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Sincere apologies for something I must have done wrong. Please help me to understand how I should have explained the problem is most prominent at higher frequencies, much more then the 0.1 ohm

You say that because you never lived under a military dictatorship. These political comments (included mine) should be avoided, they are not good for the good health of the group. Ignacio, EB4APL --

Did you do a calculation over the total frequency range or only DC? The impedance mismatch was most prominent at higher frequencies due to SA602 input capacitance. Increasing R22 and R23 reduced this

ASSUMING the SA602 inputs are 1.5K each for a total of 3K my calculations come up with changing the 11 ohm 1% resistor with a 13.2 ohm 1% resistor from Digi-Key...?? 1 over 1/3000 + 1/91 + 1/115.2 =

I meant "there is not a good subsitute"

Thank you Helmut and Ignacio for the speedy replies. Helmut, I am running Windows 10 Home with all recent updates. I had thought about the permissions issue before posting, but was unable to find a

If you pay attention, the Smith Chart display on the nanoVNA lacks all units on its axes. This is because this display is intended to see where the impedances are. For measuring, instead of read it on

I am not sure if "reply " is attached to post or thread so.. To Alan Victor , OM - would it be possible / appropriate to discuss details of actual C code (OpenGL) implementation in private ? I am no

And like the current and maybe past few generations who grew up doing math on calculators, they can't even add and subtract without them. When the power goes poof, their tools are gone and they're

Have you the DFU mode driver installed? The normal series port emulator is? used by the Windows programs that communicates the nanoVNA with the PC, such as nanoVNA sarver, but for updating the

I agree...? I'm just saying my calculator says the original circuit is closer... If I was to change anything I'd swap the 11-ohm resistor with an 8.97-ohm 1% and I'd have a 49.998 impedance... ? 73

4.2.1 is better because the input impedance of the SA602 (1.5kOhm//3pF per input) has less impact compared to 4.2 -- NanoVNA Wiki: /g/nanovna-users/wiki/home NanoVNA Files:

These calculated values are correct if, and only if, the actual resistor values are exactly as marked which they will not be. 73 John M0JBA

That's not what my calculator says... 4.2 circuit:91 ohms in parallel with 51+11+51 take 1/91 + 1/113 = 1/x and that comes to 50.4068 ohms... When I do that to circuit 4.2.1 I come up with 50.64

It's just 1/x but flipped and shifted ;)

"Smith Chart : In this computer era, this extremely high-effort demanding, highly-inaccurate, old-time graphics tool became completely obsolete, because it is a totally useless one in every other

Oooh, si tacuisses ! You try to make believe to be way above it, but: Is that "innocent, unexperienced beginner" perhaps your own point of view? This computer era definitely did not come into

What operating system? WIN10 (and WIN7) protects some folders against modifications. Create a di

H4 F303 variant PCB artwork updated to 4.2.1 : Update the schematic diagram, the impedance of ch1 is closer to pure 50 ohms

For people actually designing RF equipment, the Smith Chart is a valuable tool. -- Carey Fisher careyfisher@...