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Hello everyone! I managed to brick my nanoVNA H (clone, as I've found later on this forum) and now it is showing a white screen. First of all, I should have read this forum before the purchase and buy the real thing, but the product looked legit at the first glance. Second, I should've made a copy of the initial firmware before I install the new one. But what is done is done and I'm looking forward for a posible solution. Do you know what firmware came with this thing in the first place, to help me roll back? Since it is a sofware problem I imagine it can be done, but the seller didn't provided his support. Thank you! There are some pictures with the front, back and inside the nanaVNA.

Hi, I am trying to get to grips why I am not getting the same Smith Chart results with my NanoVNA as I am with my DG8SAQ VNA. I have got to the stage of trying to make everything as simple as possible. I am using the same connectors, cables and calibration standards. To make things even simpler I am just using a quality HV mica capacitor which measures 442 pf. According to Pasan software this should be 0 -j50 ohms at 7.2MHz. When I use the DG8SAQ VNA I get milli ohms -j46 ohms, which to me is close enough. Using the NanoVNA with an identical setup I get 11 ohms -j49 ohms. Which is pretty useless. What is going on ? T.I.A. Stewart G3RXQ

* RAIN GUTTER ANTENNA on upper HF bands* * * *I've been experimenting with a variety of HF antennas here at my new QTH at Crosslands Retirement Community in Kennett Square, PA. * *I have some space limitations, but live on the first floor of a two-story apartment building.* *Lots of RFI from everywhere inside the building - S9 on 80m and 40m, less noise on 20 and 10m. * * * *I have a 140 ft end-fed wire with a 49:1 UNUN which tunes up easily on 80/40/20m and not so well on 17m/15m/10m.* *This end-fed is horizontal, low to the ground (winds among trees) and is good for high-angle NVIS radiation on 80/40m.* *I use it on the PA NBEMS net (3583 kHz) and on the Mid-Atlantic NBEMS net (7068 kHz) * * * * * *I'd like to get up something with a _low-angle_ signal for DX on 20/17/10m bands. * *But can I keep any HF antenna "hidden"?* * * *What I am now trying is the aluminum _rain gutter_ for our building, vertical for about 20 ft, makes a right angle turn and runs horizontally for about 20 ft.* *The coax attaches at the base of the gutter, near ground, to a 9:1 UNUN with a sheet metal screw into the gutter for a decent electrical connection. * * * *So overall, about 40 ft of thick (painted) aluminum gutter radiating element - in the shape of an inverted L and not resonant on any ham band.* *Lowest SWR around 16 MHz. It looks like it might work out on the 30m band as well (10.1 MHz). * *I have a Palomar Engineering (500W rating) 9:1 UNUN on 50 ft RG8X coax into the shack (closet).* *I have one counterpoise wire about 20 ft long attached to the UNUN ground terminal.* *Then a good manual tuner in the shack to an HF rig for very low SWR on any band. * * * *Here is what I see on my Nano VNA from 10 - 30 MHz: not bad SWR (under 2.5:1) in the shack on 20/17/15/10 meters.* *I'll give it a try over the next few weeks and see if the local noise is more/less on these bands, compared to my 140 ft end-fed.* * * *I'm often running QRP on these bands, CW and digi modes only. * * * *de k3eui barry*

problem started when i attempted to upgrade, screen went black, foolishly did not save the old version.. now i can read the vna with stm32, it even appears to write the new firmware but still a black screen, how do i know if i am using the correct firmware for my vna? what are the correct steps to read and program with stm32? i must be missing something, any help would be appreciated. thanks for any advice Bob VA4BG

Hi, Currently trying to design and tune a 1/2 end fed antenna (RF is applied on one end), I am looking for the correct method to measure its impedance. As this one is very high I don't know the right méthode ! The result of this measurement should allow me to create a Stub with SimNEC to tune it. Thanks in advance for your help -- 73 s Christian F8GHE

Since most filters are a series of resonators of some kind or another, terminating them in a resistance other than the design resistance will probably change the filter characteristics. Consider a filter that effectively has an input that is a RLC circuit, where the R is the terminating impedance of the source. If you change R from, say, 300 ohms to 50 ohms, then the Q will be different. That will certainly change the skirts, and will also probably change the overall passband (since most filters are stacked up responses of multiple resonances).

Folks, Using the NanoVNA as a signal source for Ground Penetrating Radar (GPR) was discussed a couple of years ago. Today on Hacker News, there is an article about a home-built Synthetic Aperture Radar (SAR) unit using a freq around 6GHz. https://hforsten.com/homemade-polarimetric-synthetic-aperture-radar-drone.html The article discusses theory and the problem of finding a suitable Rcv A/D. The LiteVNA has the freq range, is capable of resolving nS time (to a certain amount), can measure phase and is programmable. The big issue is probably the switching time of the generator/reflection ICs in the front-end of the LiteVNA. As for the A/D spec, would the heterodyne method and DSP used be a limiting factor? So - might it be feasible to make use of the LiteVNA in a simplified radar setup using an external controller and appropriate antennas? Could the TDR routines be adapted? Could the LiteVNA be used with a TinSA-Ultra and a controller for something? Just thinking out of the box here. In my 60+ years of Tech, I have always looked at repurposing stuff. So, instead of "not possible" answers, I would rather hear what might need to be changed (electronics /software) to achieve a minimal proof of concept. Thinking caps on.... ... Larry

I am a new NanoVNA user. Mine is an H v3.6. No firmware updates have been done. I have been using it only for a few days. Sometimes, on sliding the switch on, the screen is blank, but the blue LED is lit. After a few on/off cycles, the screen becomes functional and I can use it. Does any of you have a similar problem? Jon, VU2JO