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OK, so I see quite a lot of firmware updates appear to include 1500Mhz now.

Is it really usable ?

About 6 weeks ago or whatever when I last read about the trials, the trials of the Nano VNA's useablity
really appeared to be about 900Mhz, and attempting anything higher was a step too far.

Has something changed, or is 1500Mhz just appealing to vanity ?

Honest question, because if it is usable then I may revisit the idea of a firmware upgrade.

73 de Andy

That is a good questiion. So much happens between 900-1000 MHz. I use LoRa in home automation and could make good use of that range. The 900 MHz just missed.

--
*Doug Basberg, N8VY*

The short answer is: It depends.

Tuning the S21 of a filter: yes, but not the stop band as there is very little dynamic range. There is a trick to gain 20dB. Tuning a filter has been demonstrated up to 2.1GHz
Measuring the impedance of an antenna: Doubtful. The nanoVNA measurement bridge loses directivity quickly above 800MHz. I could not tune an antenna at 886MHz
You may have luck when running on battery. Connecting to a PC during measurement makes performance above 600MHz worse.
--
Erik, PD0EK

Hi Andy,
Well it can be used more or less up to about 1200 MHz, but the returnloss dynamic range from 900MHz to 1500Hz decreases from 30 dB to 8 dB.
Jos

My understanding is that hugen pulled the initial firmware that allowed operation up to 1500 MHz because performance was so poor (probably especially true for those NanoVNA with oscillator chips that have trouble operating to 300 MHz). Subsequent firmware developers found they could get useable range extension by a change of mixer stimulus.

I have two NanoVNA's and have updated both of them to 1500 MHz operation. Above 900 MHz most of my measurements are s21 thru-loss. Between 900 MHz and 1 GHz I have about 30 dB of useable s21 measurement range on both NanoVNA's. Above 900 MHz increasing to 1.5 GHz the s21 measurement range gradually falls off to 20 dB on both units.

On each of my NanoVNA's, S11 measurements are acceptable up to 1 GHz but start to become suspect >1.2 GHz.

I consider the firmware upgrades (currently using hugen's 0.2.3 version) to be worthwhile for my two units. I might also add the new NanoVNA-H that hugen is marketing has the 1500 MHz firmware installed. So he must believe it is stable enough to use in his commercial product. The last thing he would want is bad marketing by including firmware that doesn't perform well.

- Herb

it works, not very good, but at least you can use it to see overall performance your antenna or filter.

When you have choice to use up to 1500 MHz with limited dynamic range, this is definitely better than no choice at all :)

OK thanks everyone for your replies.

I'm not exactly seeing overwhelming evidence that I should upgrade to a 1500Mhz firmware.
I'd probably be better off with an old GDO and a field strength meter up there ;-)

73 de Andy

Hi Andy,
upgrading to a higher frequency range doesn't lose you any other features,
and you don't *have* to use it ;-) But the newer firmwares DO contain
bugfixes, and new features. QRP RX has been very active in fixing errors
and improving the readings of the NanoVNA. So even if you won't use it at
1500MHz, do consider upgrading. :-)

--
Rune / 5Q5R

On Sun, 10 Nov 2019 at 17:47, Andy via Groups.Io <punkbiscuit=
[email protected]> wrote:

OK thanks everyone for your replies.

I'm not exactly seeing overwhelming evidence that I should upgrade to a
1500Mhz firmware.
I'd probably be better off with an old GDO and a field strength meter up
there ;-)

73 de Andy

If you want performance into the microwave range I'd wait for the nanoVNA V2:

<>

Mike N2MS

On Sun, Nov 10, 2019 at 02:49 PM, Andy wrote:

OK, so I see quite a lot of firmware updates appear to include 1500Mhz now.

Is it really usable ?

73 de Andy

There are many versions of nanoVNA on the market. My black nanoVNA is fine up to 900 MHz. At frequencies above 1 GHz the track is dirty, uneven, unusable compared to other instruments.
Lucio, I0LYL

To put some facts in this discussion I measured the S11 of a a 25 ohm resistor from 0.5MHz to 1500MHz.
The nanoVNA was connected via USB to a PC but running from a clean 5 Volt supply and TX power is fixed at 2
The light blue line in the first picture starts at 25 ohm at 0.5MHz and stays at aprox 25 ohm till around 1100MHz
Also the phase is stable so nanoVNA is usable for S11 till at least 1100MHz.
Although the calibration till 1500MHz looks good (see second picture for S11 if a open just after calibration) real measurements no longer have a lot of relevance, most probably due to some non-linearity in the mixers above 1100MHz
--
Erik, PD0EK

On Sun, Nov 10, 2019 at 06:47 PM, Andy wrote:

I'm not exactly seeing overwhelming evidence that I should upgrade to a
1500Mhz firmware.
I'd probably be better off with an old GDO and a field strength meter up there
;-)

As Rune mentioned above, 1500 MHz is not the main goal for newer firmware. The main goal is to fix errors, bugs, make more stable and more precise measurements, add new features (such as TDR and Group Delay track, which is missing from old firmware).

For example, old firmware have terrible spikes at 300, 600 and 900 MHz, also it returns unstable measurements and errors, sometimes it freezes and don't respond, it don't allows to enter exact frequency and may show wrong frequency (not these which is actually used).

In addition, old firmware don't allows to check Crystal filters, because it has limitation for minimum frequency span.

If you are ok with firmware which has a lot of bugs and errors and don't needs to measure filters, don't needs TDR and Group Delay track, you can stay with old firmware :)

Regarding to 1500 MHz range, new firmware is just allows to use it, but you can setup 50 kHz - 900 MHz range and it will works the same as old firmware. With exception, that a new firmware will have less bugs and errors. The new firmware just allows to use extended range, but if you don't want to use it, you can just don't use it. Just setup 50k - 900 M and it will works the same as old firmware.

For example NanoVNA-Q:
allows to use frequencies from 10 kHz. It works well from 10 kHz. For example, I tested ultrasonic transducers which working on 24 kHz. You can see in attachment. And as you can see I can check resonant frequency (24100 Hz) and even sound wave propagation delay between TX and RX ultrasonic transducers. Note, this is frequency range 20 kHz - 30 kHz :)

It will be just impossible with old firmware

Thanks everyone for the info.

I have what appears to be a two trace version, 900Mhz, and to be honest it appears to be satisfactory.

No crashes etc.

Although there is one thing that I have not yet played with, and that is how to sweep a small signal range for xtal filters.

I have heard that there are frequency rounding errors on some versions, but I cannot determine if I have that issue because
I'm not sure how to set it up for a sweep, and advice greatfully received.

Not too fussed about a battery indicator, since I think it already has one, if I turn it on and there's no display then battery = dead ;-)

I quite like the idea of an auto find lowest SWR etc function, that could be useful, but no deal breaker, I just zoom in a bit more.

So, I guess that I may have aplay at some time,but I'm not in a rush.

73 de Andy

I have heard that there are frequency rounding errors on some versions,
but I cannot determine if I have that issue because
I'm not sure how to set it up for a sweep, and advice greatfully received.

If you are using original firmware and touchscreen control, then this map shows
where to set START and STOP frequencies (under STIMULUS)


These settings can be saved, either under CAL or RECALL / SAVE

Mine appears to be 100Hz steps.
Test method, use receiver, listen to span set for 300Hz and I can hear 3 distinct tones.
Does the newer firmware use lower steps ?

73 de Andy

Hi Andy,
it does. Down to 1Hz, I believe?

--
Rune / 5Q5R

On Mon, 11 Nov 2019 at 15:21, Andy via Groups.Io <punkbiscuit=
[email protected]> wrote:

Mine appears to be 100Hz steps.
Test method, use receiver, listen to span set for 300Hz and I can hear 3
distinct tones.
Does the newer firmware use lower steps ?

73 de Andy

Does the newer firmware use lower steps ?

QRP firmware can set 1Hz steps

1Hz, wow, that's pretty cool.
I won't write off an upgrade in the future then.
73 de Andy

On 11/11/2019 15:13, Andy via Groups.Io wrote:

1Hz, wow, that's pretty cool.
I won't write off an upgrade in the future then.
73 de Andy

No don't, I found it really useful for checking an ADS-B RX antenna at 1090MHz. (jpole with 1/4-3/4 wave balun and shorted 1/4 wave stub filter for rtl-sdr dongle))

See attached.

That output was with the antenna un-tweaked after building from nec2c dimensions - very impressed with the results.

Cheers,
Barry
G4MKT

Attached is the print screen of the 50 Ohm load?sweep up to 1.4 GHz
73 de YO4AUL