On Thu, Oct 10, 2019 at 12:00 PM, <hugen@...> wrote:
I have checked the parameters of RG174 and RG316 cables. They are not ideal at 1 GHz.
You're right. I got NanoVNA from your store and rg174 which come with your NanoVNA definitely has less than 75 ohm impedance. But it is also definitely higher than 50 ohm. See TDR step response in attachment. It looks that the real impedance of this rg174 is about 55 ohm.
Obviously it would be better to use RG405 or RG142, but they are too
hard and not suitable for portable devices. If you use it in the lab, I
recommend using RG405 or RG142 cable.
I agree these rg174 is not best for precise measurements, but their quality is acceptable for usual amateur measurements, such as antenna and filter testing, etc.
And I also agree, rg405 are too hard for typical usage, so these rg174 looks like best choice for nanoVNA kit. They are flexible and not so bad, they have acceptable performance for typical amateur measurements.
Regarding to the cal-kit which you selected for NanoVNA, I'm not sure about S and O quality, but L load looks very good, my instance has 49.95 ohm and pretty flat response. It is better than other dummy loads that I got from China.
Thanks for the good-chosen accessories.for your NanoVNA kit. I'm satisfied with it :)
There are two minor issues that I found in your NanoVNA:
1) joystick quality is not good, it is very weak, I got one that has false triggering when you turn it right side.
2) shielding quality is not the best, it is like hand made, but it works after all
So, if you're planning for a new issue for classic nanoVNA, please replace that joystick with something else, for example with buttons.
