doors, not in front of their peers.   

It's too bad OWO censors their groups.io reflector.  I would have liked to have had an open discussion with Tom W8JI, about his thoughts on transient protection.   He certainly had an opinion on the subject but once others started to point out where he was wrong, he went silent.    I suspect much for the reasons you mention.  Or, it's because OWO would pull my posts not allowing a dialog to take place.   

https://nanorfe.com/forum/ESD-safer-circuit.html

[bd139]

Sound like an unhealthy community although I certainly understand the approach.

As for transient protection, isn't it just an SA612 on the front end? Just stick another one in 

[joeqsmith]

The LiteVNA has TVSs on both ports.   Not sure that would save you when you transmit into one of the ports.   Never gets old.

[bd139]

Not sure I can face watching that after watching a YT the video of a smoked front end on a Rigol DSA815TG 

Nice to hear if someone actually giving a crap about robust engineering at least.

[xrunner]

Not sure I can face watching that after watching a YT the video of a smoked front end on a Rigol DSA815TG 

Oh I have one of those, that would make a grown man cry. You know they really should print the Max Power Input right there by the input connector so these things don't happen.

Oh wait - it is there!

MAX +20 dBm

 

[bd139]

Bold of you to assume that someone both read and understood that! 

Through safety squints: “Hey Bob it says 20 something. Must be watts”. CEEEEE CUUEEE CEEEEE CUUEEE. Sniff sniff. Hmm burning.

[joeqsmith]

To be fair, even a 5W CB could have damaged it.... but we know it was a ham! 

[xrunner]

Bold of you to assume that someone both read and understood that! 

Through safety squints: “Hey Bob it says 20 something. Must be watts”. CEEEEE CUUEEE CEEEEE CUUEEE. Sniff sniff. Hmm burning.

HAMs I talk to can't relate to "dBm". Like on the Spec-An +20 dBm is the Max power input - they wouldn't know what that is.

They generally know that a cable loss or attenuation of 3 dB is 1/2 power loss, and 10 dB increase in power is ten times more. But they don't do dBm at all. Haven't a clue.

So I'll say so-and-so's transmitter was supposed to output +50 dBm and I found it was only +47 dBm - they don't understand that. They ask me "why do you say dBm instead of watts? I just say "Because that's how I was taught."

[bd139]

That'll be because dB is a relative logarithmic measurement and they understand neither what logarithmic or relative measurements are! Add the poor understanding of SI prefixes and even the reference point in dBm is unlikely to be understood.

There must be a way of making some easy money out of that though. Perhaps create a knowledge cult of dBm and then sell a conversion device that turns a smaller number into a bigger one somehow

[joeqsmith]

Still, we have the internet and there are several conversion calculators available to the ham....  Oh right as our new friend reminded us, they have trouble navigating the internet.   

Maybe just remember that 20dBm is 100mW which was the amount of power from their childhood walkie talkies.  Have any better ideas on how to remember it,  keeping in mind, they need to remember it longer than what it takes to pass a test?

[bd139]

I'll have you know my childhood walkie talkies could kick out a bit more than that (Midland shit + completely illegal Italian CB widowmaker tube amp) 

But yeah no looky no findy. Monkey expect spoon fed. I'm sounding like grugbrain now https://grugbrain.dev/

[kd7eir]

I'm an extra class ham. I ran into several roadblocks trying to get Solver64 installed and working.

Did I whine and moan? No. I dug, and dug, and dug until I found the information I needed to get the job done. In the end, I not only got Solver64 working on my own, but I gained a lot of valuable knowledge that will serve me going forward.

It's a shame that so many of my fellow hams have no desire to tackle an issue and work it to resolution. Needing help is fine, but you need to do your due diligence before asking for help, and you need to be humble in your requests.

[joeqsmith]

Outside of learning how to install it,  what have you used the software for? 

[kd7eir]

I'm currently using it to help me tune various long wire antennas as well as testing filters.

[joeqsmith]

Assuming you are using the 4.x rather than 3.00,  let me know if you find any problems with it.   4.02 should be fine.

Sounds like you are mostly playing around below 300MHz.  What drove you to buy the V2Plus or LiteVNA?   IMO, the original NanoVNA would have been a better choice.

[kd7eir]

I am using 4.02. I chose the LiteVNA because I plan to start setting up some microwave links in the Arizona - New Mexico area in the next year or so.

[joeqsmith]

If you start a blog post a link here.  I'm interested in reading more about it.

[kd7eir]

I will certainly do that.

[@rt]

I just got mine… the H version.
Has anyone written anything completely different for the device itself?

I previously had the Mini600, which was based on STM Discovery board,
and I did a plasma demo intro for it just for a bit of fun.

I haven’t looked into this one much. Are there any dramas compiling its source?

[joeqsmith]

I just got mine… the H version.
Has anyone written anything completely different for the device itself?
...

The thread is more about software that interfaces with the VNA, not firmware that runs on the VNA.   I suggest you join the group.io reflector for the NanoVNA and ask there.   Another group you may want to consider is for the firmware developers and beta testers.    Feel free to post here but I doubt you will get too many responses. 

[joeqsmith]

4.03 is now live.  This version will allow the LiteVNA to work with waveguides without requiring the frequency extender.  Obviously the Lite's performance isn't currently good enough to use for the X-band today, possibly in the future we will see an improved product.

When using the time domain functions with Touchstone imported files, some features were disabled.  These have all been enabled.   I don't normally import files, so this was more an oversight than anything.   Discovered when cat'ing files to measure some of those 1930s UHF connectors.   

https://www.eevblog.com/forum/rf-microwave/cb-and-ham-radio-techs-love-their-bird-wattmeters/msg5100693/#msg5100693

[Fred_B]

Hey Joe,

I've started using my VNA V2 Pro in measuring a hybrid coupler I am making. I noticed that the VNA is affecting the behavior of the hybrid, which is quite sensitive to impedance differences on its ports. Basically the problem is that the input impedance of the NanoVNA V2 is about 53.5 ohms as self reported by the device when a thru is connected between the cables after calibration.

I tried searching for some posts about this on other sites and the explanation I  found was that the nanovna has a frequency dependent return loss on port 2. The suggested solution was to add an attenuator to port 2 to force the return loss higher and stabilize the port 2 input impedance. This issue was said to be due to a lack of 12 term correction in the firmware/software.  So, I was wondering what you had to say about the issue and if the LiteVNA suffers from the same problem.

[joeqsmith]

Hello Fred,

All the software/firmware/calibration in the world isn't going to fix a hardware problem.   If your device is sensitive to the mismatch, about the only thing you could do to improve it is use an attenuator as suggested and give up some dynamic range.   The other option, throw money at it.   

What frequency range are you interested in working in.  I can take a measurement with the LiteVNA 64 I am currently using.  It is the latest revision of the hardware and has no modifications done to it. 

[Fred_B]

Rather than the sensitivity of my hybrid to the impedances presented to its ports, it's the VNA's self reported port 2 input impedance of 53.5 ohms that's my concern. That's 7% from nominal. I would like the port 2 input impedance to be within a tenth or two of 50 ohms. People have also mentioned maybe the cables or even the thru are contributing to that, although I have yet to read about anybody claiming that the cables or thru that come with the nano VNA to be anything other than 50 Ohms.

I'm presently dealing with VHF centered around 146 MHz.