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In an older publication of QST there was a TDR project. I made it and it works quite well for measuring electrical length of a coax and from that you can calculate the velocity actor. If you can find

I too was having the same problem of my NanoVNA-H not being recognized by DfuSe Demo. However, I tried ST's STM32CubeProgrammer. It was able to recognize the DFU device, and I could upgrade the

Try 0.66 and measure a piece of the same cable with a ruler and the VNA. Adjust VF until the two agree. If you can see the dielectric, use the VF for another cable with the same dielectric. Glenn --

How many answers need to be posted about this? I posted a link that gives the info for the most common materials used, including foam polyethylene and foam polystyrene. Zack W9SZ

Most *solid dielectric* cables are close to 0.66 Foam dielectric tends to be faster (because the Vprop is related to the permittivity of the dielectric, and foam is lower than solid)

You have no way to know, unless you make another measurement to compare physical and electrical length.

Not that there can’t be reasons for doing this (buying x feet of new coax to replace it with), but if you state the reason for wanting this measurement, maybe there’s a different way to solve the

Look at the end of the cable. If the insulation between the outer shield and center conductor is a hard and solid material the velocity factor will probably be 0.66. If this insulation is a soft foam

Here's more data: https://www.febo.com/reference/cable_data.html Zack [email protected]> wrote: <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_conte

Most of the commonly found cables have a velocity factor of 0.66. Zack W9SZ <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=icon>

You can only get a coarse idea of the length if you don't know the velocity factor. If you set the velocity factor to 1 (100%), you will get the electrical length of the cable, which will always be

What velocity factor would you use to measure the physical length of a cable when you don't know the cable type? Pat

Definitely not TVS because it can prevent RF overdrive according to the datasheet's "Power output vs. power input" graph. Diode based RF limiters utilize PIN diodes in order to minimize distortion.

David, On the early firmware versions you must short the BOOT0 pad to the VDD pad with a jumper at powerup to get into DFU mode. You can remove the jumper once the unit starts up. I think it goes to

David, The device should NOT be showing up on a com port when in dfu mode.?It should be under a different category called Universal serial bus devices in?also in device manager I had this happen

All good points, thanks! Gene Sent: Saturday, February 5, 2022 8:10 PM To: '[email protected]'<mailto:[email protected]> Subject: Re: [nanovna-users] Cannot Save screenshots to microSD

Gene, I find the screen dump to the SD Card is about 300K, S1P and S2P files are between 20-30K, so using the higher number for screen shots, about 50K files can be stored on a 16GB SD Card. I did the

I have an old nanovna, I bought it awhile back but now I need to use it. This software has no config menu item nor is the software version displayed anywhere. I have loaded defusedemo and the driver

I wonder how will much longer it will before they stop making 16 gig uSD cards, at least in a name brand. San Disk stopped making the 8 gig uSD cards that I used in my Raspberry Pi computers sometime

How many thousands or tens of thousands of images can be stored on a 16 GB card? Is there really a need for more? Get Outlook for Android<https://aka.ms/AAb9ysg> ________________________________ Sent: