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Please excuse this post if it's been covered previously, but with a nanovna-v2 enroute via tindie, I realized I believe it is not fitted with a battery by default. Is the battery specification (part number or dimension, anda any specific additional requirements) available?

Thanks,

73 Dave WB0GAZ wb0gaz@...
(originator of nanovna-users on groups.io, so with precious little time then left to actually play with the thing!)

All nanovna-h sold by us have version number marks on the PCB. Since rev3.4, we have also added version number marks on the shell labels.

hugen

In case it matters - version 0.4.0-2-g7c2f745
No version marking on any of the PCBs as far as I can see (I took off the front and back covers).

Kerr,

I have wound these high ratio transformers using FT50-43 and FT37-43 toroids and always found leakage inductance which affected VSWR, Bandwidth and Insertion Loss. I then read about W8JI's experience with BN73-202 and BN43-202 binocular cores. You get better coupling with these and less leakage inductance. The initial permeability (2500) of the BN73-202 is so high that you only need a few turns to meet the minimum 4X reactance at the lowest frequency. So for a balanced input with a 3000-50 ohm match 1 turn on the primary and 8 turns on the secondary would work well @ 7 MHz. The 73 type material has low resistivity so I recommend that you use kevlar wirewrap wire or Cat5/6 insulated wire becasue enamel wire might nick and contact the core.

Hi all,
I bought a new NanoVNA-H on ebay and received it today. It seems to work, but when I connect it to a laptop using the supplied USB-A to USB-C cable, I get a warning "USB device not recognised. The last USB device you connected to this computer malfunctioned and Windows does not recognise it". I've tried connecting many times, different ports, rebooting, and a different laptop, but always get that message and the device shows up as "not working" in device manager.

I had a quick look at the board, the connections to the socket and soldering of the processor look OK, no shorts that I can see.

Has this been seen before, is there a solution or do I need to buy another one?

Thanks for any advice.

Hi David,

Do you have some information about the maximum dynamic range the pluto can
do in sa/tg mode?




Le dim. 8 mars 2020 à 07:43, David J Taylor via Groups.Io <david-taylor=
[email protected]> a écrit :

For those of you with an ADALM Pluto SDR, here's a 70 MHz - 6 GHz spectrum
analyser & tracking generator:



Looks very interesting. Anyone played with this software?

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

Ground loop due to residual inductance.

EMRFD has a detailed example of what that is and how it can degrade a filter.

Experimental Methods for RF Design, ARRL press.

Allison
-----------------
No direct email, it goes to bit bucket due address harvesting in groups.IO

Any idea when it is available at Ebay. I am lazy and would not want to open one more account to somewhere.

Are any these able to show close sidebands. Like what happens with 1kHz or 100Hz SSB modulation

Thanks for the book page image - this is essentially what I have currently breadboarded up although my toroids are wound for 1.5k rather than 3k. I am going to try removing a turn off the primary side and adding a turn on the secondary side initially as this will give me a 50 to 3k ohm match (well 50 to 2938 ohm).

The other difference is that the output transformer in the image uses an FT-50B-43 and I am using an FT37-43 for both input and output transformers as these are the ones I have plenty of.

Once I have made a few measurements I will then wind new toroids using the Wes Hayward numbers and see how they compare, this should be a 50 to 3828 ohm match. It will be interesting to see what difference the two windings make to the return loss / VSWR and output.

Thanks again for this suggestion.

Kerr,

Wes Hayward (W7ZOI) did some tests on the NE602 (lower temp range than SA602) and published them in his book Experimental Methods in RF Design. The balance input configuration will give you better performance. Here is an excerpt from his book showing the test results and how to wind the transformers....

ground loop or pcb residual capacitance?

I put it online in pdf because that can be read/viewed by anyone.
The pptx format is not compatible with e.g. OpenOffice, and the file is also quite large.

If you want the original pptx file, no problem, send me a mail on my qrz.com email address.
(This also gives me some feedback about who is interested or using my work, hi)

If you want to make a translation into your language, please post it here, so that maybe you can collaborate with others on it.
(and hopefully agree on the fact if the Return Loss is negative or positive ... hi)

73 - Luc ON7DQ

...maybe.

Since last I posted, I've experimented with a variety of possibilities; none of which worked...8^(

But, I reverted back to a message where I mentioned building a filter with half of the circuit on each side of a common copper substrate that didn't have the anomaly.

That construction gave me the idea that maybe there was a ground loop; I'd read about that sort of thing but not for HF. Anyway, I reworked one of the LPF PCBs to put all the RF ground connections on one common plane. Via's were added to connect the planes physically otherwise. The attachment shows an ExpressPCB model.

This corrected the effects for 20m, don't know about 30 yet.



--
Chuck, W5USJ

On Mon, Mar 9, 2020 at 07:31 AM, <mcebokli@...> wrote:

"... I have the cables and standards from the old one, so no problem there."
=================================================================

Marko,
The RG-174 cables and SOL standards delivered with the original NanoVNA are only rated up to 1 GHz. If you intend to use the V2 (SSA-2) to its full 3 GHz capability then you should consider the cost of adding 3 GHz rated cables and standards, in addition to the 3.7V battery.

If you only intend to use SAA-2 at your desktop connected to a PC then a battery is not needed. For portable use I believe either a 3.7V Lion or LiPo battery can be installed. A battery from an unused cellphone would probably work fine.

- Herb

This is great, just what I wanted: the same device, but with wider frequency and dynamic ranges.
I love the smallness of it, same display as before is OK for me.
I have the cables and standards from the old one, so no problem there.
The only thing that hurts is - no battery?
Is there any recommendations for an exact battery type (and link to buy..?)
For what kind of battery is the internal charging circuit designed? I wouldn't dare to put in a different chemistry,
especially as LiPo is famous for caching fire?

Marko Cebokli

I have been reading a bit more about these matching networks and have found another one I think I will try as well.



Starting on page 15 there is a worked example of how to create a 'bandpass matching network to transform 50 ohms to the input of an SA602 mixer'.

Noting the suggestion from the previous posts about balanced inputs I think this particular circuit is unbalanced as all the components are grounded just before the input. I think using this circuit I would put its output to pin 1 of the NE602 and ground pin 2 via a 47nF capacitor (I have seen this configuration in several other examples).

Initially I have modelled this network in SimSmith and adjusted the components to create a match at a frequency of 7.15MHz (as I think this is unbalanced I have used 1.5k ohm and 3pF for the load), the simulation looks good and will be a great starting point for building the circuit for real. I will now test these new ideas out in practise and see which one I think works the best for me.

My reason for doing these experiments is that I find it a great way to learn and I also really enjoy making radio circuits.

If anyone has any additional comments or suggestions I would be extremely happy to receive them.

Resistance (REAL) is a value (at al freqs) and can be plotted on an XY graph on the horizontal axe

IMAG is an? reactance value? (L or C) at a specific frequency and can be plotted on an XY graph on the vertical axe

For any Z there is a REAL+IMAG value at a specific frequency. If you put the IMAG value on top of the REAL value

(as two vectors) you can draw a new vector from (0,0) to (REAL,IMAG)

The length of that vector? corresponds to the impedance at a specific frequency , the angle to the hor axe

is what we call PHASE (Phi)

Below X= REAL? Y=IMAG? r=Z

When writing IMAG values, to distinct them from REALS, we put an"i " in front of it.

The length of z = sqr(x^2+y^2)? y =Z*sin(Phi)? and y= Z*cos(Phi)??? i*i= -1

Want to learn more :? Google "complex numbers"


Afbeeldingsresultaat voor real imag vector som

--
Independent Expert on CE marking
EMC Consultant
Electrical Safety Consultant

From: jafinch78 .

Looks like Signals Everywhere did an overview of mods in his "Adalm Pluto SDR Tutorial: 70Mhz to 6Ghz and Dual Core CPU Modification":

Looks like he has another firmware update video also:

Not sure about normalization and whatever performance verification like calibration pre-processing or smoothing can be done... to improve performance maybe?
===========================

The bandwidth extension and dual-core modifications have been around for a long time, done by many, and on both my Plutos. Yes, the current firmware is required, but it's been some time since it was released. I must confess to preferring information from the source rather than 3rd party videos.



Calibration is included, and seems pretty good. A 10 dB attenuator is added on both TX and RX ports "to improve matching". I don't see any means of receiver calibration. Peak hold is included, but not smoothing or averaging, although I would expect these to be added as the software develops. Would be helpful as can be seen from the attached!

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

My recommendation:

For any ham newby in rf calculating, who is seriously willing to learn,
or who simply wants to optimize his antennas (by using his NanoVNA, or not)
the fastest and (to my knowledge) so far best way is by:

1. downloading Ward Harriman, AE6TY's freeware SimSmith and
2. watching Larry Benko, W0QE's SimSmith Basics videos.

Free download is available here:



Some of Larry's videos may be found here (and after that you can google for many more):



SimSmith probably is the most advanced rf design Smith Diagram software available today.
It is not yet finished though, not 100% free of errors, but in the process of constant improvement.
For any serious ham or RF Engineering student it is a "must have".

73, Hans
DJ7BA





-----Ursprüngliche Nachricht-----
Von: [email protected] <[email protected]> Im Auftrag von Bob Albert via Groups.Io
Gesendet: Montag, 9. M?rz 2020 04:07
An: [email protected]
Betreff: Re: [nanovna-users] Dumb question: What are REAL, IMAG, and PHASE good for? #general_vna

Good questions; unfortunately the answers can get involved.
Yes, real and imaginary are resistance and reactance. Usually in Ohms. Reactance is Z sin(phase angle) and resistance is Z cos(phase angle). The display may only give the angle; I'm not sure.
You can use the phase angle plot to locate resonance; it jumps sharply at that frequency, more sensitive than trying to sweep around to find where it crosses the resistance axis (Smith chart).
Much can be learned by fiddling with it.
Bob K6DDX