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Mine was shipped apparently on 17Jan2020 to Mauritius. I hope to see it soon!

Neal,

With the nanovna-saver software you can display up to 6 sweeps with combinations of 6ea S21 and 16ea S11 and 1 combo S11/S21 options.

Don't know about the unit itself options.


--
Chuck, W5USJ

On Tue, Feb 18, 2020 at 05:31 AM, Pierre Martel wrote:

I ordered a Nanovna H4 from alibaba begenning of the month, she told me it
would ship before the 15, but did not had any news since.

Am I the only one?

I got a message from her on 2/13 that they where finally resuming shipments, after the recent holidays and the CVE outbreak.

Just a thought regarding SMA connectors. When I worked on NASA projects,
the mandate was 20 connects and disconnects and the connector(s) was
removed and discarded. They are excellent connectors from an RF
standpoint, but certainly not as rugged as those larger connectors we are
used to.

Dave - W?LEV

Dave - W?LEV

--

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

I've had that a few times too. I've never been able to figure out why but recalibration seems to always get it going again. Not much help other than I've had that too. I only need the 3 calibration steps but I want to say I've noticed it at least once when I don't complete all the calibration steps. Not everytime though.

Courier services in China are resuming, you can contact Maggie at sales11@...

hugen

Nels, I should have said Hi-Z broadband transmission lines. Of course the tube amp situation is as Dave stated. I went to to calculate the spacing for the ladder line.
I was amazed at how rapidly it increases with the impedance. The line-to-line capacitance requirements just get really small. According to the equations presented,

300 Ohms --> 0.3 "
450 Ohms --> 1"
700 Ohms --> 8.5 "
1000 Ohms --> 105"

I'm very impressed with the nanoVNA, but with the 50 Ohm bridge design, I would not expect to achieve good accuracy at measuring at greater than 10 times the bridge Z, especially at higher frequencies.

I ordered a Nanovna H4 from alibaba begenning of the month, she told me it would ship before the 15, but did not had any news since.

Am I the only one?

It's not just the Jog Switch it's also the way it is polled by the software.

Replacing the jog switch with push buttons improves the operation, mainly because at least you can feel the positive click as a confirmation, but it doesn't entirely fix it.

/g/nanovna-users/topic/34384144#3863

Regards,

Martin - G8JNJ

I am no longer in front of the device, but I am pretty sure there was CH0 preceding all 3 of the active trace readouts (RL, SWR and Smith).
Is there anything else that could have prevented the SWR trace to be non active?

Thanks for the input.

Some jog switches are of poor quality but you can determine if it's the firmware by flashing a different developer's version other than edy555 FW.Flash QRP's firmware - he does not have the marker freq change feature using the jog switch.
If the same thing happens, it's the jog switch - if not, it's the firmware.
Did you read edy555's release notes for the 0.5.0 release that I posted?

I think now, after reading posts about this same problem, that it is not the switch which causes problems, it is the jog wheel itself working illogically (in my opinion, that is)

If you have some spare fibreglass (FR4 PCB material or even an old PC board (strip the parts)) just create a small bracket to hold the SMA connectors in place.Cut, drill and slide the bracket over the square body of the SMA connectors.No dimensions given due to variations in spacing but it's a really simple build.Nothing more than a drill and small file is needed and you can separate the grounds easilyJust leave some copper around the openings to solder to...
...Larry

I've measured an 9.8k Ohm small THD resistor, using direct measurement on
CH0, and also the S21 method proposed by G3TXQ for measuring chokes:


[image: image.png]

It's obvious that the S21 method is giving much better results. This method
assumes both CH0 and CH1 impedances are 50+j0 Ohm, which is not quite true.
In order to improve that, I used two pcs 6dB attenuators before and after
the 9.8kOhm resistor which was inserted between CH0 and CH1 in series.
Of course, I've performed first a through calibration with the two
attenuators.

Ady YO2NAA

On Tue, Feb 18, 2020 at 10:27 AM Ady, YO2NAA via Groups.Io <yo2naa=
[email protected]> wrote:

Regarding the external bridge, I've asked Rune, the author of
NanoVNA-saver to add external bridge support.


NanoVNA-saver is already an amazing tool, I really appreciate the great
work of all developers of FW and SW related to NanoVNA.

Ady YO2NAA

On Sun, Feb 16, 2020 at 11:39 PM hwalker <herbwalker2476@...> wrote:

I agree with Kurt that the NanoVNA's inaccuracies above 300 ohms are
not that bad. I had the same frustrations with an HP Agilent 8753C

Network

Analyzer with 85046A S-Parameter Test Set. Once you get very far from 50
ohms its accuracy also suffers. An HP applications engineer I contacted
explained that's pretty much the nature of the beast for any low

impedance

50 ohm VNA, and there's no reason to expect any more of the NanoVNA. As
Kurt said, the test fixture also plays an important part in measurement
accuracy, especially above 1 MHz. Flying leads test fixtures basically
only work for quick checks in the kHz region.

Erik wrote a Matlab script,
/g/nanovna-users/message/7685, to use an external

bridge

to calibrate the NanoVNA at other than 50 ohms, but I never saw any
feedback from users who tried using it at 300, 1000, or higher

impedances.

There were actually about 34 messages in the "Using an external RF bridge
with NanoVNA " topic and I don't remember a definitive test procedure
write-up coming out of it.

- Herb

he SWR was always shown completely flat at the bottom of the screen and the
readout for that trace was in fact showing 1:1 as well along the whole trace.

1) be sure that the TRACE selected for SWR is using CHANNEL CH0
2) in SCALE, select whatever REFERENCE POSITION that you like
eg 1 x1
3) select an appropriate SCALE->SCALE/DIV
e.g. .2 x1 for 100 Ohm termination if calibrated for 50 Ohms

Regarding the external bridge, I've asked Rune, the author of
NanoVNA-saver to add external bridge support.


NanoVNA-saver is already an amazing tool, I really appreciate the great
work of all developers of FW and SW related to NanoVNA.

Ady YO2NAA

Hi,

I Ham friend of mine ordered a NavoVNA and he asked me to come over and help him understand how to check the SWR of his antennas. I am not yet very familiar with all the operational procedures of the NanoVNA except for what I could gathered here by reading other posts. But can't seem to remember a similar issue being brought up and a quick search did not help either. Plus I still need to order mine, but have not made up my mind between the v3.4 and the 4H, etc, so didn't have any experience at all playing with this device until now.

What I did first was set the start and stop frequencies (in this case 2-35MHz), then proceeded to make a calibration which included a reset and then seemed to go well on all three steps, as the markers for open, short and 50ohm where all showing in the correct position on the smith chart after the calibration was completed and saved. Afterwards I tried with a narrower frequency range (2-10MHz) then calibrated again, but the results where still the same as described bellow.

After connecting the antenna to CH-0 both the Smith chart and return loss traces seemed to be showing useful indications, but the trace corresponding to the SWR was always shown completely flat at the bottom of the screen and the readout for that trace was in fact showing 1:1 as well along the whole trace. This happened even when the Smith chart clearly was showing a reading of an impedance that was quite different than 50 ohms, plus capacitance or inductance. Besides it would be impossible for a single antenna to have 1:1 on the whole frequency range. Just as a test I connected a dummy load instead of the antenna and then the return loss trace would also be flat, and the smith chart would show the marker very close to where 50ohms would be expected to be.

So my question would be if I am missing to set up something else in order to be able to make the SWR trace work. I tried disabling all other traces but that did not solve anything either. Also not being yet very familiar with practical use of the device, I found that the Scale setting was a bit confusing as it only has the numbers and then a +1 field. Would this be used to define the per division dB value of the vertical scale markings?

Thank you in advance for any pointers.

On Mon, Feb 17, 2020 at 05:41 PM, <nanovnauser@...> wrote:

well looking at the link to owen duffys solution it looks like the ground is common to both connectors then?,cheers all 73
======================================================================

Owen only uses his NanoVNA up to 200 MHz. hugen intentionally separates CH0 and CH1 to improve isolation between those ports at high frequencies. Probably not anything you'll notice if all your testing is below 300 MHz. How much connecting the ports actually degrades the noise floor above 300 MHz is open to question, but hugen in past posts has recommended not doing so.



- Herb

Folks,
Always read the release notes for the version and development release of firmware you've flashed your device with.

In this case, edy555 documented the jog switch changes at this link:



"add lever operations that support shifting center freq, zoom span and marker search"

And they most likely survived to the current release.
This has been documented in my version of the User Guide since last November!