Re: NanoVNA-H4 What are the exact steps to a
On Sun, Mar 15, 2020 at 08:00 PM, hwalker wrote:
On Sat, Mar 14, 2020 at 09:38 PM, <hugen@...> wrote:
The NanoVNA-H4 uses DAC output dimming, so the brightness can be adjusted
using DAC commands. Dac_value = 800 is the minimum brightness, dac_value =
3300 is the maximum brightness, you can enter any number between 800-3300 for
brightness adjustment.
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Note: 1800 is the default, out-of-box, NanoVNA-H4 mid-range brightness
setting. I always wondered about the purpose of the "dac" console command,
although on the 2.8" NanoVNA-H's it's use is evidently reserved for other
(future?) purposes.
- Herb
The NanoVNA originally designed by edy555 allows the use of DAC to adjust VCTCXO, but when I made NanoVNA-H, I thought that adjusting VCTCXO was too much trouble for most users, so I used TCXO. For most VNA users, 2ppm TCXO can fully meet the test requirements. For geeks who may need more accurate frequency calibration, I think they can be easily calibrated by software. Therefore, the DAC on the 2.8-inch NanoVNA-H has no practical use.
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Re: NanoVNA-H4 What are the exact steps to a
On Sat, Mar 14, 2020 at 09:38 PM, <hugen@...> wrote:
The NanoVNA-H4 uses DAC output dimming, so the brightness can be adjusted using DAC commands. Dac_value = 800 is the minimum brightness, dac_value = 3300 is the maximum brightness, you can enter any number between 800-3300 for brightness adjustment.
================================================================
Note: 1800 is the default, out-of-box, NanoVNA-H4 mid-range brightness setting. I always wondered about the purpose of the "dac" console command, although on the 2.8" NanoVNA-H's it's use is evidently reserved for other (future?) purposes.
- Herb
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Re: NanoVNA-H4 What are the exact steps to a
Thank you for the command information, Hugen.
I have a minor H4 firmware enhancement request: is it possible to use the jog switch to change also brightness when in the brightness config GUI menu?
I'm sure many users would find that method to be preferable.?
Cheers,
Larry
On Sun, 15 Mar 2020 at 12:38 AM, hugen@...<hugen@...> wrote: hwalker11 is right. The NanoVNA-H4 uses DAC output dimming, so the brightness can be adjusted using DAC commands. Dac_value = 800 is the minimum brightness, dac_value = 3300 is the maximum brightness, you can enter any number between 800-3300 for brightness adjustment.
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Re: NanoVNA-H4 What are the exact steps to a
hwalker11 is right. The NanoVNA-H4 uses DAC output dimming, so the brightness can be adjusted using DAC commands. Dac_value = 800 is the minimum brightness, dac_value = 3300 is the maximum brightness, you can enter any number between 800-3300 for brightness adjustment.
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Re: NanoVNA-H4 What are the exact steps to a
On Sat, Mar 14, 2020 at 07:10 PM, Larry Rothman wrote:
Maybe Hugen can let everyone know if there is a Console command to adjust the brightness on the H4?
===============================================================
NanoVNA-H4
# Shell Commands: help exit info threads version reset freq offset time dac saveconfig clearconfig
# data frequencies port stat gain power sample scan sweep test touchcal touchtest pause resume
# cal save recall trace marker edelay capture vbat transform threshold vbat_offset
No H4 shell commands for the display other than touchcal. Brightness is manually adjusted from the "BRIGHTNESS" sub-menu under the "CONFIG" tab. No documentation has been provided, but my experimentation shows 100 step increments from 800 to 3300 give visual brightness changes (i.e. 800, 900, 1000 ....). 800 is the lowest brightness and 3300 is the highest.
- Herb
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On Sat, Mar 14, 2020 at 05:36 PM, Kurt Poulsen wrote:
Hi Roger
Using the S21 methods requires that both the source (CH0) and load (CH1)
impedance are pure 50 ohm, so you get also errors this way. Have you tried to
read the Rp instead of Rs in NanoVNA-saver. That makes a big difference to the
R values as it is often forgotten the standard impedance displayed are R+jX
and then the R value is frequency dependent due to the X value present. Often
the use of port extension can cure the problem if the DUT is mounted to an
adaptor introducing a shunt C.
Kind regards
Kurt
Kurt, Thanks for your comments. Yes I am familiar with the using Rp instead of Rs in NanoVNA saver. I agree that the CH0 and CH1 impedance needs to be close to 50 ohms for accurate results using the S21 method. I have found using attenuator pad(s) and "calibrating them out" helps but of course that reduces the impedance range that can be measured.. I am only interested below 55 MHz. so that alleviates the 50 ohm impedance issue as well. I hope to post some results showing complex impedance measurements using my S21 test jig and different parts before too long. Roger
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Re: NanoVNA-H4 What are the exact steps to a
Maybe Hugen can let everyone know if there is a Console command to adjust the brightness on the H4?
I've been attempting to keep Cho45's Original userguide up to date and have added quite a bit of content but since I don't own an H4, any extra/new commands have not been explored by me so I will probably do one more update and pass the torch on to someone with the newer device.?
... Larry
On Sat, 14 Mar 2020 at 9:38 PM, Robert Klaus<robert.w7xlr@...> wrote: Thank you, found that out later after I did the jumper update. I'm just scared to mess with the display setting anymore I don't want to end up stuck with a dark screen. It may be as bright as it gets already, just don't know. If not I will have to fabricate some type of screen hood for outside use...
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Re: NanoVNA-H4 What are the exact steps to adjus
Thank you, found that out later after I did the jumper update. I'm just scared to mess with the display setting anymore I don't want to end up stuck with a dark screen. It may be as bright as it gets already, just don't know. If not I will have to fabricate some type of screen hood for outside use...
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Re: NanoVNA-H4 What are the exact steps to adjus
Robert,
You no longer have to open the case to jumper the booth pins.?
To put the unit into dfu mode, turn it off, press in and hold the jog switch and then turn on the unit and release the switch.?
If you own an older Nanovna, you can mod it to do the same with just one jumper wire and a resistor.?
If someone can specify the steps for the brightness setting, I can add it to my userguide.?
Cheers
Larry
On Sat, 14 Mar 2020 at 7:22 PM, Robert Klaus<robert.w7xlr@...> wrote: What are the exact steps to adjust the display brightness? Mine comes up with a keypad and 1 800 I think it was. I tried something and it went dim and I managed to get it back where it was. I would like to make it brighter if possible. BTW after opening mine to jump the contacts for the firmware upgrade it, it then had the case causing the menu issue to start. I just loosened the case screw a bit and solved the problem...
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Hi Roger Using the S21 methods requires that both the source (CH0) and load (CH1) impedance are pure 50 ohm, so you get also errors this way. Have you tried to read the Rp instead of Rs in NanoVNA-saver. That makes a big difference to the R values as it is often forgotten the standard impedance displayed are R+jX and then the R value is frequency dependent due to the X value present. Often the use of port extension can cure the problem if the DUT is mounted to an adaptor introducing a shunt C. Kind regards Kurt -----Oprindelig meddelelse----- Fra: [email protected] < [email protected]> P? vegne af Roger Need via Groups.Io Sendt: 15. marts 2020 00:59 Til: [email protected]Emne: Re: [nanovna-users] Checking 1:49 UnUn with nanovna #applications On Sat, Mar 14, 2020 at 04:36 PM, WB2UAQ wrote: I also measured the feed point impedance of a 67 ft wire at 7 MHz using the
Nanovna and found it to be 3600 to 3900 ohms shunted by about 8 pF. This Z
is about 1250-j1820...way out of the range of the Nanovna (S11) Yes the S11 bridge method starts to get quite inaccurate after the impedance gets higher than a few hundred ohms. Fortunately the NanoVNA can do S21 measurements and we can determine complex impedance at several thousand ohms using the "Series Method" shown below. The equations are not that complicated and I was hoping Rune could add them to NanoVNA Saver. Presently I do them in a spreadsheet after an import of a S21 Touchstone file. Roger
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On Sat, Mar 14, 2020 at 04:36 PM, WB2UAQ wrote: I also measured the feed point impedance of a 67 ft wire at 7 MHz using the
Nanovna and found it to be 3600 to 3900 ohms shunted by about 8 pF. This Z
is about 1250-j1820...way out of the range of the Nanovna (S11) Yes the S11 bridge method starts to get quite inaccurate after the impedance gets higher than a few hundred ohms. Fortunately the NanoVNA can do S21 measurements and we can determine complex impedance at several thousand ohms using the "Series Method" shown below. The equations are not that complicated and I was hoping Rune could add them to NanoVNA Saver. Presently I do them in a spreadsheet after an import of a S21 Touchstone file. Roger
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I have tested the 1:49 transformer loss and found it to be 1 to 1.5 dB depending on the band. I checked this loss several ways with good agreement using the Nanovna.
I also measured the feed point impedance of a 67 ft wire at 7 MHz using the Nanovna and found it to be 3600 to 3900 ohms shunted by about 8 pF. This Z is about 1250-j1820...way out of the range of the Nanovna (S11) so I used a tuned circuit method with the Nanovna and went to the old GR-821-A (Twin T Impedance Measuring Circuit). Good agreement with both techniques.
It happens that the equivalent source Z of the transformer is a resistance in series with an inductive reactance so there is a rough conjugate match with the EFHW wire.
This wire tested against a ground stake from 12 inches above the ground to a tree placing the wire at about a 45 deg angle to the ground. I tested this same wire at 3 locations. At home, 30 miles south of home and 80 miles to the SE of home (Home is about 10 miles from Rochester, NY). I can't be sure if the "ground" conditions are similar or different:)
I did all of this stuff because I asked questions on several on-line discussion group and didn't get very good scientific answers from anyone.
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NanoVNA-H4 What are the exact steps to adjust the display brightness?
What are the exact steps to adjust the display brightness? Mine comes up with a keypad and 1 800 I think it was. I tried something and it went dim and I managed to get it back where it was. I would like to make it brighter if possible. BTW after opening mine to jump the contacts for the firmware upgrade it, it then had the case causing the menu issue to start. I just loosened the case screw a bit and solved the problem...
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To test for insertion loss (S21) you need two identical back to back.
You may want to observe phase with frequency as well.
In those cases you ahv eto allow for two devices so the insertion
loss is 1/2 that measured.
S11 can also be measured that way with 50 ohm termination.
Or with 2450 (2500 nominal) ohm resistor.
Power handeling is realted to mismatch and that means you
need a variable reactive load and a resistive load.
Why?
If the wire is perfectly tuned for low SWR and no reactance (s11) seen then
it will be efficient. As the frequency diverges from that point high or low the
antenna wire (the load) appears as capacitive (lower frequency)
or inductive (higher frequency). In the end the transformer becomes
less efficient for non resonant cases depending on how far off.
IN those cases the ability to withstand power is diminished.
For power handling make the core as large as possible within limits.
The biggest limits is residual lead inductance and ability to achieve
tight enough coupling.
Allison
----------------
No direct email, it goes to bit bucket due address harvesting in groups.IO
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Thanks Herb!
On the larger screen being a lot slower, it should only be slower based on the number of pixels compared between models.
I had to do a lot of rewriting of library lcd routines from Adafruit and others.? My screen updates were unacceptable using
the standard library routines.? I timed how long it took to write an entire line of text 32 pixels high.? then, starting to rewrite
the stuff one part at a time.? I ended up with code that was 17x faster.
I am hoping that was the "old" days 3 years ago, where the library routines were functional, but not optimized!
73
Glen K4KV
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On 3/14/2020 14:40, hwalker wrote: Dislord, the talented Russian coder, who collaborated with edy555 on his recent 0.7.0 firmware release has uploaded a beta 0.8 firmware with the following Google directly translated Russian comments:
" After edy555 added my font fixes, optimized space in RAM, I was offered many fixes regarding the speed, functionality and optimization of resources
In this beta firmware I added the color command, accelerated the speed of display and scanning, eliminated artifacts when displaying, accelerated marker and included display of the marker data when driving, eliminated problems with third-party software and more (as was the limit on the size of the site) add something else, 80% of the code was rewritten, as a result released about 18kB pso (Flash?) and 3kB oz (RAM?), which will give the opportunity to further build up the functionality) I post the current beta version at .
What is interesting, since the library for the generator has been rewritten, and the scanning has been significantly accelerated (but the stability must be improved), I would like to check whether everything has become good or bad (it is desirable to make a comparison with firmware from edy555 v0.7 and the last from hugen) the firmware is suitable for the original NanoVNA and NanoVNA-H, but not suitable for F or H4 (there is another processor and screen).
Maybe (if I buy the H4 version) I'll adapt the changes for it as well.
PS despite the faster-acting processors in the F and H4 versions, they don't work faster (the larger screen is a big load on the data processor) and the original NanoVNA bottleneck had a lack of resources (which was eliminated), as most of the time (about 60% of the time) the processor is idle waiting for the results of measurements, which has been much improved. " End of Quote
I loaded the beta firmware version on my NanoVNA-H without any problems using DFU-Demo. Screen update is faster and none of the display artifacts observed in previous firmware versions was noted during limited testing. This is a beta firmware version release so any bugs should be reported to DisLord's GitHub page. If you are not adventurous I would suggest waiting for edy555's official 0.8.0 release. Reiterating DisLord, please note that this beta firmware release is not for the NanoVNA-H4 or NanoVNA-F because they use different processors and screen sizes than the NanoVNA-H.
- Herb
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Dislord, the talented Russian coder, who collaborated with edy555 on his recent 0.7.0 firmware release has uploaded a beta 0.8 firmware with the following Google directly translated Russian comments:
" After edy555 added my font fixes, optimized space in RAM, I was offered many fixes regarding the speed, functionality and optimization of resources
In this beta firmware I added the color command, accelerated the speed of display and scanning, eliminated artifacts when displaying, accelerated marker and included display of the marker data when driving, eliminated problems with third-party software and more (as was the limit on the size of the site) add something else, 80% of the code was rewritten, as a result released about 18kB pso (Flash?) and 3kB oz (RAM?), which will give the opportunity to further build up the functionality) I post the current beta version at .
What is interesting, since the library for the generator has been rewritten, and the scanning has been significantly accelerated (but the stability must be improved), I would like to check whether everything has become good or bad (it is desirable to make a comparison with firmware from edy555 v0.7 and the last from hugen) the firmware is suitable for the original NanoVNA and NanoVNA-H, but not suitable for F or H4 (there is another processor and screen).
Maybe (if I buy the H4 version) I'll adapt the changes for it as well.
PS despite the faster-acting processors in the F and H4 versions, they don't work faster (the larger screen is a big load on the data processor) and the original NanoVNA bottleneck had a lack of resources (which was eliminated), as most of the time (about 60% of the time) the processor is idle waiting for the results of measurements, which has been much improved. " End of Quote
I loaded the beta firmware version on my NanoVNA-H without any problems using DFU-Demo. Screen update is faster and none of the display artifacts observed in previous firmware versions was noted during limited testing. This is a beta firmware version release so any bugs should be reported to DisLord's GitHub page. If you are not adventurous I would suggest waiting for edy555's official 0.8.0 release. Reiterating DisLord, please note that this beta firmware release is not for the NanoVNA-H4 or NanoVNA-F because they use different processors and screen sizes than the NanoVNA-H.
- Herb
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On Sat, Mar 14, 2020 at 10:12 AM, Jim Potter wrote:
...mine was the smaller screen version, but the AURSINC version was complete with battery and shielding. I find it convenient to use it with my laptop, but I haven't taken it into the field.
=====================================================
If you are only using it connected to a laptop and don't have trouble navigating the 2.8" screen, then upgrading to the 4" version is not a rush. Eventually, because its faster processor and larger flash memory will allow the firmware developer's to add some cool must have feature (i.e. more measurement points), you'll want to upgrade.
If I was purchasing today, for only an additional $10, I would buy the NanoVNA-H4 over the NanoVNA-H. My ham club has the NanoVNA-F, NanoVNA-H ver 3.4, NanoVNA-H4 and we have just ordered a SAA-2 (NanoVNA-V2). Total cost for all was less than we paid for our first MFJ antenna analyzer.
- Herb
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Praba Karan,
Depends what you are trying to check and over what frequency range? Are you just looking to measure VSWR vs frequency or other things maximum power handling capability, efficiency (meaning PowerOut/PowerIn) etc.
Roger
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Thanks, mine was the smaller screen version, but the AURSINC version was complete with battery and shielding. I find it convenient to use it with my laptop, but I haven't taken it into the field.
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On Sat, Mar 14, 2020 at 09:30 AM, Mark Schoonover wrote:
Another approach is to put a 2.5K resistor across the output.
=========================================================
That was pretty much the same reply to his question on Facebook by Robert Fontana ....
"A 49:1 transformer should map 2450¦¸ (49x50¦¸) into 50¦¸. If you place a (noninductive) 2400¦¸ resistor across the terminals and use the NanoVNA to measure VSWR, you should see a reasonably flat and low VSWR across the frequency of operation ...
Note, this only measures its low signal response, and does not take into account core saturation at higher power levels. It will, however, tell you over what frequency range the core is good for."
I guess he is looking for a different approach.
- Herb
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Roger Need
Robert Klaus W7XLR
Kurt Poulsen
