Re: nano vna h black screen
shoot in the dark .. a nano vna H ??
dg9bfc sigi
Am 02.03.2025 um 16:21 schrieb Tim Dawson:
By
Siegfried Jackstien
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#39598
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Re: nano vna h black screen
Telling us what model Nano-VNA you have would be a good starting point.
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
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Tim Dawson
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#39597
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nano vna h black screen
problem started when i attempted to upgrade, screen went black, foolishly did not save the old version.. now i can read the vna with stm32, it even appears to write the new firmware but still a black
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VA4BG
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#39596
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Re: High impedance measurement with VNA?
Jim, thank you a lot for the detailed information. I will be able to do some surgery on one of the NanoVna gen111.taobao.com firmware, which I updated to 0.3.0m. I will have to check the schematics
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pattymorr@...
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#39595
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Re: High impedance measurement with VNA?
The NanoVNA doesn't have a separate Source and receiver ports, so you can't do the external amplifier, coupler approach in the Rackley paper.
Is there a reason you need high power for the test?
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Jim Lux
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#39594
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Re: High impedance measurement with VNA?
The NanoVNA doesn't have a separate Source and receiver ports, so you can't do the external amplifier, coupler approach in the Rackley paper.
Is there a reason you need high power for the test?
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Jim Lux
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#39593
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Re: High impedance measurement with VNA?
From amfone :https://amfone.net/Amforum/index.php?topic=37502.0;wap2
John K5PRO:
Before the days of plastic antenna analyzers, you either used a GR bridge or a slotted line (for VHF), or just knew
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pattymorr@...
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#39592
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Re: High impedance measurement with VNA?
Thanks Jim, now I understand better.
So, I will build a LC tuning circuit and I will measure afterwards to adjust it.
--
73 s Christian F8GHE
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Christian BARTHOD F8GHE
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#39591
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Re: S-Parameter Plotter
I've added impedance measurements to the S-parameter plotter. It now includes the one-port reflection method and the two-port series-through, shunt-through, and Y21 methods. Y21 cancels stray port
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Brian Beezley
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#39590
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Re: Am I in the right track ?
Roger,
Thanks. I thought I had replied yesterday but apparently not. Well, let me shop some 0603 resistors and ferrites and I'll come back once I get something decent.
Also, my board is scrap.
1-
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Nico
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#39588
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Re: High impedance measurement with VNA?
Some of those techniques are more about measuring a high impedance component, so they wouldn’t work.
You’re making an S11 measurement - it’s just challenging because for end fed antennas,
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Jim Lux
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#39587
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Re: High impedance measurement with VNA?
Jim thanks very much for your advise.
During this afternoon I found these urls and now I don't know what is the best way to measure my end-feed antenna : Your or one of these :
-
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Christian BARTHOD F8GHE
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#39586
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Re: My NanoVNA-H4 is bricked. Is there a manual internal switch to reset?
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
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M0CNL
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#39585
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Re: My NanoVNA-H4 is bricked. Is there a manual internal switch to reset?
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
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Roger Need
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#39584
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Re: Am I in the right track ?
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
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Roger Need
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#39583
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My NanoVNA-H4 is bricked. Is there a manual internal switch to reset?
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
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Len Ward <W5MW@...>
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#39582
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Re: Am I in the right track ?
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
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W0LEV
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#39581
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Re: High impedance measurement with VNA?
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? |
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Jim Lux
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#39580
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High impedance measurement with VNA?
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
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Christian BARTHOD F8GHE
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#39579
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S-Parameter Plotter
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
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Brian Beezley
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#39578
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