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Frank - do a search though the forum and you'll find all kinds of useful info that others have already supplied...

Have a look at my posts & photos - I stuck an old Motorola 800mAH cellphone batt on mine - no probs.

...Larry

Does anyone know how big a battery in mAh (charging wise) the unit can handle?
Frank

Is anyone interested in an extended back cover for the NanoVNA? I designed and printed a sample it has a 6mm deep "pocket" that is 71mm X 40mm. Should be big enough to double sided tape a bigger battery in it

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Frank
ka2fwc@...

I just ordered 1 from Banggood preorder, I hope this is the correct one to make sure Huegen gets paid for his work

Several discussions with my ham colleague Gary, N3GO and wrestling in a quite area,
I believe I have ONE approach that works well and is consistent with proper results.
The main items to note: Only TWO traces are present during the cal, LESS CONFUSION!
The frequency selection I chose, start and stop, is just an example.
The use of the RESET soft touch is crucial. And I should update message #83. I believe that RESET
eliminates the BOGUS firmware process that takes you to the DONE soft key premature!!
===================================================================
Calibration for 4 track nanoVNA (VNA)

Some notes: If you can have on hand another 50 ohm termination
and another female-female SMA adapter, it is helpful.

Supplied and used are the TWO- matched cables, the LOADS and one SMA adapter.
Each of the NUMBERED items below represent your PRESS (SOFT KEY TOUCH).

Turn on the VNA and note register 0 is ON.
CONNECT THE EQUAL LENGTH MALE-to-MALE COAX CABLES TO CH0 AND CH1.

1. DISPLAY
2. TRACE 0
3. SINGLE
4. TRACE 1

Now we are displaying S11 and S22 ONLY both as LOGMAG.

5. STIMULUS
6. START 100 KHZ
7. STOP 500 MHZ
8. BACK
9. CAL
10.RESET
11.CALIBRATE

Note! None of the softkeys on the right side touch screen are highlighted.
Place an OPEN on end of CH0 cable and this will be followed by a SHORT.

12.OPEN
13.SHORT

Place a 50 ohm LOAD(s) on the end of cables for CH0 and CH1.

14.LOAD
15.ISOLN

Connect the 2-cables together using the female-female SMA adapter.

16.THRU
17.DONE

Finally save to a desired register.

That's it. Check and be sure that the open, short and 50 ohm are on the proper
side of the chart. Note, the cables are CONNECTED to CH0 and CH1 and the calibration is to the end of the cables. The reference plane for insertion loss measure magnitude is in place of the adapter. However, the
phase is subject to error and that needs addressed in another message.

Also, with a thru cable connection between CH0 and CH1, the
loss measure, S21 should be nearly 0 dB.

Alan W4AMV

You know, of course, that the signal out is a square wave.
According to the schematic, the Si5351 feeds the output directly through the resistor bridge..

I believe that's exactly how they have extended the range of this instrument to 900MHz: by using the harmonics.
otherwise Si5351 is only rated up to 200-300MHz. This is the same principle used in EU1KY antenna analyzer

I was interested in the performance of the output signal. So at first I measured the output power:
10 MHz -12,13 dBm
50 MHz -12,57 dBm
100 MHz -13,21 dBm
200 MHz -14,85 dBm
300 MHz -7,92 dBm
400 MHz -8,07 dBm
500 MHz -8,25 dBm
600 MHz -8,90 dBm
700 MHz -8,57 dBm
800 MHz -8,76 dBm

Frequency Offset:
Set to 100 MHz measurement was 99,999 908 MHz which is an offset of 92 Hz. Excellent !!!

Output Spectrum:
Spectrum is fine up to 270 MHz with harmonics at least 20dB down
However above this frequency there is a strong subharmonic or spurious 12dB higher than the wanted signal. See picture enclosed. I have no idea how this may influence our measurements. In the pictures some sent to the group I can not see negative results.
This probably explains why output power is higer at 300MHz and above.

Ernst

This is a very interesting group. I am not a radio expert or hobbyist. I am using vector network analysers to make biological and chemical sensors from piezoelectric resonators ranging from 200MHz surface acoustic wave devices, to 4GHz bulk acoustic wave devices. My devices of course are equivalent LCR circuit units, so I use the Butterworth van Dyke model to try to make sense of my resonators outputs.



Thank you for showing me where the software was to run the nanoVNA. I also have a Pocket VNA and a HP8753D. I am very pleased with the functionality of the nanoVNA.



Sent from Mail<> for Windows 10



________________________________
From: [email protected] <[email protected]> on behalf of alan victor via Groups.Io <avictor73@...>
Sent: Tuesday, July 9, 2019 7:59:47 PM
To: [email protected]
Subject: [nanovna-users] Higher frequency dynamic range... UHF Helical

This is the highest filter I had from the junk box without exceeding the limits of the instrument. The next filter up was centered at 902 MHz. So trying to get a sense of measurement DR would be a stretch.

This is a 6 pole UHF helical filter centered at ~ 490 MHz after re-tuning.
This noise floor of the response is HEAVILY dependent on the dressing of the cables the vendor supplies.
The cal routine I used included ISOLN as required, however, both CH0 and CH1 ports are
terminated with 50 ohm. So at UHF, if you average the noise in your head, about 70-75 dB DR.

Despite getting consistent cals with the 2 track VNA (the white gecko) or antenna analyzer, I am not certain the convoluted cal routine of the 4 track or black VNA is IDENTICAL. I would think it would be, however, some peculiar cal results do occur. Incidentally, the black unit has a firmware boot message, GEN11.TAOBAO.COM. Is this the latest firmware? I am going to guess maybe not.

This is the highest filter I had from the junk box without exceeding the limits of the instrument. The next filter up was centered at 902 MHz. So trying to get a sense of measurement DR would be a stretch.

This is a 6 pole UHF helical filter centered at ~ 490 MHz after re-tuning.
This noise floor of the response is HEAVILY dependent on the dressing of the cables the vendor supplies.
The cal routine I used included ISOLN as required, however, both CH0 and CH1 ports are
terminated with 50 ohm. So at UHF, if you average the noise in your head, about 70-75 dB DR.

Despite getting consistent cals with the 2 track VNA (the white gecko) or antenna analyzer, I am not certain the convoluted cal routine of the 4 track or black VNA is IDENTICAL. I would think it would be, however, some peculiar cal results do occur. Incidentally, the black unit has a firmware boot message, GEN11.TAOBAO.COM. Is this the latest firmware? I am going to guess maybe not.

Thanks Larry, Yes... understood.

My acid test so to speak was the 1 dB pad shorted which resulted in a Gamma of 0.86. I found the white unit quite good and published the polar response in a prior message. So at this point and with focus mostly on HF antenna work, not sure I am ready to modify. However, your efforts are instrumental in pushing this hardware to the next level. 73' Alan

________________________________
From: [email protected] <[email protected]> on behalf of Larry Rothman <ac293@...>
Sent: Tuesday, July 9, 2019 4:33 PM
To: [email protected]
Subject: Re: [nanovna-users] Adding Shields and an SD-card slot

Hi Alan,
I've got the antenna analyser firmware installed and I'm not really using the device for S parametric testing.
My 'lower noise' comment referred to a quick & dirty test (I'm at work so can't do too much right now) that produced what appears to be a more-even response above VHF frequencies after I re-calibrated the unit (50K to 900M).
Prior to this, my device provided poor SWR readings at the higher freqs.
I still need to play with it to see how things have changed but it looks better than what I was previously seeing.

When I first for the Gecko unit, I assumed the back plate had 1 side of copper - but it's just bare FR4, hence the need for shields.
Now to start playing with the source code to see if there's enough uP flash storage left to add additional SD r/w routines ;-)

Cheers,
Larry

Hi Alan,
I've got the antenna analyser firmware installed and I'm not really using the device for S parametric testing.
My 'lower noise' comment referred to a quick & dirty test (I'm at work so can't do too much right now) that produced what appears to be a more-even response above VHF frequencies after I re-calibrated the unit (50K to 900M).
Prior to this, my device provided poor SWR readings at the higher freqs.
I still need to play with it to see how things have changed but it looks better than what I was previously seeing.

When I first for the Gecko unit, I assumed the back plate had 1 side of copper - but it's just bare FR4, hence the need for shields.
Now to start playing with the source code to see if there's enough uP flash storage left to add additional SD r/w routines ;-)

Cheers,
Larry

Hi Larry, thanks for the inputs.

Can you elaborate on the statement: big difference in noise levels.

The second photo shows a closeup of the installed shields - big difference in noise levels!

If you are doing just one port measurement, then I assume lower noise implies less uncertainty in the readout of the S11 parameter. Less bouncing around in it's value. Is that correct?

Or if it is S21 and you are using a 4 track machine and measuring S21 then this big difference in noise would result in a lower noise floor in the THRU measurement and greater dynamic range. Below ~ 200 MHz I see about 70 dB or better and at frequencies approaching 900 MHz, there is a fairly linear degradation in the black nanoVNA. However, the largest limit in DR appears to be the cables themselves. I'll elaborate on that in another message. Thanks, Alan

________________________________
From: [email protected] <[email protected]> on behalf of Larry Rothman <ac293@...>
Sent: Tuesday, July 9, 2019 2:55 PM
To: [email protected]
Subject: [nanovna-users] Adding Shields and an SD-card slot

[Edited Message Follows]

I have been hacking my Gecko unit to add shields and I also decided to add an SD card slot I removed from an old Blackberry cellphone.
As I mentioned in a previous post, old 2-way radios and cellphones have a treasure trove of re-usable parts.
The first photo shows a pile of shields from several old Motorola HT1250 portables. Cellphone shields are similar.
I got the TF card slot from an old Blackberry.
Use a heat gun to remove them as well as switches.
TIP: Heat the opposite side of the PCB when removing parts to prevent heat damage.

The second photo shows a closeup of the installed shields - big difference in noise levels!

The third and fourth photos show the TF card slot where I had to scrape some ground plane solder mask for securing it.
In the upper left corner, you can see the push button I installed on the BOOT solder pads.
I know the firmware doesn't support the SD card - yet - but that is what hacking is all about!
Now, I'm waiting to receive the Black (Original design) version with the USB-C connector .
BTW, that old Motorola cellphone battery lasts well over 4 hours.

Hi Larry,
You can also add solder points to the SMA sockets. On the black NanoVNA they are welded on both sides, but only one PCB side is soldered on the white NanoVNA.
David, F4HTQ.

I have been hacking my Gecko unit to add shields and I also decided to add an SD card slot I removed from an old Blackberry cellphone.
As I mentioned in a previous post, old 2-way radios and cellphones have a treasure trove of re-usable parts.
The first photo shows a pile of shields from several old Motorola HT1250 portables. Cellphone shields are similar.
I got the TF card slot from an old Blackberry.
Use a heat gun to remove them as well as switches.
TIP: Heat the opposite side of the PCB when removing parts to prevent heat damage.

The second photo shows a closeup of the installed shields - big difference in noise levels!

The third and fourth photos show the TF card slot where I had to scrape some ground plane solder mask for securing it.
In the upper left corner, you can see the push button I installed on the BOOT solder pads.
I know the firmware doesn't support the SD card - yet - but that is what hacking is all about!
Now, I'm waiting to receive the Black (Original design) version with the USB-C connector .
BTW, that old Motorola cellphone battery lasts well over 4 hours.

Hi Ernst,

I have updated with nanoVNA_800_aa_20190705.dfu and no more spikes are present.
Thanks.
Georges.

I have not taken enough 1 port data between the two to state their measurement delta if any. As far as I can tell, the white unit is no different electrically other than the firmware, 2 track display vs. 4 track. Hence the pixel size array on the 4 track firmware vs. 2 track is somewhat finer. My colleague and I are going to update the firmware in the white one so 2 channels are engaged; S11 and S21. Currently, I think I will do some 1 port measurements, the worse (best) test case is measure a 1 dB pad shorted to provide a 2 dB return loss and compare their 1 port responses. That stresses the Gamma value and puts it out at 0.86 reflection coefficient.

________________________________
From: [email protected] <[email protected]> on behalf of Greg Ashley <Gregory@...>
Sent: Tuesday, July 9, 2019 10:51 AM
To: [email protected]
Subject: Re: [nanovna-users] New nanoVNA received

Is this black one, better than the white one? If so, do you have a link to buy it off the ebay ?

-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of alan victor via Groups.Io
Sent: 08 July 2019 19:16
To: [email protected]
Subject: [nanovna-users] New nanoVNA received

Just received my 2nd nanoVNA. This is the black case, no Gecko white which works current to date quite well with 2 track display. This black case arrived ON TIME and well packed. Apparently held it's charge all the way through shipment and booted with a 4 track display.

These instruments are little like a box of cracker jacks or is it chocolate, your not quite sure what's in the box. So far, so good. This unit came in its own plastic protective case with all the accessories enclosed. The construction looks very good and robust. The ON-OFF slide switch and USB-C connector are more robust. There is a screen protector film over the display and no scratches on the display from a stylus being used on the soft screen for pretest. The style of the 50 ohm load is DIFFERENT. The short and open appear the same as with prior cal kit. Is this 50 ohm termination superior? Don't know. The prior was ~ 18 dB best case at 900 MHz. Very important, IT IS CLEAR THAT THE ASSEMBLY OF THIS UNIT HAS THE RF SHIELDS OVER THE BRIDGE AREA AND MIXER AREA AS SUGGESTED IN THE EARLIER POST. ALSO, THESE SHIELDS LOOK LIKE DIE CUT BRASS WITH PRECISION FIT. THESE WERE NOT CUT OUT WITH TIN SNIPS OR A SCISSOR AND HAND SOLDERED IN. THIS LOOKS LIKE A PRO JOB. Hurrah!

There is a green film strip sticking out of the left side of the display. Looks like the kinda of thing you would pull to engage the battery contacts on a new toy to protect the battery during shipment. However, I have not touched it and the unit turns on out of the box. The display has the 4 color traces and the pixel appearance is smaller and crisper than the white gecko unit.

So I will wait for a charge cycle to complete and see how this one plays. Hope this info is of assistance. Alan

Oh well, I guess I spent money for naught?? Maybe I'll save them for another project. I'll check the date code, they still could be old stock
Thanks
Frank

I looked at the part, and they are 602. I'll replace them and add shield cans (there are none) and I paid $75 for this one.
Oh well live and learn

Hi Georges,
those peaks are from the ocsillator circuit. Hugen - great thanks to him for immediate action - has released another firmware nanoVNA_800_aa_20190705.dfu and nanoVNA_800_ch_20190705.dfu which solve the problem,
Firmware, Software and manuals can be found here:

I strongle recommend to update to the latest firmware.

Regards Ernst