Thanks for the link - worked perfectly! I just put the following together as I managed to get it all up and running on a Fire Tablet, rather than a standard Android tablet.
Using NanoVNA with Amazon Fire Tablet 7 (9th generation) running OS 7.3.1.5
You need to be able to install Google Playstore. There are plenty of websites telling you how to do it, such as:
Load Chrome browser onto tablet.
Instructions here () but ensure you put this in Chrome chrome://flags/#enable-experimental-web-platform-features and Enable the flag for experimental procedures.
Then type this into Chrome and bookmark it:
Use an OTG connector (this is the one I have: ) and the long USB-to-C cable to connect to the NanoVNA. Swoitch on the NanoVNA and you should be able to connect and see the screen update on the tablet.
The other thing you can do from your Fire Tablet is update the NanoVNA firmware. I used the STMDfuUsb software from
Download the latest firmware onto your tablet and unzip it (B1 Free Archiver works well, free Amazon App). Run the STMDfuUsb software and connect to NanoVNA via your OTG lead. Put the NanoVNA into DFU mode through the menu (or via hardware) and it should connect. Select ¡®Load file to flash¡¯ and find your ¡®ch.hex¡¯ file, select it and flash it. The programmer then tells you how many times you can use it again. It starts at 25, so that means I can flash another 24 versions of firmware which seems pretty good to me.
I¡¯m by no means technically competent with linux/DFU, etc, and so I¡¯m pretty pleased I managed to do the above and it works.
Hope this helps others link their NanoVNAs with these cheap little Amazon tablets.
Regards,
Mike
MM0GUX
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Re: New open source VNA released - excellent performance claimed
No, that is an amplifier!!!
You really see it when you have the input power (S11) reduced to -30 dB or so.
High performance VHF/UHF GaAs FET preamps are usually pretty close toedge of their stability factors.???? And you do see this!
We will get into how the stability of the preamp is affected by the antenna andthe use of isolators another day.
Kent WA5VJB
PS? And we will save Parametric Amplifiers for another time! hihi????? (Para Amps have one port/connector?? That one connector is
???????? both the RF input and the RF Output!)
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Show quoted text
On Tuesday, September 29, 2020, 7:05:34 PM CDT, Jim Allyn - N7JA <jim@...> wrote: On Tue, Sep 29, 2020 at 12:14 PM, KENT BRITAIN wrote: You would be amazed how many LNA's have a POSITIVE Return Loss.i.e. more comes
back than goes in! That's not an amplifier, that's an oscillator.
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Re: New open source VNA released - excellent performance claimed
On Tue, Sep 29, 2020 at 12:14 PM, KENT BRITAIN wrote: You would be amazed how many LNA's have a POSITIVE Return Loss.i.e. more comes
back than goes in! That's not an amplifier, that's an oscillator.
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Re: Measuring CMC and S21 readings
You are correct, forgot that the equivalence does not hold when the real part is negative. Corrected and cleaned up version is attached. On Tue, 29 Sep 2020 at 23:36, Piero Tognolatti <piero.tognolatti@...> wrote: Dragan, in the column "G" it is not correct to use ATAN function! The
correct expression for cell "G3" is =DEGREES(ATAN2(D3;E3))) The same
for the following rows.
Piero, I0KPT
Il 29/09/2020 23:03, Dragan Milivojevic ha scritto:
Try the attached spreadsheet
On Tue, 29 Sep 2020 at 22:38, Federico - ik3umt <ik3umt@...> wrote:
That's what I'm trying to do with nanovna....
Which S21 values should i insert in Steve's spreadsheet ?
Which format conversion is needed ?
Federico
ik3umt
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Re: Wireless remote control of nanoVNA-H
Steve,
You can add the serial port if you can solder two wirewrap wires to the uP pins. Refer to the most recent H schematic for the pins. They are 3v signals so you'll need a level shifter/interface on the lines.?
I've installed a 32khz xtal and tf slot on my older Nanovna and will be bringing the serial lines out as well to a small header. Have a look at the photo I posted a couple of days ago of my board mods.?
... Larry
On Tue, 29 Sep 2020 at 6:55 PM, Stephen Hughey<shughey@...> wrote: Larry,
Thank you again for your quick response.? Mine is not in a plastic case and is apparently a much older unit without the serial port on the board edge.? I will look on the Wiki and find the references that you suggest.
Steve
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Re: Wireless remote control of nanoVNA-H
Larry,
Thank you again for your quick response. Mine is not in a plastic case and is apparently a much older unit without the serial port on the board edge. I will look on the Wiki and find the references that you suggest.
Steve
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Re: Connect Antenna Trap to NanoVNA
A good way to check trap resonance, if possible, is to open the lead of the capacitor or the inductor and connect the VNA and a 50 Ohm resistor across the open. At resonance the L and C cancel and you read 50 Ohms. This avoids using long leads from the VNA to the ends of the trap.
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Re: Wireless remote control of nanoVNA-H
Stephen,
If you have an official H with the plastic housing and hardware version 3.4.2 you need to open the housing and look at the edge of the PCB. The serial port will be at the edge beside the boot0 pins.?
If you don't have the version of PCB with the serial port, you will have to bring out some jumpers directly by soldering some wires to the processor.?
There are schematic and PCs references on the forum Wiki
?
On Tue, 29 Sep 2020 at 5:44 PM, Stephen Hughey<shughey@...> wrote: This is absolutely super!
I have downloaded and installed this firmware version in my vna-H successfully.? Looking at my board, however, I do not see any serial connections.? Can someone give advice or direction.? Do I need a newer board, and if so how do I order one knowing I have an updated board with a serial port or can I hardwire in a serial port to any older board without the connections brought out to the board edge?
Thanks in advance, with special gratitude to the small handful of developers that have provided many hours of enjoyment and interest to me.
Steve, AK4R
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Re: Wireless remote control of nanoVNA-H
This is absolutely super!
I have downloaded and installed this firmware version in my vna-H successfully. Looking at my board, however, I do not see any serial connections. Can someone give advice or direction. Do I need a newer board, and if so how do I order one knowing I have an updated board with a serial port or can I hardwire in a serial port to any older board without the connections brought out to the board edge?
Thanks in advance, with special gratitude to the small handful of developers that have provided many hours of enjoyment and interest to me.
Steve, AK4R
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Re: Measuring CMC and S21 readings
Dragan, in the column "G" it is not correct to use ATAN function!??? The correct expression for cell "G3" is =DEGREES(ATAN2(D3;E3)))? The same for the following rows.
Piero, I0KPT
toggle quoted message
Show quoted text
Il 29/09/2020 23:03, Dragan Milivojevic ha scritto: Try the attached spreadsheet
On Tue, 29 Sep 2020 at 22:38, Federico - ik3umt <ik3umt@...> wrote:
That's what I'm trying to do with nanovna....
Which S21 values should i insert in Steve's spreadsheet ?
Which format conversion is needed ?
Federico
ik3umt
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Re: need a startup guide that describes the behavior of the LEDs on the side
One is the charge led that flashes while being charged and is steady when fully charged. The other flashes in step with the sweep when on
Gary
W9TD
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Re: Measuring CMC and S21 readings
Try the attached spreadsheet
toggle quoted message
Show quoted text
On Tue, 29 Sep 2020 at 22:38, Federico - ik3umt <ik3umt@...> wrote: That's what I'm trying to do with nanovna....
Which S21 values should i insert in Steve's spreadsheet ?
Which format conversion is needed ?
Federico
ik3umt
|
Re: Measuring CMC and S21 readings
Federico, I am running nanovna-saver-v0.2.0, that export .s2p file using the "RI" format (one column for the real part, another column for the imaginary part).?? I see that Steve's? spreadsheet uses as input the "MA" format (Magnitude in dB and Angle in degs). Delay column is not used by Steve's formulas.
I don't know if more recent versions of nanovna-saver allow to save .s2p file in MA format.? In any case you can modify the spreadsheet in order to use input data in "RI" format.
Best 73
Piero, I0KPT
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Show quoted text
Il 29/09/2020 22:38, Federico - ik3umt ha scritto: That's what I'm trying to do with nanovna....
Which S21 values should i insert in Steve's spreadsheet ?
Which format conversion is needed ?
Federico
ik3umt
|
need a startup guide that describes the behavior of the LEDs on the side
I've scanned some of the materials and cannot find any descriptions of the
states of the LEDs. Any clues?
Thanks,
Roger
N1EYZ
Roger Tobin
Roger.tobin@... <mailto:Roger.tobin@...>
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Re: Measuring CMC and S21 readings
That's what I'm trying to do with nanovna....
Which S21 values should i insert in Steve's spreadsheet ?
Which format conversion is needed ?
Federico
ik3umt
|
Re: New open source VNA released - excellent performance claimed
You would be amazed how many LNA's have a POSITIVE Return Loss.i.e. more comes back than goes in!??? Kent WA5VJB
toggle quoted message
Show quoted text
On Tuesday, September 29, 2020, 11:59:27 AM CDT, Jim Lux <jimlux@...> wrote: On 9/29/20 9:27 AM, Jerry Gaffke via groups.io wrote: I would think attenuators and booster amps may as well be in the external cables.
Not terribly familiar with all this, perhaps there are special tricks involved to measure
something like s12 on an amp? Oohh. that's everyone's first guess.. but think about it.. if you want to measure the S11 of a LNA, you can't put 50dB of attenuation in front of it.? You put 50 dB of attenuation in the stimulus line, then the bridge, then 50dB of amplifier in the receiver line.? Then calibrate as per usual.? If your receiver has good dynamic range, you don't need as much amplifier. Adding them to a $300 VNA board adds complication and sources of trouble.
Modular is good when it comes to seldom needed features. True - maybe a different version of the board, that just leaves out the resistive bridge.? And some extra SMA connectors
The ability to use a different bridge would be interesting.
Perhaps lay out the board such that? one could insert vertical SMA's
and stir some surface mount parts to accommodate this?
Yet another product variant for Hugen to sell at some time in the future.
But I suspect most nanovna users have never felt the need for an external bridge.
Requiring an external bridge for all work with the VNA is perhaps a bridge too far
towards modularity.
Typically, the way it's done is to have two connectors with a removable jumper between them. I would venture that for most VNAs that have this, the jumpers have never been removed except when doing factory cal/re-cal.? Or when someone sets the VNA down on a non-smooth surface and breaks the jumper.
Jerry, KE7ER
On Tue, Sep 29, 2020 at 08:47 AM, Jim Lux wrote:
yes, it's going towards the fieldfox type of capability, not the "bench VNA" -
The latter would typically bring out the source and receiver inputs with a
loop, so you could use different bridge or insert attenuation to make it
easier to test amplifiers.
This design has a 30dB sep attenuator, but still, if you're testing a LNA with
a maximum input of -70 dBm (because it's designed to receive signals at -150
dBm) this probably isn't your box of choice. Assuming he's putting +10 into
the attenuator, the output power will be -20 dBm or around there. That's
enough to saturate a lot of LNAs.
Likewise, if you were testing a 10W PA, you might want a booster amplifier in
the drive on port 1, and an attenuator in port 2.
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Re: Connect Antenna Trap to NanoVNA
Also, after thinking about this a little bit, the resonant frequency of the
trap likely stays pretty much put.
However, the trap would significantly affect the antenna resonant frequencies for which the trap is not resonant.
Which is to say, you'd best listen to somebody else!
Jerry, KE7ER
toggle quoted message
Show quoted text
On Tue, Sep 29, 2020 at 10:44 AM, Jerry Gaffke wrote: Correction to an obvious error:
Parallel tuned is a high impedance at resonance.
Jerry, KE7ER
Hide quoted text ( #quoted-173058290 )
On Tue, Sep 29, 2020 at 08:36 AM, Jerry Gaffke wrote:
I would probably test a parallel tuned trap as a single port, with the far
end
of the trap grounded.
Should see the impedance head towards zero at the resonant frequency.
But could also be done as a 2 port measurement, loss approaching zero at
the
resonant frequency.
You will find that the resonant frequency will change when the trap is
part of
an antenna.
So do a single port test of the completed antenna, that's the real test.
Could be displayed as impedance, SWR, Smith Chart, whatever you are
comfortable with.
Look at each band individually, sweeping all of HF may not give enough
resolution to see resonances.
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Herb,
Thank you so much for re-printing this here - saved my bacon!
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Re: Connect Antenna Trap to NanoVNA
Correction to an obvious error:
Parallel tuned is a high impedance at resonance.
Jerry, KE7ER
toggle quoted message
Show quoted text
On Tue, Sep 29, 2020 at 08:36 AM, Jerry Gaffke wrote:
I would probably test a parallel tuned trap as a single port, with the far end
of the trap grounded.
Should see the impedance head towards zero at the resonant frequency.
But could also be done as a 2 port measurement, loss approaching zero at the
resonant frequency.
You will find that the resonant frequency will change when the trap is part of
an antenna.
So do a single port test of the completed antenna, that's the real test.
Could be displayed as impedance, SWR, Smith Chart, whatever you are
comfortable with.
Look at each band individually, sweeping all of HF may not give enough
resolution to see resonances.
|
Re: New open source VNA released - excellent performance claimed
On 9/29/20 9:27 AM, Jerry Gaffke via groups.io wrote: I would think attenuators and booster amps may as well be in the external cables.
Not terribly familiar with all this, perhaps there are special tricks involved to measure
something like s12 on an amp? Oohh. that's everyone's first guess.. but think about it.. if you want to measure the S11 of a LNA, you can't put 50dB of attenuation in front of it. You put 50 dB of attenuation in the stimulus line, then the bridge, then 50dB of amplifier in the receiver line. Then calibrate as per usual. If your receiver has good dynamic range, you don't need as much amplifier. Adding them to a $300 VNA board adds complication and sources of trouble.
Modular is good when it comes to seldom needed features. True - maybe a different version of the board, that just leaves out the resistive bridge. And some extra SMA connectors The ability to use a different bridge would be interesting.
Perhaps lay out the board such that one could insert vertical SMA's
and stir some surface mount parts to accommodate this?
Yet another product variant for Hugen to sell at some time in the future.
But I suspect most nanovna users have never felt the need for an external bridge.
Requiring an external bridge for all work with the VNA is perhaps a bridge too far
towards modularity. Typically, the way it's done is to have two connectors with a removable jumper between them. I would venture that for most VNAs that have this, the jumpers have never been removed except when doing factory cal/re-cal. Or when someone sets the VNA down on a non-smooth surface and breaks the jumper. Jerry, KE7ER
On Tue, Sep 29, 2020 at 08:47 AM, Jim Lux wrote:
yes, it's going towards the fieldfox type of capability, not the "bench VNA" -
The latter would typically bring out the source and receiver inputs with a
loop, so you could use different bridge or insert attenuation to make it
easier to test amplifiers.
This design has a 30dB sep attenuator, but still, if you're testing a LNA with
a maximum input of -70 dBm (because it's designed to receive signals at -150
dBm) this probably isn't your box of choice. Assuming he's putting +10 into
the attenuator, the output power will be -20 dBm or around there. That's
enough to saturate a lot of LNAs.
Likewise, if you were testing a 10W PA, you might want a booster amplifier in
the drive on port 1, and an attenuator in port 2.
|
Jim Allyn - N7JA
Stephen Hughey
Ken
Gary W9TD