New Nanovna user and first time posting, so hi everyone! 👋 I have a NanoVNA H4 running firmware 1.2.29. For my first project I'm putting together a delta loop antenna for the 4m amateur band. I took some initial measurements and I'm slightly confused about what I'm seeing: Return loss of -7.9dB at 71.000 MHz, SWR of 2.3 to 1 at the same frequency and smith chart impedance of 21 ohms. I've attached some screen shots to show what I mean. First of all, I'd have expected to see a greater return loss of the loop is truly resonant at 71.000 MHz. The SWR is about what I was expecting, because the characteristic impedance of a loop antenna is typically somewhere around 100 - 120 ohms. The smith chart, however is showing the impedance as 21 ohms. Could these results simply be due to the DUT being something other than a 50 ohm impedance? I did make sure to do the OSL calibartion before I started. Any tips and suggestions would be gratefully received. 73, Phil, G1BCG

Hi, i am building some all-pass networks(90deg phase shift networks) and need to measure some 10nF capacitors to get the closest ones. My question is: what is the nanovna accuracy at measuring capacitors? i am using this method: https://youtu.be/iJ1qKE5O0bY?si=2Ey7KooH_A4wg-rO&t=592. I also have a Aneeng AN8009 multimeter which has 0.01nF resolution and a accuracy of +/- 2.0%+5 at up the 99.99nF range. So, which should be more precise at measuring the 10nF capacitors for the phase shift network? Thanks, 73 DE PP2GS

Newbie here. I am interested in testing antennas for resonance and swr. 80m to 70cm. Both indoors and outdoors. I was thinking of buying an entry level antenna analyzer. Several helpful people suggested getting a nanovna instead as it was said to have a cheap price ($60ish) and extensive capabilities. After reviewing Amazon and eBay for nanovna I don't see much in that price range (at least double and more) and I sense from reading material here and there that there will be a lengthy learning curve with no guarantees it will work for you. Plus it's not obvious which one of many nanoVNA offerings to buy with all sorts of illegal clones and firmware issues abounding. Not really like that with store bought antenna analyzers -Price and features laid out. An I missing something?? Appreciate input. Edward

Hi all, I'd like to first start out that I am a noob to nanovna, but not pc's in general. I'd like to think I know my way around a PC. Love it or hate it, I'm currently on Windows 11. Trying desperately to get this thing working using Nanovna-APP or Nanovna-Saver. The device I currently have is a NanoVNA-H in a white case with a lizard on it, running Version 1.2.14. Architecture: ARMv6-M core Variant: Cortex-M0. Platform STM32F072xB I have followed the absolute beginners guide to finally get the STM driver link. I downloaded and ran the Windows 8 x64 driver installer. After doing the install, I am getting the a driver install issue (see image 1). As a side note, I tried other cables, tried booting into dfu mode, and I get the following driver note (see image 2) I also tried a Windows 7 pc and am also having a bit of a headache trying to get it to work. Any advice on what to do here? Feel like I'm bashing my head against the keyboard and getting no where.

Drove me crazy until today! Pushed and turned repeatedly to locate and select. Never made any sense so today hosed it doen with old Radio Shack control contact cleaner. Now the durn thing works really well! -- 73 Karl KI4ZUQ

I've made a web search for using VNA's to measure velocity factor of cable and it looks like there are 2 methods and some online calculators. There is a youtube showing the NanoVNA and it indicated a potential 2cm length error. What I'm trying to determine is an unknown spool of 300 ohm twin lead. I'm guessing it can be anything between 82 - 88 vf. (My end application will be some roll up 2m slim jims. ) I'd like to figure the VF as close as possible - anyone have practice measuring twin lead? Andy

KB2EE here, evaluating ferrites for use as HF CM chokes on coax. I read K6JCA's excellent notes on the reasons to avoid single-port (S11) measurement of R+jX - the method can be inaccurate (especially resonant freq error) due to unaccounted-for capacitance between the DUT and instrument chassis. So I set aside my Rig Expert A55 and decided to use my NanoVNA-H4 in S21 mode. Before considering my collection of ferrites, I did a sanity check of NanoVNA S21 results using reliable RF "pure-R" loads. I constructed the typical test setup of 6-inch RG-316 SMA extension cables to a rigid metal plate and alligator clips for connection to the DUT. The test loads are a 1% 150-ohm surface mount resistor and a 1% 50-ohm surface mount resistor - mounted on a short and narrow strip of copper clad board with a little gap for the resistor. They read 150.0 and 50.0 at DC and should be very near that with minimal reactance at low HF, such as say, 13 MHz. After calibrating (SOLIT), the nanoVNA-H4 S21 reading for the 150-ohm test load at 13 MHz is .428 + j.023, which translates to Z = 133 - j1.8. The X is properly negligible, but the R is in error by -11%. Ironically, the S11 result yields 149.8 + j0. The 50-ohm test load at 13 MHz S21 reads .686 + j.027, which translates to 46 + j1.34, an R error of -8%. Ironically, the S11 result is 49.9 + j0. So I bought a replacement NanoVNA, but mistakenly ordered the mini-version, the NanoVNA-H. No big deal, at least it's brand new, and now my sample size of NanoVNAs is up to 2. Ironically, the new VNA shows similar S21 error in R measurement, just as gross, and in the other direction! The 50-ohm test load at 13 MHz S21 reads .642 + j.024, which translates to Z = 56 + j1.65, an R error of +12%. Yuck! For the Fair-Rite solid cable cores (large beads) that I am evaluating, their typical R at their HF resonance will be 50-160 ohms, so S21 R-result errors like this are disturbing, especially considering that the supposedly less-trustworthy S11 results seem to be very accurate. In checking some of my ferrite cores, the NanoVNAs do indeed show S21 R results that are considerably low, compared to Fair-Rite data sheet numbers. The ferrite resonance frequencies indicated by NanoVNA's seem accurate, but their R errors are disappointing, and I am especially bothered by the two instruments showing large and divergent R error. I would expect that the more elaborate S21 (vs. S11) measurement would be more trustworthy, but all indications here are that just the opposite is true. I wonder if any helpful ops out there could dupe this experiment.....being particularly careful to use loads of near "pure-R" (at least at HF -like these surface mount resistors). Yes, I know that these little devices are not $60,000 Hewlett-Packard instruments, but cruder instruments (you know who) which I have used over the years never showed such errors at friendly (low) test impedances like 150 + j0 and 50 + j0, and at HF, no less. Just about any device should get those pretty close, and with thousands of man-years of these thousands of NanoVNAs out there, I have not run across any complaint about this particular issue - yet I see it clearly the first time I try it......and it appears on two(!) of these widgets. Anyway, these Nano's do okay in S11 mode.......so why the gross-out in S21? Tnx, vy 73........ "Perturbed in Henrietta"........Larry KB2EE

Some time ago I built a toroidal common mode choke, but was not happy with the performance. Having found a procedure by W0LEV to evaluate it, I made the test jig and ran the tests. In addition to the common mode test, I ran a throughput test and an S11 (only) test with a 50 ohm load on the other end. Photos of the setups and results follow. Is there anything I can do to the choke to improve its throughput performance? The SWR and impedance rise linearly with frequency, with a loss of over 8 dB on 10 meters. CM Test setup: Choke2 CM Test setup.png CM Test results: Choke2 CM mx.png Throughput test setup: Choke2 Thru test setup.png Throughput test results: Choke2 thru.png 50 ohm load test results: Choke2 50 ohm load (If higher resolution photos are needed, I can provide Dropbox links.) 73, Neil