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What’s the difference between the Deepelec and the many s**t boards offered at AliExpress, besides the higher price?

am i the only person with this issue?,as it stands its pretty unusable,at least for me thats the case!

@Gary O'Neil, N3GO - 2 December 2019
/g/nanovna-users/message/7680

Dear Gary,

It is very nice, indeed, to hear from you again !

Well, regarding your specific request, allow us, please, to suggest you to try:

[Windows][Start][Accessories][Paint][Image][Invert Colors]

Best regards,

gin&pez@arg

Hi pgc1682
Agree it is the better than nothing and that is what Rune said.
To do any attempt to use literature form Keysight an try to implement such tools and utilize complex coaxial line models is in my opinion a mistake in connection with the NanoVNA. I think you are forgetting that the industrial VNA's has an entirely different sort of calibration with adaptor mismatch fully compensated. The NanoVNA has amplitude jumps when switching from fundamental mode and between the various harmonic mode. Although the embedded firmware tries to compensate it still is make such model sort of useless. However when using quality and in particular short cables for Delay offset is so bad, and result will be pretty OK.
I have done a 50KHz to 500MHz test for a 18GHz 1 meter long professional male male cable with professional 3.5mm male adaptors (not SMA so no Teflon isolation) VF 0.75 where the yellow trace is when um terminated with a fringe offset delay of 1.35ps and the white trace terminated with a 0ps offset short termination. AS you can see the reflection coefficient and the phase trace does not look some a coaxial line model can handle and offset.
The same test done for the 20cm long test cable supplied with the NanoVNA. Its traces look very much line a cable not being 50 ohm
So that was to days experiment judge yourself
Kind regards
Kurt


-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af pgc1682@...
Sendt: 5. december 2019 13:59
Til: [email protected]
Emne: Re: [nanovna-users] New version of NanoVNA-Saver: 0.2.1

Hi Kurt Poulsen,

I understand you, but something is false. Best way the fully calibrated instrument. But if not available, for example if can not do osl far end calibration port extension useful. This is exist industrial vna too. See keysight notes. Of course not ideal. But better than none. Many complex coaxial line model and correction available.

Bob -

Please DO NOT apply 5 volts to the device if you have the battery connected directly to the power switch!!

You WILL end up with a battery fire.

The only reason the unit is working is because there is a low drop out regulator that is converting that 3.7 volts down to 3.3 volts.

HOWEVER - your SA612 mixers are no longer getting the 5 volts they need to operate with and your readings will not be accurate.

The 5v at the USB socket drives the charger/inverter chip that simultaneously charges the battery and provides 5 volts to the power switch to run the Nano.

I've used an existing forum photo and added the spot (red) where you can manually connect +5V to R40 at Pin 1 of the IP5303 chip.
But first, put the battery back where is is supposed to be connected.

you can use a barrel jack and a 5V wall adapter and you're good to go.

I'm using ComTestSerial from microridge.com. The best of all, it free! :-)

73's de Karl LA3FY

I measure transmission loss by reading the display numbers when the marker is at the desired position.? If the line is open or shorted at the far end, the R reading in Ohms will indicate loss, as it would be infinite at zero loss.? A reading of 500 Ohms would indicate 10% loss I assume.
A lossless line shows as a trace at the outside edge of the Smith chart.
Bob
On Thursday, December 5, 2019, 02:56:59 AM PST, Oristo <ormpoa@...> wrote:

if I use CHO/CH1 to e.g. check a CMC and I select LOGMAG for CH1 is it then
true that LOGMAG will show transmission loss

If
* CMC means Common Mode Choke
* connections are e.g. Fig 3 (a) in
* CH1 was first calibrated without CMC
then that will yield transmission loss for common mode choke.

.. but if connected as Fig 2 (b) with CH1 as LISN, then measurement is
e.g. transmission loss for conventional coax that happens to have a CMC.

In theory, one could connect CH0 and CH1 centers to shield and center of one end of transmission line
and terminate the other end, as in Fig 2 (a).
With matched termination and without CMC,? CH1 would ideally show infinite loss,
so effectiveness of CMC is by lack of loss, so to speak.

Erik,With the battery disconnected I connected 3.7 V to the off position of the power switch and it works.
If I raise it to 5V and connect the battery, will it charge and operate on battery?? I would like to restore normal battery charge and operation.
Bob

Rune,

I appreciate all the work you have done developing and sharing this program. Really looking forward to the next version of your program when you have fully implemented the "offset delay" feature. It is a useful thing to have when using port extenders (connector savers) or when adding short, quality adapters to a previously calibrated setup. Those attempting to use it to compensate for cable length will need to consider the issues associated with cable loss etc. discussed above and use this feature with caution.

Thanks all for the sage advice, and yes, I do have some cheap dummy loads on order from Amazon - but darn it they only had overnight delivery for a shipping option - lol. So yes, my impatience overcame rationality, and I pledge not to re-purpose the SOL kit. Oh and yes, it's for HF bands only, 3-30 Mhz on a WSPR mode transmitter.

Thanks Oristo,

That helps. Also, I found a couple of different ways to use the Fire as a monitor. A couple require paid for apps and a couple more use remote desktop software to do it. Going to give them a try.

BruceN / K4TQL

From: hwalker

Bruce,
[]
On the flip side, the cost of the NanoVNA is magnitudes below a commercial VNA so you can take a lot of liberties; however, its always a good idea to adhere to "best practices" even when they seemed inconsequential.

- Herb
=================================

Agreed.

Likely many of the loads are likely to be these devices or similar:



These claim "2W" and "6 GHz", both of which I would take with a pinch of salt!

Cheers,
David
--
SatSignal Software - Quality software for you
Web:
Email: david-taylor@...
Twitter: @gm8arv

Yes I followed the installation procedure to the letter, the problem appears to be associated with Python3.7.4 not loading Pip correctly.

Simply a bad idea and in general a bad practice!
Precision terminations in general are small low parasitic devices not designed to dissipate power.

You do not mention the operating frequency but if HF you can readily parallel some 1/2 W 100 or 220 ohm R,s and get decent return loss with proper construction.

Alan

On Thu, Dec 5, 2019 at 07:18 AM, Bruce KX4AZ wrote:

I am tempted to re-purpose the 50 ohm calibration piece from the OSL set as a "dummy load" when testing a low power (300 mW) RF transmitter. Does anyone have any idea what the power dissipation limit might be for a typical calibration item like this?

======================================================================================
Bruce,
As an aside, one of the technicians at the lab that I worked for was banned from using the lab's network analyzers because he temporarily "borrowed" the 50 ohm load from a VNA cal kit and used it as a terminator for a receiver input. The calibration of your VNA is dependent on the quality of the OSL standards used. The standards should be treated and stored carefully and not used for other purposes, especially other purposes that apply power to them.

On the flip side, the cost of the NanoVNA is magnitudes below a commercial VNA so you can take a lot of liberties; however, its always a good idea to adhere to "best practices" even when they seemed inconsequential.

- Herb

And if it HF or even VHF- build your own.

Dale W4OP

I think 0.3W may be critical for L calibration load.

What is reason to try to use expensive precise calibration load as a high power dummy load, while you can buy cheap 5-10W dummy load on aliexpress?

For example:

I am tempted to re-purpose the 50 ohm calibration piece from the OSL set as a "dummy load" when testing a low power (300 mW) RF transmitter. Does anyone have any idea what the power dissipation limit might be for a typical calibration item like this?

I never thought about using a Fire as a larger display. Larry, you speak of "side loading" an app. Pardon an old dude but I don't know how to do that. Are there instructions somewhere on how to do that. I could look it up, I guess, but asking someone who knows is quicker.

As a side thought, is there a way to turn the Fire into a monitor (display) for other applications say, like, connecting a Raspberry Pi to it?

BruceN, K4TQL