I recently replaced my MCU on my old NanoVNA H v.3.4 board. I was able to flash the latest Dislord firmware onto the MCU via DFU and it loads up. However, it is frozen on startup. No input on touch or jog wheel. I have replaced the MCU with another one I had to see if this made any difference - none. The jog wheel switch is working confirmed by continuity test along the VDD to pins 11, 12 and 13. I have tried downgrading to a more recent version but that doesn't work either. Any other suggestions of where I should look either on the board or in firmware to try to assess? I like this NanoVNA for sentimental reasons - I have used it since I was a Foundation call and have taken it everywhere with me portable ops.

*Now down to two HF antennas at new QTH at Crosslands Retirement Community (Kennett Square) SW of Philly* * * *Still have major high noise level from 1-10 MHz and working to solve it. * * * *1) NVIS horizontal end-fed 135 ft - tunes up easily on low end of 80m/40m/20m/ 17m/15m/10m* * SWR about 2.5:1 on 30m band, but I have a Hustler mobile antenna for 10 MHz band * *2) Vertical (made from old Cushcraft A10) 16 ft with home-made matching coil at base: covers 20/17/15 meters for low-angle DX with a few radials * *Both antennas doing well, catching signals from all over the world on the vertical.* *Horizontal wire is doing well on the NBEMS regional nets on 80m and 40m.* de k3eui barry

I've used my NanoVNA-H4 periodically for several years. Yesterday I charged it, then upgraded the firmware from NanoVNA-H4-SI_20211230 to NanoVNA-H4-SI_20211230. I re-calibrated and started doing some testing with it apparently working fine. I got distracted for a few minutes, and when I checked the screen was black. I powered it off, then back on, but the display only appeared for a second, then went black. Since then when I turn it on I see a normal display for approximately one second, then it apparently shuts off. Things I've tried, none of which have made any difference: * Charging it, including overnight. * Powering it on while plugged into a charger or USB port. * Disconnecting the battery for a while, then reconnecting it. * Powering it from USB with the battery disconnected. I wanted to try re-flashing old firmware, but it appears to do the same thing in DFU mode. When I power it on while holding the multifunction switch, I see the following in dmesg on Linux, and dfu-util doesn't see it: [385834.014786] usb 1-3.4: new full-speed USB device number 39 using xhci_hcd [385834.104077] usb 1-3.4: New USB device found, idVendor=0483, idProduct=df11, bcdDevice=22.00 [385834.104090] usb 1-3.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [385834.104096] usb 1-3.4: Product: STM32 BOOTLOADER [385834.104101] usb 1-3.4: Manufacturer: STMicroelectronics [385834.104105] usb 1-3.4: SerialNumber: 205E33642031 [385835.056995] usb 1-3.4: USB disconnect, device number 39 Any suggestions of other things to try? Thanks, Jim

Hallo, I need help, I only need this instrument to measure the length of the cable and where the cable is open. If possible, I would measure rg6 and rg11 75ohm, the longest length up to 10-30m I have set everything, but I don't understand what values ​​to type in the option STIMULUS FREQUENCY. Thanks everyone for your help

Another experiment. What difference does the NanoVNA CALIBRATE>POWER setting produce in the VNA’s signal level? The Setup: VNA S11 calibrated to start/stop of 50 MHz–90 MHz, 401 sweep points. Traces are LOGMAG & Smith. TinySA Ultra set to start/stop of same values as VNA. Attach 30db external attenuation to SA and set LEVEL>EXT GAIN to -30db so what you see on the screen is the true current the VNA is sending. Set VNA to CW mode at 60MHz, leaving CALIBRATE>POWER on AUTO. Then freeze trace 1 (yellow). Set VNA CW mode at 70MHz, . Activate SA trace 2 (green). Set VNA CALIBRATE>POWER to 2mw. Freeze trace. Set VNA CW mode at 80MHz, CALIBRATE>POWER to 8mw. Activate SA trace 4 (red). Freeze trace. Activate 4 SA markers. Set 1, 2, & 3 to trace 1, 2, & 4, respectively. (ignore marker 4). What happens? The VNA CALIBRATE>POWER>AUTO produces the same signal as CALIBRATE>POWER>2mw. AUTO is the same as the lowest POWER setting. A good design choice for safety’s sake. CALIBRATE>POWER>8mw is higher by almost 10mw than AUTO/2mw. If you look at the marker values at the top of the TinySA screen, you see that they are just as expected within the resolution of the SA. Notice all the spurs around the highest power (trace 4) setting. In the pictures, the SA’s LNA is OFF. If I turn it ON, both the AUTO and 2mw traces also show spurs though smaller than those produced at 8mw. Picture 1 of both devices Picture 2 a close-up of the tinySA I hope clear enough to read the marker values Picture 3 is just a shot of my best (and most expensive) little attenuator: Pasternack, 30db, 2W.