anti-stati foam sheets for lining case
I'm considering using anti-static polyethylene foam sheets cut to fit in a case I have for my RF test gear. My thinking is that polyethylene is more stable than the other foams out there.
2 sources I have are Granger & McMaster-Carr Anyone have any thoughts?
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On 6/27/21 10:36 AM, Jim Cotton via groups.io wrote: I paid more for a good used HP 85032B N calibration kit for my 8702B than for the LibreVNA.
The LibreVNA has a spectacular price performance ratio and decent specifications to 3GHz, 3-6 GHz is a bonus and it certainly works well enough to be useful.
The software V1.1.2 with firmware 5 is usable if not full featured.
What tests would one choose to compare VNA'S?? Sweep a filter, impedance match a device, measure cable length, ...?
I suspect the majority of NanoVNA users use them at HF unless testing antennas...
Jimn8qoh Stuff you can do with some VNAs sweep a filter with many sections and narrow bandwidth (i.e. lots of envelope delay) sweep a crystal (sort of like above) testing an amplifier looking for a "small" mismatch in a long cable (i.e. put a tiny mismatch 10 meters from the end of a 30 meter cable with a fairly good load) with synthetic TDR measuring transformers and extracting parameters, particularly in a 4 port scenario (i.e. a transformer with two center tapped windings) measuring impedances that are a LONG way from 50 ohms (i.e. measuring small changes in reflection coefficient near 1) measuring mixers (lots of ways to do this with a two port analyzer) Some of this is more about calibration and stability than the raw SNR performance
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Re: Firmware version 1.0.39
Folks, to help with the issue DiSlord described below, I modified the DeFuse utility interface buttons to have better meanings.? Please download the zipped file from the forum's file section. It's under mods. Thread is here... /g/nanovna-users/topic/76480999#17028? On Sun., 27 Jun. 2021 at 1:46 p.m., DiSlord<dislordlive@...> wrote: Most ofen mistake - user upload fw from device to CPU (use upload action) and rewrite downloaded firmware. After correct use Upgrade button - user just reload old firmware stored in downloaded file. Reload firmware from internet, and use correct upgrade action in DFUSe
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I paid more for a good used HP 85032B N calibration kit for my 8702B than for the LibreVNA.
The LibreVNA has a spectacular price performance ratio and decent specifications to 3GHz, 3-6 GHz is a bonus and it certainly works well enough to be useful.
The software V1.1.2 with firmware 5 is usable if not full featured.??
What tests would one choose to compare VNA'S?? Sweep a filter, impedance match a device, measure cable length, ...?
I suspect the majority of NanoVNA users use them at HF unless testing antennas...
Jimn8qoh
On Sun, Jun 27, 2021 at 10:15 AM, Donald S Brant Jr<dsbrantjr@...> wrote: John:? I ordered and received a LibreVNA from R&L Electronics, was pleased at the price ($429 vs $599 at Amazon), ordering and delivery, and quality of the unit.? The software is a work in progress but the version I am using (1.1.2) seems stable and reasonably intuitive.
I believe that the weakness of the unit is the provided calibration standards and their definitions; I am using the values on the attached document and they seem to work well up to 4GHz, but quickly fall apart above that. I am considering purchasing calibration standards from SDR-Kits which I understand are made by Rosenberger.? I also plan to measure the provided standards on a commercial VNA and use the S1P/S2P files as standards definitions; the LibreVNA software will accept measured data for the cal standards in lieu of L/C/Z/delay coefficients.
I also noticed that the LibreVNA runs hot, with the internal temperatures reporting as ~53-56¡ãC; I have obtained a fan-cooled heatsink and some thermal interface material and plan to install then and see the results.? However I do not see any temperature-related drift or other issues, coming from a semiconductor reliability background I just prefer to have things run cooler.
I am currently using the LibreVNA to evaluate components for a project at work (L-band beacon receiver with VHF IF) and the measurements I am getting compare favorably with the measurements from a Keysight Field Fox analyzer.
I suspect that when I get adequate calibration standards and definitions I will be quite pleased with the performance of the unit; it is already proving useful in my work.
73, Don N2VGU
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Re: Firmware version 1.0.39
Most ofen mistake - user upload fw from device to CPU (use upload action) and rewrite downloaded firmware. After correct use Upgrade button - user just reload old firmware stored in downloaded file.
Reload firmware from internet, and use correct upgrade action in DFUSe
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Re: Firmware version 1.0.39
This is how it should look when DfuSe is started. Put the NanoVNA-H4 in DFU mode beforehand.
When the NanoVNA-H4 is put into DFU mode, the PC emits a beep (USB port ready).
Is that how it looks with you?
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last iteration of Nano VNA PPT de k3eui
I have had my Nano VNA now for about 10 months and I think I have now exhausted everything I can do with it.
A year ago I could not tell you what the letters "VNA" even mean (I did know what nano means).
But ideas pop up and I have to pull the Nano VNA out again and try something new.
I've done so much that I now have way too many slides for a one our talk, or even a two hour talk.
But I have divided this PPT into two parts:
Part I The Basics - I try not to get too deep into the weeds
Part II Advanced - much more in depth stuff, and stuff on antenna impedance and matching
I've given "live" Zoom talks now to over a dozen clubs, throughout the USA and two in Europe.
This has been a learning experience for me in many ways.
So I want to thank those kind enough to offer suggestions (and point out errors).
You know who you are.
So perhaps this is not a complete story yet, but I hope this contains some slides for useful discussions.
If you do spot an error please let me know (off list at k3euibarry@...)
Please use this resource any way you feel appropriate.
I hope I did not violate any image copyright laws as I put these slides together.
73
de k3eui Barry
West Chester PA
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Re: Firmware version 1.0.39
You have updated FW 0.5.0 (Hugen) to 1.0.39 (DiSlord). What a software have You used for FW flashing?
Vladimir
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Re: Firmware version 1.0.39
Have You tried
1. DfuSe
2. NanoVNA-APP 1.1.206
for FW flashing?
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John: I ordered and received a LibreVNA from R&L Electronics, was pleased at the price ($429 vs $599 at Amazon), ordering and delivery, and quality of the unit. The software is a work in progress but the version I am using (1.1.2) seems stable and reasonably intuitive.
I believe that the weakness of the unit is the provided calibration standards and their definitions; I am using the values on the attached document and they seem to work well up to 4GHz, but quickly fall apart above that. I am considering purchasing calibration standards from SDR-Kits which I understand are made by Rosenberger. I also plan to measure the provided standards on a commercial VNA and use the S1P/S2P files as standards definitions; the LibreVNA software will accept measured data for the cal standards in lieu of L/C/Z/delay coefficients.
I also noticed that the LibreVNA runs hot, with the internal temperatures reporting as ~53-56¡ãC; I have obtained a fan-cooled heatsink and some thermal interface material and plan to install then and see the results. However I do not see any temperature-related drift or other issues, coming from a semiconductor reliability background I just prefer to have things run cooler.
I am currently using the LibreVNA to evaluate components for a project at work (L-band beacon receiver with VHF IF) and the measurements I am getting compare favorably with the measurements from a Keysight Field Fox analyzer.
I suspect that when I get adequate calibration standards and definitions I will be quite pleased with the performance of the unit; it is already proving useful in my work.
73, Don N2VGU
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Re: Firmware version 1.0.39
I press the function wheel + turn on and no "Available DFU Devices" appear in the software. I can import the new firmware but not upload to device. It is a Nano VNA-H4 HW Version 42 S/N H4 20050921.
Thanks for your response.
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Re: VNA measures other than antenna SWR de k3eui
Good Catch.
I did the S21 (through the RLC series circuit center conductor of coax) but I forgot - the S21 is already loaded at 50 ohm internal.
so the first time I did the trial, I had R=100 ohm and I missed the Bull's Eye on the Smith Chart.
So I just bypassed the 50ohm R (with some internal inductance) and got these graphs.
But good catch in both cases.
Wire-wound resistors will also have inductance.
Now I will have to go back and measure the L of my "resistor" 10W Radio Shack at 3-5 MHz.
It did show me that all of the graphs indicated the same concept:'
At resonance of series RLC circuit (R=50 ohm)
The SWR is lowest at 3.65 MHz, the resonant frequency
The Smith Chart passed through the Bull's Eye only at 3.65 MHz
The R and X graphs still confuse me a bit, but X is changing much faster than R around resonant frequency 3.65 MHz
The PHASE graph continues to make me smile: yes, at resonance, the phase changes sign
The RETURN LOSS is just superb and very deep (except that I am still plotting this as negative dB, and yes, I know RL is positive)
This is fun (especially during a rain storm)
de k3eui Barru
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One thing to realize about the LibreVNA is that it has no screen.? Your PC or laptop is the display and processor.? The performance I get with a USB 3.0, 16 Gig RAM, four core 3.9 GHz processor machine may be much different than what someone else gets with a "minimum to run Windows" laptop with a 2 GHz, two core atom and 4 Gig of RAM....
Jimn8qoh
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The LibreVNA is available from Zeenko store on AliExpress.? The price is $399 + shipping which was $39 to the US.? They have roughly 30 left out of the 100 initial run.? I see other stores now starting to offer the LibreVNA at $830+850 plus shipping.... I'm not sure if this is scalping or the planned pricing...
I am helping some graduate students who are designing and testing ion thrusters at the university plasma lab.??
The LibreVNA is not a $50K instrument, however it compares favorably with one of the Rigol or Siglent spectrum analyzers that have "network analyzer" features added to it and it is two port.??
The case is CNC cut metal and it is not twitchy when you wave your hands around it.? The cables and standards that came with it are of higher quality than came with the NanoVNA SAA2 I have had contact with.? They are still not the quality of a HP/Agilent calibration kit.
The SDR-Kits units use metrology grade connectors and have higher quality calibration kits available.? They have a European audience and a high technical content in their user group.? One of the members published a how-to book for the unit which is excellent.
Jim
On Sat, Jun 26, 2021 at 4:17 PM, n2msqrp<mstangelo@...> wrote: If you want to do full two port forward and reverse measurements the VNWA-3SE and LibreVNA supports this feature. The others do not. SDRKits has excellent support and the LibreVNA looks impressive.
Mike N2MS
toggle quoted message
Show quoted text
On 06/26/2021 1:17 PM John AE5X < ae5x@... > wrote:
Thanks for the comments, Jim - and for the potential offer. Yes, they nano
2 docs specifically mention that it cannot be used for measuring crystal
parameters. I had been looking at a LibreVNA - I like the upper freq limit
and other specs and would like to have shown it to my co-workers (radar
techs and engineers) but whoever moderates the io.group evidently didn't
see the relevance of a question regarding the ordering process and
documentation availability so the plan to purchase evaporated instantly.
I haven't ruled out an SDR-Kits VNA - but I do need to know what I'd be
gaining for the extra $$$. That is the purpose of the upcoming comparison,
all of which will be with passive devices.
I have an FA-VA5 from them and am well aware of the high quality of these
products, typical of what we've come to expect from German engineering
(which also applies to my .22 Beeman R9)!
Thanks again and 73,
--
John AE5X
The SDR-Kits software is more refined. Their calibration kits are of
higher mechanical and electrical quality.
I use it for things like sorting crystals for ladder crystal filters and
LF/HF tasks.
I find it more convenient than the HP 3577A (5 Hz - 200 MHz) in many
cases.
The HP 8702B (a 3 GHz 8753C with the word optical in the description and a
slightly different ROM set) compares favorably with the 0-3 GHz
specifications of the LibreVNA. The HP wins in the software capabilities
and interface.
I am currently using the LibreVNA from 2-6 GHz along with HP 8595E/8596E
and a DS Systems tracking generator. The LibreVNA
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Re: Nano-F - Did I make a Mistake?
I purchased a NanoVNA-F a few weeks or months after first buying a 2.8 inch NanoVNA. I wanted the -F for its MUCH better screen - I could not read the screen of the first, smaller unit while outdoors testing and adjusting my antenna. I had to connect it to the 'in-the-shack' end of the antenna cable and go inside and to the far end of the house to see if I adjusted the antenna correctly. Then back out for the next re-adjustment.
Operation of the -F and -H is nearly the same, and it's easy to switch between them. I do still use my 2.8 inch -H while I'm in the ham shack checking an antenna that's standing out in the yard or strung up in the nearby trees.
I have not seen the screen of the -H4 and can't really comment on its usefulness, but I DO consider the -F to be definitely the best choice. If I lost mine and had to replace it, I would certainly get another -F. If you use your Nano outdoors, you'll be glad you got the -F.
--
Doug, K8RFT
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Re: FM5324B and FM5401 - NanoVNA-H4 Battery Charger and 5 Volt Converter Circuit
On 6/26/21 4:02 PM, Kent AA6P wrote: I didn't initially notice Larry's comment that pulling the USB cable extinguishes the Battery LED. My NanoVNA-H4 does not operate that way so maybe the difference is the FM5324B chip.
The Battery LED in my unit only flashes below 3.6 volts so the indicator is useful in that one regard. Otherwise, the Battery LED is steady on whenever the unit is turned on.
The operation of this LED is very different with the NanoVNA-H4 and NanoVNA-H.
Here is a surprise. I have an AC Outlet Power Meter and decided to check the AC wattage when charging the NanoVNA-H4. I have three different AC to USB phone charger adapters. The wattage readings were 7.8 watts, 10.7 watts, and 11.5 watts using the three different AC adapters. All readings were higher than expected. The battery charge current must be quite high.
Measurements on my NanoVNA-H were all in the range of 1.5 watts to 1.7 watts. That seems much more reasonable.
73, Kent
AA6P Or the chargers have wildly varying efficiency or (more likely) they have weird power factor/current waveform that "fools" the power meter. In addition to the trusty Kill-A-Watt for AC, I have a couple USB power meters that are quite handy.? And, if there's still something weird looking, there's the trusty 0.1 ohm resistor and the scope to look at the current waveform.
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Re: FM5324B and FM5401 - NanoVNA-H4 Battery Charger and 5 Volt Converter Circuit
I didn't initially notice Larry's comment that pulling the USB cable extinguishes the Battery LED. My NanoVNA-H4 does not operate that way so maybe the difference is the FM5324B chip.
The Battery LED in my unit only flashes below 3.6 volts so the indicator is useful in that one regard. Otherwise, the Battery LED is steady on whenever the unit is turned on.
The operation of this LED is very different with the NanoVNA-H4 and NanoVNA-H.
Here is a surprise. I have an AC Outlet Power Meter and decided to check the AC wattage when charging the NanoVNA-H4. I have three different AC to USB phone charger adapters. The wattage readings were 7.8 watts, 10.7 watts, and 11.5 watts using the three different AC adapters. All readings were higher than expected. The battery charge current must be quite high.
Measurements on my NanoVNA-H were all in the range of 1.5 watts to 1.7 watts. That seems much more reasonable.
73, Kent
AA6P
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If you want to do full two port forward and reverse measurements the VNWA-3SE and LibreVNA supports this feature. The others do not. SDRKits has excellent support and the LibreVNA looks impressive.
Mike N2MS
toggle quoted message
Show quoted text
On 06/26/2021 1:17 PM John AE5X < ae5x@... > wrote:
Thanks for the comments, Jim - and for the potential offer. Yes, they nano
2 docs specifically mention that it cannot be used for measuring crystal
parameters. I had been looking at a LibreVNA - I like the upper freq limit
and other specs and would like to have shown it to my co-workers (radar
techs and engineers) but whoever moderates the io.group evidently didn't
see the relevance of a question regarding the ordering process and
documentation availability so the plan to purchase evaporated instantly.
I haven't ruled out an SDR-Kits VNA - but I do need to know what I'd be
gaining for the extra $$$. That is the purpose of the upcoming comparison,
all of which will be with passive devices.
I have an FA-VA5 from them and am well aware of the high quality of these
products, typical of what we've come to expect from German engineering
(which also applies to my .22 Beeman R9)!
Thanks again and 73,
--
John AE5X
The SDR-Kits software is more refined. Their calibration kits are of
higher mechanical and electrical quality.
I use it for things like sorting crystals for ladder crystal filters and
LF/HF tasks.
I find it more convenient than the HP 3577A (5 Hz - 200 MHz) in many
cases.
The HP 8702B (a 3 GHz 8753C with the word optical in the description and a
slightly different ROM set) compares favorably with the 0-3 GHz
specifications of the LibreVNA. The HP wins in the software capabilities
and interface.
I am currently using the LibreVNA from 2-6 GHz along with HP 8595E/8596E
and a DS Systems tracking generator. The LibreVNA
|
Thanks for the comments, Jim - and for the potential offer. Yes, they nano 2 docs specifically mention that it cannot be used for measuring crystal parameters. I had been looking at a LibreVNA - I like the upper freq limit and other specs and would like to have shown it to my co-workers (radar techs and engineers) but whoever moderates the io.group evidently didn't see the relevance of a question regarding the ordering process and documentation availability so the plan to purchase evaporated instantly.
I haven't ruled out an SDR-Kits VNA - but I do need to know what I'd be gaining for the extra $$$. That is the purpose of the upcoming comparison, all of which will be with passive devices.
I have an FA-VA5 from them and am well aware of the high quality of these products, typical of what we've come to expect from German engineering (which also applies to my .22 Beeman R9)!
Thanks again and 73,
--
John AE5X
The SDR-Kits software is more refined. Their calibration kits are of higher mechanical and electrical quality.
I use it for things like sorting crystals for ladder crystal filters and LF/HF tasks.
I find it more convenient than the HP 3577A (5 Hz - 200 MHz) in many cases.
The HP 8702B (a 3 GHz 8753C with the word optical in the description and a slightly different ROM set) compares favorably with the 0-3 GHz specifications of the LibreVNA. The HP wins in the software capabilities and interface.
I am currently using the LibreVNA from 2-6 GHz along with HP 8595E/8596E and a DS Systems tracking generator. The LibreVNA came with better quality cabling and calibration kit than the NanoVNA variants I have.
John, contact me if you are still looking for a SDR-Kits VNWA 3 to borrow.
Jimn8qoh
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Vladimir Lebedev
Barry K3EUI
Donald S Brant Jr
OwO