开云体育

Also ensure that the cable that you are using is a data cable and not just one capable of only supplying power. Many cables can only supply power unless specifically stated, so I use a cable tester to

NanoVNA Saver does not touch your firmware so it could not have damaged your device. Your device cannot be "bricked" because the DFU loader is built into ROM on the microprocessor. Does your device

Nico, You mentioned that you are just starting off with RF design. You have picked a difficult starter project because at 900 MHz. there are many factors that come into play that are not big issues

Mine is not seen by Win 10 device manager. ( tried 2 cables and machines) I heard there is a way to get it out of DFU mode internally? Mine did not die updating firmware, but it was hooked up to PC

The feedline is still part of the antenna. The best you could do with this setup (the first image) is to decouple immediately after the SMA connector (ideally before the connector). 61 or 52

One way might be to use a transformer. ?Minicircuits has small, inexpensive transformers in a DIP package in ratios up to 16:1 or 25:1. 1:25 CORE & WIRE Transformer, 0.02 - 30 MHz, 50? |

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

I recently wrote a program to renormalize S-parameter impedance. This lets you measure a filter with a 50 ohm VNA even though the design impedance is higher. In the course of testing the program, I

Wow ! Thank you so much to every one for taking your time in helping me. I truly appreciate it. @Siegfried @John I finally did it. I've cut down my RG174 down to the shortest length I could (35mm).

And also remember line lengths on/in the dielectric are shortened by the reciprocal of the SQRT of the dielectric constant (I assume FR-4?....nominally 4.2). Dave -

Nico, A couple of points to consider. 1. I can't tell from your PCB photo if you had tracks on both sides of the board in order to implemented a transmission line from the matching network to the

I don't know that shortening it even more makes all that much difference. You can guestimate the loss and to a first order, you're looking for reasonably flat S11 across your band, right? So if 174

Let me apologize if my yesterday's post was not clear. The pictures I posted are actually the result of the recommendation you gave me. I took a 30cm RG-316 cable I have and calibrated at the very

Putting your hand near the antenna (or, really, anything) will also "load" it with a lossy medium, improving the match. As noted before, though, most people do this by using a tool to design it (e.g.

1) Do you have the eval board? (Always useful to look at a "known good" implementation) 2) I'm not sure it's expecting copper under the coil. The figure in the data sheet sort of looks like only the

Yes, you're on the right track. However, I'd strongly recomment you place several appropriate clamp-on ferrites on your feedline right where it exits the assembly. Also place a few at the VNA,

you should albsoutely calibrate on cable end and use one as short as it is practical (just a few inches would be best!!) only THEN you have exact values to type into simsmith .. then calculate parts

John, Thanks once again for the precious advices. As I’ve put the antenna exactly as I t has been manufactured, could I simply populate the matching network instead of stretching the spirals ?

Nicolas, Your results actually look pretty good. An SWR of 2.4:1 represents a loss of only 17%. Small changes in the spacing of the turns on your antenna should enable you to put the minimum SWR at

Another jig in this post…. /g/nanovna-users/message/20848