
USB power up problem and possible solutions (HW / SW)
#nanovnah4
#circuit
#usb
Hello Hugen, DiSlord and others, First: I know that this is a user and not developer forum. So please apologize for getting deeply into the code (for anyone not directly involoved). This is my first p
Hello Hugen, DiSlord and others, First: I know that this is a user and not developer forum. So please apologize for getting deeply into the code (for anyone not directly involoved). This is my first p

By
Rainer Schaack
· #24587
·


USB power up problem and possible solutions (HW / SW)
#nanovnah4
#circuit
#usb
Thank you ! I will check this and investigate further in the next days. Best regards, 73 Rainer, DK2ZR
Thank you ! I will check this and investigate further in the next days. Best regards, 73 Rainer, DK2ZR

By
Rainer Schaack
· #24568
·


USB power up problem and possible solutions (HW / SW)
#nanovnah4
#circuit
#usb
This not used in code. Need check: Si5351 start work  generate 8MHz clock for aic3204 codec aic3204 start work  send data over i2s bus to CPU
This not used in code. Need check: Si5351 start work  generate 8MHz clock for aic3204 codec aic3204 start work  send data over i2s bus to CPU

By
DiSlord
· #24563
·


USB power up problem and possible solutions (HW / SW)
#nanovnah4
#circuit
#usb
Hello, I’ve got two H4 (Nooelec, HW version 4.2). Both work fine and produce identical measurement results. But one of them has this behavior: If I connect USB (either PC or power supply) and switch o
Hello, I’ve got two H4 (Nooelec, HW version 4.2). Both work fine and produce identical measurement results. But one of them has this behavior: If I connect USB (either PC or power supply) and switch o

By
Rainer Schaack
· #24559
·


Devices under test and devices in a system
#measurement
#circuit
#newbie
Hi Steve, try using DiSlord to make up for what the Japanese stop. He may be receptive to this. Write down what you want to see that is not already in the firmware.
Hi Steve, try using DiSlord to make up for what the Japanese stop. He may be receptive to this. Write down what you want to see that is not already in the firmware.

By
Gyula Molnar
· #18308
·


Devices under test and devices in a system
#measurement
#circuit
#newbie
Dear John, Yes I have got the Japanese firmware on thee out of four of my V2 devices. It is excellent but he has announced he will not update it any more. This is a bit of a shame for V2 plus and V4 o
Dear John, Yes I have got the Japanese firmware on thee out of four of my V2 devices. It is excellent but he has announced he will not update it any more. This is a bit of a shame for V2 plus and V4 o

By
Stephen Laurence
· #18303
·


Devices under test and devices in a system
#measurement
#circuit
#newbie
Steve, I did a little more looking around: The NanoVNAV2 firmware from https://ojisankoubou.web.fc2.com/nanovna/nanovnav2.html has a very interesting feature: It allows the S parameters to be remapp
Steve, I did a little more looking around: The NanoVNAV2 firmware from https://ojisankoubou.web.fc2.com/nanovna/nanovnav2.html has a very interesting feature: It allows the S parameters to be remapp

By
John Gord
· #18301
·


Devices under test and devices in a system
#measurement
#circuit
#newbie
Steve, I seem to recall that my old HP 8712B allowed calibration with load resistances other than 50 ohms, and then scaled the display to match. It probably helped the accuracy a bit in the immediate
Steve, I seem to recall that my old HP 8712B allowed calibration with load resistances other than 50 ohms, and then scaled the display to match. It probably helped the accuracy a bit in the immediate

By
John Gord
· #18296
·


Devices under test and devices in a system
#measurement
#circuit
#newbie
I seem to recall, from the days when I tinkered with my radio kit, that things like crystal filters, ceramic filters etc had in and out impedances of hundreds of ohms or more. Also the designers attem
I seem to recall, from the days when I tinkered with my radio kit, that things like crystal filters, ceramic filters etc had in and out impedances of hundreds of ohms or more. Also the designers attem

By
Stephen Laurence
· #18295
·


Devices under test and devices in a system
#measurement
#circuit
#newbie
Steve, I kind of suggested that in my first post to Andrea. I have since checked the mixers used in the NanoVNA and they have an RF input impedance of 1.5kohm. That would suggest to me that if you had
Steve, I kind of suggested that in my first post to Andrea. I have since checked the mixers used in the NanoVNA and they have an RF input impedance of 1.5kohm. That would suggest to me that if you had

By
Evan Hand
· #18294
·


Devices under test and devices in a system
#measurement
#circuit
#newbie
Assuming a linear device, you can also renormalize the S parameters after measuring them in a 50 ohm environment (i.e., in postprocessing) to account for different source and/or load impedance. It's
Assuming a linear device, you can also renormalize the S parameters after measuring them in a 50 ohm environment (i.e., in postprocessing) to account for different source and/or load impedance. It's

By
Christian Zietz
· #18293
·


Devices under test and devices in a system
#measurement
#circuit
#newbie
This might be a “shootdowninflames” question, but..... Albeit that a vna has 50 ohm port impedances, the sol calibration (at least simplistically at low frequencies) is a 3 point calibration of a c
This might be a “shootdowninflames” question, but..... Albeit that a vna has 50 ohm port impedances, the sol calibration (at least simplistically at low frequencies) is a 3 point calibration of a c

By
Stephen Laurence
· #18292
·


Devices under test and devices in a system
#measurement
#circuit
#newbie
Hello Andrea; The vna is characterizing networks in a 50 ohm system. That is both the source and load termination are 50 ohms. If you have a filter network as you highlighted and it is not designed to
Hello Andrea; The vna is characterizing networks in a 50 ohm system. That is both the source and load termination are 50 ohms. If you have a filter network as you highlighted and it is not designed to

By
alan victor
· #18288
·


Devices under test and devices in a system
#measurement
#circuit
#newbie
I have tested many filters and antennas under various load conditions, from 10 Ohms, up through 150 Ohms. Inductance, capacitance, reactive loading, and Smith chart based indications for capacitive an
I have tested many filters and antennas under various load conditions, from 10 Ohms, up through 150 Ohms. Inductance, capacitance, reactive loading, and Smith chart based indications for capacitive an

By
ERNEST AECRADIO
· #18286
·


Devices under test and devices in a system
#measurement
#circuit
#newbie
Andrea, I'll start with the answer to your question on bandpass (or any filter) input and output impedance affecting the filter characteristics. The answer is yes, the filter needs to be designed to
Andrea, I'll start with the answer to your question on bandpass (or any filter) input and output impedance affecting the filter characteristics. The answer is yes, the filter needs to be designed to

By
Evan Hand
· #18283
·


Devices under test and devices in a system
#measurement
#circuit
#newbie
Some interesting reading in this group discussion.... https://groups.io/g/nanovnausers/topic/71668374#11504 This is about the MiniVNA but it has a filter discussion.... https://www.nonstopsystems.co
Some interesting reading in this group discussion.... https://groups.io/g/nanovnausers/topic/71668374#11504 This is about the MiniVNA but it has a filter discussion.... https://www.nonstopsystems.co

By
Roger Need
· #18282
·


Devices under test and devices in a system
#measurement
#circuit
#newbie
Hi! I recently got a NanoVNAF and I just had a quick reading of "A guide to NanoVNA", by Christoph and Maximilian Schwärzler, to have an overview of how to use a NanoVNA. There's still something impo
Hi! I recently got a NanoVNAF and I just had a quick reading of "A guide to NanoVNA", by Christoph and Maximilian Schwärzler, to have an overview of how to use a NanoVNA. There's still something impo

By
Andrea IK0RNT
· #18281
·


Resonate frequency of lossy networks... Simple One...
#circuit
Strictly speaking, there should be bounds on the R,C,L terms so they are less than one. Otherwise a second order system, a tuned network which must posses two memory components vanishes. Consider if R
Strictly speaking, there should be bounds on the R,C,L terms so they are less than one. Otherwise a second order system, a tuned network which must posses two memory components vanishes. Consider if R

By
alan victor
· #17430
·


Resonate frequency of lossy networks... Simple One...
#circuit
What will happen with resonant frequency when R>C/L and value under SQRT becomes negative? Will that create a black hole and the world as we know it will collapse in it? :) SPICE simulation shows phas
What will happen with resonant frequency when R>C/L and value under SQRT becomes negative? Will that create a black hole and the world as we know it will collapse in it? :) SPICE simulation shows phas

By
Miro, N9LR
· #17429
·


Resonate frequency of lossy networks... Simple One...
#circuit
Alan said: With very large resistance you effectively have current generator so you can plot voltage on the RLC circuit :) In my simulation, I used ideal voltage source and plotted the current  "shap
Alan said: With very large resistance you effectively have current generator so you can plot voltage on the RLC circuit :) In my simulation, I used ideal voltage source and plotted the current  "shap

By
Miro, N9LR
· #17428
·
