Re: Protective Case for H4
I looked at the case, I had similar thoughts, but I would have holes for the coax cables to connect to the NanoVna and also an extention to mount
whatever test board you are using, in my case the SDRKits test pcb.
Would seem pretty easy to drill holes for the cables to come out, then mount your protective case on another longer board to have a place to mount the test fixture.
Hope that adds some ideas.
Mikek
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Re: Protective Case for H4
That is cool. 1. Do you have pics to share to show? 2. Are you going to make any to sell, for those of us without 3D printers? (Yes, there are still some of us out there)... [image: photo] *Bob Willey* K3RLW (410) 251-8960 | K3RLW@... 5161 Ocean Gateway, Trappe Maryland 21673-2023 USA <> <> <> <> On Thu, Jul 16, 2020 at 9:24 AM Darrell Carothers <rescuemedic1@...> wrote: Just FYI, I designed a protective case for the H4. It is a bit oversized
to allow additional SMA connectors to be left on to prevent abuse to the
connectors attached directly to the circuit board.
The files are on Thingiverse. I 3D printed mine in PLA but any material
should work. There is a bit of room between the connectors at the top to
allow a small piece of rubber to be placed if you desire a tighter fit.
Look for NanoVNA H4 case or under my designs using Medic433.
Hope you find it useful.
Darrell Carothers
Sent from my over-rated IPhone 7 Plus. Any Mis-spellings or grammar
errors are due to my IPhone auto correct feature.
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Re: Protective Case for H4
Looks to be this
Dave-KB1PVH
Sent from my Galaxy S9
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On Thu, Jul 16, 2020, 4:46 PM Rick Commo <rick.commo@...> wrote: What¡¯s the thingiverse number?
Thanks,
-rick, K7LOG
On Jul 16, 2020, at 06:23, Darrell Carothers <rescuemedic1@...>
wrote:
Just FYI, I designed a protective case for the H4. It is a bit oversized
to allow additional SMA connectors to be left on to prevent abuse to the
connectors attached directly to the circuit board.
The files are on Thingiverse. I 3D printed mine in PLA but any material
should work. There is a bit of room between the connectors at the top to
allow a small piece of rubber to be placed if you desire a tighter fit.
Look for NanoVNA H4 case or under my designs using Medic433.
Hope you find it useful.
Darrell Carothers
Sent from my over-rated IPhone 7 Plus. Any Mis-spellings or grammar
errors are due to my IPhone auto correct feature.
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Re: Protective Case for H4
What¡¯s the thingiverse number?
Thanks,
-rick, K7LOG
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On Jul 16, 2020, at 06:23, Darrell Carothers <rescuemedic1@...> wrote:
Just FYI, I designed a protective case for the H4. It is a bit oversized to allow additional SMA connectors to be left on to prevent abuse to the connectors attached directly to the circuit board.
The files are on Thingiverse. I 3D printed mine in PLA but any material should work. There is a bit of room between the connectors at the top to allow a small piece of rubber to be placed if you desire a tighter fit. Look for NanoVNA H4 case or under my designs using Medic433.
Hope you find it useful.
Darrell Carothers
Sent from my over-rated IPhone 7 Plus. Any Mis-spellings or grammar errors are due to my IPhone auto correct feature.
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Re: Protective Case for H4
I just don¡¯t have exact measurements to verify the fitting for the other models.
Sent from my over-rated IPhone 7 Plus. Any Mis-spellings or grammar errors are due to my IPhone auto correct feature.
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On Jul 16, 2020, at 10:33, K4YQ - Steve <K4YQ@...> wrote:
?Thanks Darrell I'll take a look. I've been putting off designing one for myself so this may save me some time...
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On 16.07.20 17:48, John Nicholas wrote: Git Hub shows 0.0.3.6-rc2 is the latest version of NanoVNA Saver
Should I be staying with the 0.0.3 version? or moving to the 0.3.3.6
version?
KEoZUW John On my own PC and with my nanovna firmware 0.8.0 or dislord's current one and with my nanovna v2 0.3.6-rc2 works more reliable as v0.3.4 and a lot better then v0.3.0 but some quirks seems to exist, but I'm unable to reproduce them. 73 Holger, DG5DBH
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Git Hub shows 0.0.3.6-rc2 is the latest version of NanoVNA Saver
Should I be staying with the 0.0.3 version? or moving to the 0.3.3.6 version?
KEoZUW John
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On Jul 15, 2020, at 1:44 PM, Holger M¨¹ller <dg5dbh@...> wrote:
It was a bug releases between v0.3.0 and v0.3.2
fixed in v0.3.3
73
Holger, DG5DBH
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Re: Identifying ferrite materials with S11 measurements
On Thu, Jul 16, 2020 at 07:50 AM, alan victor wrote:
This measurement technique was addressed many months ago in a prior thread.
I'll note that unwanted shunt-capacitance can result in errors (that increase in frequency) when measuring large impedances using "configuration 3" in the Copper Mountain doc. This same shunt capacitance is why you cannot use S11 to measure large impedances. Admittedly, the shunt-Cap errors in "configuration 3" measurements are likely to be small. Never the less, the "Y21" method of impedance measurement (see link in first post of this thread) should remove (or significantly reduce) this source of measurement error, should it be a concern. - Jeff, k6jca
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Re: Protective Case for H4
Thanks Darrell I'll take a look. I've been putting off designing one for myself so this may save me some time...
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Re: VBAT resistor voltage divider, polynomial fitting, VBAT sampling
FYI - In the current source code the internal on-chip vbat divider is always enabled. There is an option where the divider is switched on/off before/after the actual vbat measurement via ADC1_17 (based on #define F303_ADC_VREF_ALWAYS_ON).
Hopefully the internal divider is disabled when the MCU is off :)
The required minimal sampling time for the vbat measurement is 2.2us (see the reference manual).
Current ADC setting is
#define ADC_VBAT_SMP_TIME ADC_SMPR_SMP_601P5
that is 614 clocks - around 8us @ 72MHz.
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Re: Identifying ferrite materials with S11 measurements
This measurement technique was addressed many months ago in a prior thread.
You can now go to the Copper Mountain web site and read this specific paper that was published in RF and Microwaves earlier in the year.
Alan
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Re: VBAT resistor voltage divider, polynomial fitting, VBAT sampling
The Vbat, at least what I see in the sources for H4, is being sampled such the Vbat voltage divided by 2 (internal on-chip divider, most probably disconnected when not in use) is converted via the ADC channel 17. There are no external dividers needed.
The rather unusually high noise in the vbat data readings I presented in my other post could be caused by something missing in the H4 code, ie. a small delay should be inserted after activating the divider - before reading the vbat, or something like that..
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Just FYI, I designed a protective case for the H4. It is a bit oversized to allow additional SMA connectors to be left on to prevent abuse to the connectors attached directly to the circuit board.
The files are on Thingiverse. I 3D printed mine in PLA but any material should work. There is a bit of room between the connectors at the top to allow a small piece of rubber to be placed if you desire a tighter fit. Look for NanoVNA H4 case or under my designs using Medic433.
Hope you find it useful.
Darrell Carothers
Sent from my over-rated IPhone 7 Plus. Any Mis-spellings or grammar errors are due to my IPhone auto correct feature.
|
Re: Bettering the resistors' network on the RX input?
Dear Clifford,
I've studied Dunsmore's publication (thanks for the link!), as I can understand it is more about the way to enhance the U7's input (I'm referring to the 3.4.2) network, namely, the R9~R21.
But as I can see it, there is another cause for worries - the frequency-dependence of SA612's input impedance.
Along with that bridge we also must compensate for SA612's input capacitance. I think it should be possible by connecting an inductor (several nH) in series with the R20 and R21 in CH0 and R25 in CH1.
I do not yet know if this bridge should be used in CH1 too. Most probably - yes, it should be.
Please comment.
Warm regards,
Anton
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Re: VBAT resistor voltage divider, polynomial fitting, VBAT sampling
There have been several threads in the various nanovna forums about the value of applying engineering to these devices.
For the record:
You statements are incorrect, except, perhaps where you imply that you didn't check the manual.
You didn't read the schematics I sent.
You didn't read the accompanying text.
You don't understand how simple the math is.
...and more...
You summarily dismissed something without understanding what you were dismissing. And then got 2 up votes for that. This certainly sets the standard for how we are to interact with developers.
All the NanoVNAs in this class still reflect much creativity and energy, and they are still a very good value for the cost. But they could be so far ahead of where they are now if the developers were more open to sharing ideas and learning from the mistakes of others. I decided to reply here because anyone else reading this thread should be aware the the original post contained information that was completely ignored in the response and the up votes.
--
72/73 de Rich NE1EE
On the banks of the Piscataqua
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Re: Identifying ferrite materials with S11 measurements
Nice write-up of the measurement problems. Rings a few bells.
Now with the nano, I measered several resistive loads (47 to 10k) using S11 en S21 in the HF range a few weeks ago. For high impedance values S11 measurements were not even close, as expected.
Here's the measurement of a 10k 5%? 1/4W normal resistor (no smd) from the junkbox using S21.
Reworked calculated series impedance into parallel resistor and capacitor values is what you see in the graph.
I was amazed. My relatively old nano H3.2 + nanoSAVER 0.2.1 do pretty well.
73,
Arie PA3A
Op 16-7-2020 om 01:45 schreef WB2UAQ:
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Hi Jeff,
Here's the paper: Showed up below as Challengesandsolutionsforimpedance
When I did the complex algebra it was a good refresher.
73, Pete
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Re: Identifying ferrite materials with S11 measurements
Excellent! Thanks very much, Pete.
73,
Jeff, k6jca
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Re: Identifying ferrite materials with S11 measurements
Hi Jeff,
Here's the paper: Showed up below as Challengesandsolutionsforimpedance
When I did the complex algebra it was a good refresher.
73, Pete
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On 15.07.20 13:14, MarkZ wrote: Hi,
I tried this (once) with the latest code and it seemed to work fine.
I also looked through the code and didn't see any reason for what
you're describing. There have been a lot of changes to the export
code recently.
Have you tried with the latest executable?
-Mark It was a bug releases between v0.3.0 and v0.3.2 fixed in v0.3.3 73 Holger, DG5DBH
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Bob Willey K3RLW
David Webb
Darrell Carothers
John Nicholas
Rich NE1EE
Arie Kleingeld PA3A
