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The attached image indicates you are measuring from 50 to 52 MHz, not 1.9
to 450 MHz.

Dave - W?LEV

--
*Dave - W?LEV*
*Just Let Darwin Work*

Thanks, DiSlord for this! It's awfully close, and granted, for precision accuracy remember that we're comparing a $50-$75 device against oscilloscopes or spectrum analyzers which cost many times that....You get what you pay for, most of the time anyway. Tuning duplexer cans isn't for the faint of heart, but the NanoVNA will get you close enough to get into the ballpark.

On Mon, Dec 20, 2021 at 07:21 AM, Jim Lux wrote:

#2 The 28 MHz oscillator in the NanoVNA isn't necessarily accurate enough.? I
don't recall the spec, but let's say it's on the order of 10 ppm (good for a
TCXO) - at 147 MHz, that means it could be off by 1470 Hz.

( #window-197633454 )

My fw allow made internal 26MHz TCXO correction (see CONFIG->EXPERT SETTING->TCXO)
Power on device, set 26MHz CW output
Wait near 5-10min for device warm
Measure output frequency
Enter this value as TCXO
Save confog.

Now as minimum up to 100MHz Nano have only +-2Hz error. (Error bigger on more high frequency)

On 12/20/21 12:27 AM, Earle Wilkinson wrote:

Earle D Wilkinson
(6Y5EW)

Home page:
Email address: earle.wilkinson@...
Echolink: 6Y5RA

On Mon, Dec 20, 2021, 3:18 AM Earle Wilkinson <earle.wilkinson@...>
wrote:

New at this.

I got myself an NanoVNA 2 version 4.
Everyone says best thing ever happened.

Better than sliced cheese.

My problem is that I a sticular when it comes to accuracy.

I would like to check my club stations duplexer accuracy on 147.960 high
pass filter with 147.360 as the split on the low pass filter, that is minus
600 kc split.

Now her is my problem I can only set my markers at 147.300 and 147.900.
Not the exact repeater frequency.

Will the difference of 60 hz make a difference in the accuracy of the
tuning insertion loss etc.

I realise that I need to be accurate at least with the 50 ohms impedance.

Thanks for your response.
Earle D Wilkinson
(6Y5EW)

Home page:
Email address: earle.wilkinson@...
Echolink: 6Y5RA

Two issues that arise:

#1 The NanoVNA only has a limited number of frequency steps (101,201,401, depending on which firmware and model) unless you're using software on an external computer that does multiple scans. So, if you set your span to, say, 147 to 148 MHz, then you'll get a measurement every 10 kHz (with 101 points).? Solution here is to use one of the many software packages that will talk to the NanoVNA and make multiple scans and combine them.

#2 The 28 MHz oscillator in the NanoVNA isn't necessarily accurate enough.? I don't recall the spec, but let's say it's on the order of 10 ppm (good for a TCXO) - at 147 MHz, that means it could be off by 1470 Hz.

Kingston 8Gb HC Card.

As i see log, no any card installed:

38.945 rx: SD_WaitNotBusy CMD0 err, 00

This string mean Nano Ask for card, and no any answer

- Check the correctness of installation in the slot, the card should be contacts to the board and completely recessed into the connector (outside should be 1-2mm)
- Card not answer - need check card contacts to MCU (see H4 schemantic) and power (sould be 3.3V)
- I hope you have original H4 (some clones have diffirent LCD molule, this module not allow read from card)

On 12/18/21 8:19 AM, JF1XCV wrote:

Hi All!

I am now evaluating a 1:6 UNUN with NanoVNA that I bought quite recently. The UNUN is made of two stacked FT240-61 and 1.6mm copper wire with 100pF capacitor in the primary. To measure SWR, a 1800 ohm carbon resistor is soldered in the secondary side. To my surprise, SWR is 1.0 from 1.9MHz to 430MHz. I suspect I misunderstood how to measure SWR with NanoVNA. I am attaching the screen of NanoVNA Saver. Any comments are welcome. Thank you.

You have a transformer with 36:1 impedance ratio, and an 1800 ohm load.? You should see 50 ohms on the other side. That is pretty close to what you see.? What were you expecting?

Good afternoon.
The same problem with saving to the card.
Kingston 8Gb HC Card.

Jens,

1) there is the odd Doll on this group as well as [far too many, /pro rata/] Guys

2) for the technical question, imagine that there are *2* oscillators active, one at f?, one at f?+IF, where IF is an intermediate frequency and f? is the measurement frequency. Then, as square waves, the measurement oscillator will produce frequencies f?, 3f?…, and the local oscillator will produce frequencies f?+IF, 3f?+3IF… Then at the fundamental frequency, the difference frequency is IF, but when the third harmonic products mix, the difference frequency is 3IF. The products at 3IF will be rejected by the post mixer bandpass filter.

3) similar arguments apply when harmonic mixing is employed, such as for the 300?MHz - 900?MHz range. Note in this case, that there will be an unwanted product from the fundamental frequencies at ?IF (hence the use of a bandpass, rather than lowpass, filter) and the 5^th harmonic at 1?IF.

Also note the reducing power in the harmonics, thus doubly reducing the mixer products to be measured. The fact that any of this works is a triumph of human ingenuity and DSP.

4) Identifying all the frequencies and corresponding mixing products for n^th harmonic operation is left as an exercise for the interested reader!

HTH, 73, Stay Safe,

Robin, G8DQX

PS: For this sort of hybrid analogue & digital machine, often the block diagram is more informative than the circuit (schematic) diagram. The actions of the software are also key components.

Hello Guys,

I've one question which puzzles me, and was unable to find information neihter in the forum nor in the Wiki.
Since the NanoVNA outputs a rectagular signal which's harmonics are not neglectable and has no selective input (what I can see from the schematic is broadband), how can the S12 and S21 measurements be accurate as all the harmonics of the output will go into the mesurement at the input.

What do I have overseen?

Thanks for bringing me on the right track

Jens DF9HJ

I see in NanoVNA-Saver screenshot frequency range 50-52MHz

Earle D Wilkinson
(6Y5EW)

Home page:
Email address: earle.wilkinson@...
Echolink: 6Y5RA

On Mon, Dec 20, 2021, 3:18 AM Earle Wilkinson <earle.wilkinson@...>
wrote:

New at this.

I got myself an NanoVNA 2 version 4.
Everyone says best thing ever happened.

Better than sliced cheese.

My problem is that I a sticular when it comes to accuracy.

I would like to check my club stations duplexer accuracy on 147.960 high
pass filter with 147.360 as the split on the low pass filter, that is minus
600 kc split.

Now her is my problem I can only set my markers at 147.300 and 147.900.
Not the exact repeater frequency.

Will the difference of 60 hz make a difference in the accuracy of the
tuning insertion loss etc.

I realise that I need to be accurate at least with the 50 ohms impedance.

Thanks for your response.
Earle D Wilkinson
(6Y5EW)

Home page:
Email address: earle.wilkinson@...
Echolink: 6Y5RA

Hi All!

I am now evaluating a 1:6 UNUN with NanoVNA that I bought quite recently. The UNUN is made of two stacked FT240-61 and 1.6mm copper wire with 100pF capacitor in the primary. To measure SWR, a 1800 ohm carbon resistor is soldered in the secondary side. To my surprise, SWR is 1.0 from 1.9MHz to 430MHz. I suspect I misunderstood how to measure SWR with NanoVNA. I am attaching the screen of NanoVNA Saver. Any comments are welcome. Thank you.

Henry JF1XCV

After connectiin to PC, NanoVNA must see as additional COM port, you can check this in device manager.
If no additional ports in, check uncnown devices, and update drivers.

For USB connection baud rate not used (ignored)

Larry,

Sorry to see that your post got hijacked and went off topic!

I want to than you for the work you did putting this DiSlord updates document together. Very interesting to see how the firmware has evolved.

Roger

My document is NOT on that website. The owner of that website attempted to hijack my thread and drive views and probably advertising revenue for himself.


On Sun., 19 Dec. 2021 at 4:34 p.m., Rick Murphy<k1mu.nospam@...> wrote: The language isn't changing because there is no English translation of this
article on the site.
The language choice menu "works" for content that has an English version,
and doesn't when it doesn't exist.
73,
? ? -Rick


On Sun, Dec 19, 2021 at 2:39 PM Donald S Brant Jr <dsbrantjr@...>
wrote:

Re:? language not changing, I have noticed some other sites where this is
happening, so there may be a more widespread issue.? Amazon Web Services
had an outage a week or so ago, and I noticed little things which were
broken a few days after; maybe it is happening again.
73, Don N2VGU

--
Rick Murphy, D. Sc., CISSP-ISSAP, K1MU/4, Annandale VA USA

On Sun, Dec 19, 2021 at 09:41 AM, Richard Groot wrote:

So (newbie here) I've seen some versions of nanoVNA that capture 1000 data
points rather than 101. What are the consequences of the larger number of
points?

Disadvantage
- with more points you get a slower sweep time.

Advantages -
- with more points the step size for a given frequency range is smaller so you get more plotting "definition". When measuring an antenna, for example, this will give a better estimate of the frequency with minimum SWR.

- also you can "zoom in" (without recalibrating) and get better results if you have more data points. For example if you have 401 calibrated points over frequency range "A" and then zoom in by a factor of four to frequency range "B" 100 of the points will be close to what you get if you calibrate and measure over frequency range "B" with a 100 point sweep. Three interpolated points will be also available.

Roger

DisLord

excuse me for using your post. I need a clue why Nanovnasaver will not connect to usb port on my win 7 machine.

I have win-7 SP1 plus C++ and Net+ installed and I also ran the Cypress USB installer.

On the saver application no comm ports show up and typing in the allocated port number does nothing.

The QT version always connects OK.

I spotted your post re the app by one-of-eleven and downloaded that program. It connects ok too?

Checking the uSB port settings, the only difference between Nanovna saver and the above application is the baud rate?

So I am not sure what to do next, any ideas?

regards

joe

You not install 32768 quartz for rtc

If you not plane install it, remove battery, wait 10sec and put it back.
This reset lse mode to lsi

The language isn't changing because there is no English translation of this
article on the site.
The language choice menu "works" for content that has an English version,
and doesn't when it doesn't exist.
73,
-Rick


On Sun, Dec 19, 2021 at 2:39 PM Donald S Brant Jr <dsbrantjr@...>
wrote:

Re: language not changing, I have noticed some other sites where this is
happening, so there may be a more widespread issue. Amazon Web Services
had an outage a week or so ago, and I noticed little things which were
broken a few days after; maybe it is happening again.
73, Don N2VGU

--
Rick Murphy, D. Sc., CISSP-ISSAP, K1MU/4, Annandale VA USA

Hi
I have installed the latest version on my Nanovna H v3.2
Everything seems OK except that I can not save date and time.
In VERSION , time is 2000/01/01 00:00:30 (LSE) and I can not change it

Any idea?
Regards, Corneliu