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Dummy Antenna and FM Alignment
Hey everyone, True beginner in RF here for a classic alignment question. Sorry if this is inappropriate or the wrong group, I'm not sure where to ask such question. I suppose the NanoVNA would be a great tool to solve the question and you guys seem to know a thing or two about RF. I'm working on FM alignment for Citro?ns car radios from the late 80s and early 90s. For this I would suppose matching the alignment to the OE antenna and cable are ideal for best tuner performance and sensitivity. Therefor I also suppose it would mean making something such as a dummy antenna/aerial or a network so that the RF generator looks exactly like the antenna does to the radio, right? I have the cable, base and antenna of the car taken out. I also have access to a bunch of cars if averaging is necessary. My particular generator is 50ohm. I have no clue what the OE antenna and cable impedance are, as nothing is printed on them. Reading online it seems most automotive radio cable are 93 or 100ohms? For the extra information: there are two models I would like to align, a Blaupunkt which would have a 150ohm impedance, but the other which is a Clarion does not give any information regarding its impedance... it just says to plug the generator into the radio and voila. Thanks for looking into my question.
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Hello everyone, I have bought a NANO VNA H4 to build simple dipole antennas. Now I have made a simple dipole antenna for testing. This should be tuned for 172 MHz. The total length is ~83 cm (2,72 feet), one leg is ~41.5 cm (1,36 feet). When I now connect this antenna and try to measure it, the result is a lowest SWR (1.15) at 513 MHz. Can this be possible? I am not a radio specialist. I am an IT guy. I have flashed the NANO VNA H4 to the latest firmware (tried DiSlord and Hugen) and also calibrated it. Perhaps I need to make further settings after flashing?
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Hi DiSlord Coax Zc measurement function, already installed on H4 1.2.40 firmware, seems need to measure C0 capacitance @ 100Khz and the f0 first coax resonance frequency (Hz) and then we calculate Zc = 1/(4 x f0 x c0) Ohm , I appreciate it a lot. Can we do some accuracy correction ? indeed diélectric permittivity of polyethylene diélectric can vary with fréquency , it can decrease slowly up to -4.5% from 100Khz to 14.1Mhz for example , so we can correct C0 value by -4.5% and then ZC should be increased by +4.5% to be more accurate @ 14 Mhz Zc measurement . if our coax has 22.28 metre long with Vp around 83% , the first resonnance frequency will be around 2.71 Mhz wich still far from 14Mhz and may be some % error may be done , I prefer to measure the resonnance or antiresonance the nearest to the 14Mhz and devide by number for correction to have the more accurate Zc value based on measurement done as near as possible to the desired frequency .. What you think about all this view , or DiSlord has already taken in consideration all this possible corrections . 73's Nizar .
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NanoVNA H FW 1.0.53 Display Intermittent
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Have an old NanoVNA H with the above FW whose display is intermittent. More specifically, the menu turns off and on or will revert to the main menu. I have tried to do the touch cal and touch test with no success. Appreciate any remarks on the subject; resetting the unit, etc. Thanks in advance. -- William, k6whp -------------------- "Cheer up, things could get worse. So I cheered up and things got worse."
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I ran into a research paper on measuring capacitors using a VNA that might be of interest. It analyzes capacitance and ESR accuracy for the S11 reflection, S21 series-through, and S21 shunt-through measurement methods. The paper covers connector parasitics and fixture deembedding. Lots of useful graphs. https://doisrpska.nub.rs/index.php/electronics/article/view/1330/1237 Brian
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Jittery , non steady readings
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Is it normal for the readings to fluctuate as much as 2-3 ohms ? As in 11+/-1.5 - j(70+/-1.5) Dipole NMHA (antenna), balun, calibrated, two ferrites: one at the balun and one at the VNA S11 port. No body / coax inadvertent movements, everything taped down near the antenna. Thanks
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I buyed a nanovna H 3.6. When I try to calibrate it, after the full procedure, if I set a Smith diagram and I connect THRU the two ports using the supplied cable the value is 50 ohm instead of 0. I resetted and repeated the calibration a lot of time but with the same result. Can you help me? Thanks
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Electrical 1/2 wave.
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I have a NanaVNA-H4, And how would I use it to make an exact 1/2 wave or multiple there-of coax? 1/2, 1.0, 1.5, 2.0, etc... Joe WB9SBD
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NEgative resistance for S11 port antenna measurement
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Hello, v0.7.3 on Windows; Already had my nanovna calibrated in two range: 30 MHz around 315 and another 30 MHz around 434; used an average of 10 sweeps with ~saver which has produced some partly negative values for resistance - measured two (almost) identical antennas, without any in- ~saver calibration. I can say for sure that nanoVNA did not report any negative resistances. Having seen the failure, i have then set an interval from ~225MHz to 525MHz, some ~300 points, calibrated inside ~saver, remeasured the two antennas with generally different results, but still having ranges of frequency where the resistance was again negative. I have not properly checked what the naonoVNA was reporting on its screen for the frequency range. What am i doing wrong ? Thanks!
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New HW version 3.6.1 observations and questions
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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.
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Buying new VNA
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Hi guys, this is my first post here, I would like an advice to buy a new VNA, my main operation is till 50MHz, but eventually I can operate till 1.2GHz, what would be a good VNA to buy, H4; F; SAA. Can anyone recommend one. Thanks Nuno CT2IRY
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red LED no longer lights
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I have updated the firmware on my nanoVNA-H4 hardware build 4.3 using the NanoVNA-H.v1.2.40.bin file and STM32cube software, and notice that the red battery LED no longer lights when charging or unit is turned on. Same effect after I upgraded my TinySA Ultra....no longer red LED function. Is that normal?
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Running NanoVNA Saver (or other software) on Linux
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Have been searching the threads for this item and am wondering if.. (1) NanoVNA Saver has a port to Linux or can be run under Wine on Linux? (2) Are there any other NanoVNA software packages that run under Linux? Thank you in advance. -- William, k6whp -------------------- "Cheer up, things could get worse. So I cheered up and things got worse."
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Locked
McAFee Virus Scanner Objects to nanoSaver download from GitHub
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I've tried downloading nanoSaver to Win11Pro and McAfee snatches the .exe into quarantine. I'm using the github download: https://github.com/NanoVNA-Saver/nanovna-saver/releases I tried using a Win10 machine and nanoSaver runs, but MacAfee wants to remove a virus. Anyone got a clue on what is going on?
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* * * * * Multi-Band HF Vertical* * * *In an effort to get a VERTICAL ANTENNA up for the 20/17/15/10 meter bands, I tried setting up a 14 ft vertical antenna* *made from old aluminum tubing, mounted 3 ft above ground, adjacent to a 20 ft vertical aluminum rain gutter - mounted just inches from it for close coupling.* *Set up three radials - two were 13 feet and one was 33 ft. **No matching of any kind.* * * *Results were surprising as the rain gutter makes this vertical into a reasonable multi-band vertical for 20/15/10 meters. * *Cost was almost nothing.* *Fed with 50 ft of RG8X and a coax choke at the input to the antenna terminal.* *I'll have to try it out this weekend on 20/15/10m digital and see if it radiates a low-angle DX signal.* *de k3eui barry*
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Hello, new to this group. I've learned a lot from reading here, but i seem to have run into some issues and could use some advice. I'm building a low pass filter, and trying to learn to measure inductance using the nanovna. I've built a test rig that I found on one of the threads here somewhere- three pieces of double sided pcb for OSL, and I'm soldering my air core inductors to that. I'm trying to use the S11 shunt method for a coil that needs to be 72.4nH. Ive got a couple things I'm not understanding- should my coil be adjusted for the necessary inductance at the frequency for the filter of 50-55mhz? And does it need to be adjusted for impedance at that band as well? I've attached photos- my 90deg phase and 50 ohm mark is at 112mhz, but this inductor is for the 6m filter. Another thing I'm not understanding is the 5khz self resonance dip seen at the beginning of the sweep, shouldn't it be reading capacitive since it's after the phase reversal? Any help is appreciated
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Apologetic Intro Message
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Just joined and here goes my newbie message. Sorry. (1) I have an H4 from 2020 with the 0.5.0 FW version. I am guessing that an upgrade would be in order? (2) Also looking into an "F" and saw some being sold on AliExpress for 102.93 marked down from $205.86 (50% off) ..is this a reliable source and product (link below) or, in not, what is reliable? Thank you in advance. -- William, k6whp -------------------- "Cheer up, things could get worse. So I cheered up and things got worse." https://www.aliexpress.us/item/3256806945598446.html?spm=a2g0o.productlist.main.15.7d601593PWjk7F&aem_p4p_detail=202503180111544540975407725520000030587&algo_pvid=db65f088-f2d8-475b-a4b2-eb0ecb9c50a0&algo_exp_id=db65f088-f2d8-475b-a4b2-eb0ecb9c50a0-7&pdp_ext_f=%7B%22order%22%3A%221%22%2C%22eval%22%3A%221%22%7D&pdp_npi=4%40dis%21USD%21205.86%21102.93%21%21%211480.98%21740.49%21%40210312d517422855142704518e4a59%2112000039530167557%21sea%21US%213368703417%21X&curPageLogUid=2arQ5G1GtJBb&utparam-url=scene%3Asearch%7Cquery_from%3A&search_p4p_id=202503180111544540975407725520000030587_2
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Hi, Is my setup ok ? Is there any monstrous mistakes in my montage ? I'm quite new to the nanoVNA. Well, I am totally new on VNAs themselves. I did not know their exitance 2 months ago ! Well, I want to match my antenna because so far, it is pretty horrible. But, before ordering some matching network component and then screwing everything because I am missing something obvious, I would like someone to point me to the rookie mistakes I could have made. The project is a LoRa module (902-928MHz) connected to a small antenna mounted on a pcb. The pcb is inside a small polycarbonate box. I have followed the design rules for this antenna from the manufacturer. I have calibrated my nanoVNA-F V2 (from sysjoint) using the supplied calibration set, straight at the S11 connector. My board is inside its final box and mounted on a wood plank that mimic the final location. My board is hooked up to the vna through an RG-174 I had laying around. It is 2 meters exactly. I have added an E-Delay of 10.1ns as per a calculator I found on the Times microwave website. I don't know if there is a bug in the vna's firmware but I had to put 0.66 as the velocity factor in order to make it display 2.00 meters as the cable length. If I put 66 as in 66%, it shows 200 meters. Anyways, I'm not sure if that part is that relevant. So, by looking at the pictures, does anyone can see some obvious mistakes ? Thank you so much
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New user (owner) of Nano VNA
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Hey guys just got a nano VNA. it is a "seesii, nano VNA-H. I need some help in setting it up to see the SWR on some antennas. I have gone through the various manuals and the one that came with it, and I am very confused. Basically what I am looking to do is (to me ) very simple. Input a start frequency, lets say 144 MHz. A stop frequency, say 152 MHz. The see the lowest SWR point as an inverted bell curve. Anyone have any ideas how to do this? Also, I cannot seem to find the correct software for the device. I know my cable is good (as I can get data off my cell phone with it) but i cant the nano VNA to be recognized. Please help. Howard
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What we can do more with TinySA ultra
4
Hi As a hamradio operator what can i do better with TinySA ultra then NanoVNA H4 ? What kind of measurement with TinySA can be really usefull for antenna, filtering .. around hamradio activity , did sdrplay spectrum display can replace TinySA on moste cases ? i see that it has a handy signal generator but what really much important to do with? 73s Nizar
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Sat 8:39am
Sat 8:39am