Hi, all, I got a reference to this in my email today. It's a great description of how a Smith Chart works and how to use it for various measurements. If you're not familiar with complex numbers as applied to impedance, it's in the form of 50 +j0 where the 50 is the resistive impedance and the j figure is the reactive impedance (+ for inductive, - for capacitive). So 25 -j10 would have 25 ohms resistive impedance and 10 ohms capacitive impedance. 50+j0 would be a pure 50 ohm load. https://www.electronicdesign.com/technologies/analog/article/21167514/electronic-design-impedance-matching-basics-smith-charts

Has anyone else noticed constant signals even after calibration? These are either positive or negative depending on the measurement that you are taking. The first is at 300.042500MHz The second at 460.038500MHz This is on a NanoVNA-H4 V1.2.29 Whatever I have tried has made no difference. (I have not changed TCXO, Threshold or IF OFFSET values). I am sure that there is something obvious that I have missed, but for the life of me I cannot think of it. Paul

I have four RG-58ish cables around, of varying length and pedigree. I decided to measure the losses with my NanoVNA in the HF and VHF/UHF bands. Results were not shocking, the high quality LMR-195 cable was the best, even though it's the longest of the bunch. Two other cables of unknown history didn't perform nearly as well. Losses increase with frequency. I also tried re-running the HF measurements with a saved calibration file, to see how much drift there was. It wasn't zero over 30 minutes, but it wasn't bad, either. I posted the procedure and results here: https://drive.google.com/file/d/15XKHUNggS2VFGRSs4pt2NZI6QuhMM7HR/view?usp=drive_link

Hi all, I just upgraded my H4 FW from v 1.2.20 (Mar 12, '23) to the latest I found, v 1.2.29 using DFU, but the device still indicates no change in version (v1.2.20). Am I missing a step or something... TIA

Hi - nanoVNA-H4 - Blue light on all the time. Had NanoVNA.H4.v1.2.29 so downgraded to NanoVNA.H4.v1.2.29 just to try but still the same - Any ideas? We are going to disconnect and reconnect the battery to see if a hard reset works, still going to look inside if that is easy to do.

Just purchased a nanovna-H. I’ve watched 5 video presentations on how to use it for antenna and choke evaluations. Watched one guy show how to program it and got totally lost. I have no idea how to update the software, as I’m old and not programming savvy at all. Any good reads online or in a book for learning the basics? Thanks, Bob

The following scenario and questions is based upon the fact that my mind, never particularly bright or dim, has aged well past its prime. I have a Nanovna H4 that I cannot influence to communicate with three different Windows 10 PCs. Some 18 to 24 months ago, I upgraded the firmware, and since then it has worked as I chose - without any device other than the occasional use of an external "Li power pack" attached to its usb c port. Today, my Tinysa reads and writes with the same PCs. None of the various methods I am aware of, suggested on or off this group, has produced any recognizable evidence of data flow between my Nanovna H4 and my PCs. Is there a "simple" method, such as the use of a terminal program like PUtty, to determine if my Nanovna H4 is truly deaf and dumb? If a terminal program will work, what command strings would I use, and what expected results should occur? TIA, Da Ol' Dog/WA4HEI

Wow - can this get any more frustrating? I have a SV4401A VNA that works fine, so I thought I try to get the severe VNA server software to connect it to on my Mac mini Intel. And that is where the fun begins. I wound up installing it via MacPorts, which had been on my Mini since a year or so ago when I installed PuTTY. It appears that the Saver install ran properly. But now what? Looks like the application was installed in the MacPorts folder. I double click on it and... nothing happens. I look in the Activity Monitor and it is not there. Down on the bottom of the Mac screen sits the icon for it, but it does nothing. The SV4401A is powered on and IS connected to the Mac. How the heck does one get the NanoVNASaver program running? -- Jim / K7TXA Eagle, ID

hi all,i am new to this ad have a few questions. 1. i have see various pics with SWR showing 250m or 50m or 10m... how do i change between these numbers? 2. after i have tested my Swr of my antennae, how can i save these readings, ( for various Frequencies) and be able to send to someone else for viewing, or simply save for future reference? thanks for responces de j73esl

I have some questions about how to use xnec2c. For example, what units are used for wire diameter? Meters? Millimeters? Is there a better antenna simulator for Linux?

I have an older NanVNA-H presently running 1.2.14. I would upgrade it to 1.2.27 if I could figure out which DFU file I need. Clearly, the -MS variant is for the newer units, which mine is not. Likely, I would use the –SI variant. However, there is also the –SM_ST variant. What on earth is it? I can not find reference to it anywhere. Could it possibly apply to my unit? Bill AB6OR

There is a new HW version being sold now. I purchased my unit from one of the recommended sellers on the NanaVNA site. (Aursinc on Amazon) The new version has a different clock generator SMC5351A. Not sure how it compares to the original Si5351, or the supposedly better MS5351. (I know the switch to MS5351 was de to availability, but it was claimed that it had slightly better performance over the Si5351) I had a lot of trouble finding any info on the new chip, and no proper data sheet. Did find a little information, but not enough to do any comparisons, and I am not an expert in this aspect anyway, so subtle differences would be lost on me. Not sure why the change to this new part, as it forks the FW to yet another version, and this particular nuance of the FW update process is not well documented. Not even any of the newer instructional videos online mention it. The fact that the documented application DFUSE has been replaced by STM32CubeProgrammer, and also that the new DFU driver does not work with DFUSE is also not documented. I was able to do the FW update using the same method as the TinySA... Which also does not work as various instructions online show. I must use the "Full Chip Erase" command first, then load the new FW onto the device, otherwise the unit will not boot. This posed a problem for me, when I attempted to update the FW to the latest DiSlord version. The unit booted, but the screen was jumbled. After loading the SM_ST version from hugen79, things are back to working. This FW is a version behind DiSlord's, so hopefully they get an update for this new HW revision soon. The only question I have now, is which mode under Expert Settings I should use. MS5351 or Si5351 It appears to default to MS5351, so that is probably what it should be set to.

Hey, I've got a NanoVNA (either a pre-H clone or version H). When I try to hook it up to a computer (tried with Mac and Linux), no serial port via USB is found. When I put it in DFU mode, everything works fine and I can flash the device. When I hook it up to Linux and run dmesg, I see the following messages: [ 156.676696] usb 1-1.4: new full-speed USB device number 27 using dwc_otg [ 156.776755] usb 1-1.4: device descriptor read/64, error -32 [ 156.996720] usb 1-1.4: device descriptor read/64, error -32 [ 157.216713] usb 1-1.4: new full-speed USB device number 28 using dwc_otg [ 157.316713] usb 1-1.4: device descriptor read/64, error -32 [ 157.536694] usb 1-1.4: device descriptor read/64, error -32 [ 157.656925] usb 1-1-port4: attempt power cycle [ 158.316730] usb 1-1.4: new full-speed USB device number 29 using dwc_otg [ 158.756690] usb 1-1.4: device not accepting address 29, error -32 [ 158.856703] usb 1-1.4: new full-speed USB device number 30 using dwc_otg [ 159.296790] usb 1-1.4: device not accepting address 30, error -32 [ 159.297308] usb 1-1-port4: unable to enumerate USB device [ 163.946824] usb 1-1.4: new full-speed USB device number 31 using dwc_otg [ 164.046848] usb 1-1.4: device descriptor read/64, error -32 [ 164.266833] usb 1-1.4: device descriptor read/64, error -32 [ 164.486885] usb 1-1.4: new full-speed USB device number 32 using dwc_otg [ 164.586898] usb 1-1.4: device descriptor read/64, error -32 [ 164.806837] usb 1-1.4: device descriptor read/64, error -32 [ 164.927061] usb 1-1-port4: attempt power cycle [ 165.586867] usb 1-1.4: new full-speed USB device number 33 using dwc_otg [ 166.026856] usb 1-1.4: device not accepting address 33, error -32 [ 166.126870] usb 1-1.4: new full-speed USB device number 34 using dwc_otg [ 166.566855] usb 1-1.4: device not accepting address 34, error -32 [ 166.567159] usb 1-1-port4: unable to enumerate USB device Initially I thought this may be because I was connecting it to a USB3.0 port, but the message above comes from a Raspberry Pi with USB 2.0. Has anyone had a similar problem?

This measurement was motivated by another post within this group. So..... here goes...... I frisked my NANOVNA H4 with a magnetically coupled 2.5-inch (6.35 cm) diameter single turn probe using the Rigol 815 spectrum analyzer. In short, I was amazed. I've tested many...MANY.....other produces far.....FAR......"dirtier" than the NANOVNA H4! I'd estimate it would even pass FCC Part 15 for an unintentional radiator. However, the two ports to which one connects probes, antennas, or other equipment are quite "dirty" with many closely spaced tynes. I suspect if one kept the coax connecting to/from those ports to an absolute minimum, the radiated RF problem would be minimized. Both ports - just the backshells - are pretty hot all the way to 1.5 GHz. With nothing connected to either port, the unit is pretty clean by my estimation for radiated emissions. Now, let me hang a couple unterminated coaxial cables to the H4 and have another look. Roughly 5-foot (152 cm) of RG-58 unterminated cables are attached to each port. The NANOVNA H4 is placed on my very "busy" electronic work bench. The receive antenna is a 38-inch (96.5 cm) diameter single turn loop supported in the radio room window. It is directly coupled to the Rigol 815 SA. For the results, have a look at the attachment. With cables attached, not so clean! However, one may reduce these emissions by clamping several ferrites on the cables at the H4. Nuts. I tried it with several 43 material ferrites. It didn't do much at all. Oh well..... My conclusion is that without anything connected to the SMA ports, it's pretty clean. With anything connected to the SMA ports the radiated emissions may offer a challenge to low-level relatively open-air measurements. Dave - WØLEV -- Dave - WØLEV

When I download the supposed precompiled code from nanovna.com/?page_id=141, all I get on the screen from the download is a bunch of gibberish (to me). How and where do I obtain a usable code for nanovna-app? Dave - WØLEV PS: I'm no software type, so be kind, please. -- Dave - WØLEV