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Hello Erwin, I am quite happy at number 2 ? Good to see you here.

73

Conrad PA5Y

My mistake David.

Conrad

That's the one, many thanks to all.

Regards

Conrad PA5Y

Hello KV5R, sure. Good questions and good points. I'll try to go through your note step by step question with a response.
==================
Rather than constructing, would something like an inexpensive "QRP Antenna Tuner" be a useful accessory for the nano? It's just a stepped inductor and air-variable capacitor, with box and connectors, with a moderate impedance matching range.
==================
YES. AGREE. However, the motivation in building your own is to use the VNA in making certain that the self resonate frequency of each of the matching components are WELL above the application or TEST frequency. Otherwise you are dealing with a frequency dependent L or C. Ideally the L or C maintains a C value or an L value that over its entire variable range is spot on the same value, say at 1 MHz or at 30 MHz! Not all L's and C's behave in that manner! Particularly LARGE HV variable caps have a pretty significant parasitic inductance. Hence their C value will shift quite a bit with frequency despite, you never mechanical change their value! Now normally we don't care about this affect, but if were trying to use the matching network as an instrument, then we may need to take care about this subtle aspect.
========================
Understood. But I think a more typical use-case would be measuring at the end of the feed-line (typically low-loss open-wire parallel "ladder line"), as for high-Z non-resonant antennas, the feed-point impedance is rarely meaningful, and the transmission line impedance varies with length and frequency. I suppose one might measure it at the feed-point if the desire is to design a tuning stub or other Z-match device at the feed-point.
==========================
YES! I tend to look right at the antenna feed point. Yes, the series lines and stubs will further modify this Z. But that is part of the MATCHING PROBLEM. Our first challenge is to find the accurate Z at the antenna driving point. So that's where the little high performance matchbox tuner comes in. If we adjust this tuner to obtain a super return loss at its 50 ohm port where our VNA is connected, then the TUNER contains the information we seek, namely the antenna impedance!
===================================

I'm not understanding how to connect and use the nano to determine the L and C values of this little L-network. I assumed one would need an LC meter for that.
============================================
WELL, you are not. However, you are using the VNA to assist in the construction of this well performing tuner whose readout of C and L values (assume a simple L network) are ACCURATE. So you need to carefully characterize the C and L's used in the tuner construction to eliminate as much parasitic from their design. Remember, we are not designing a tuner to handle any power! We are designing a tuner to have stable impedance characteristics. Hence small array of C's or piston caps and an array of tapped air wound L's would be suitable. Recall, the tuner is being driver by the nanovna which has feeble power!

==================================================

Knowing the L and C values required to achieve the good return loss permits you to calculate the antenna Z.

==================================================

WHEN the L and C's of the tuner are set to produce a high performance return loss as measured by the vna, then in essence, if the tuner were terminated (where the vna was positioned) with 50 ohms and we were to look into the TUNER where the antenna was connected, we would see the ANTENNA Z CONJUGATE. Wow, that's a mouth full. The best was to see this is to do an example problem and a simulator like LT Spice is a nice tool to learn. Or there are other SMITH GRAPHIC programs that are quite helpful to assist in this process. Standby and I will see what I can assemble.

Alan

The unit is defective as there is no timeout built into the firmware.?
What you are seeing is a defective battery charger chip that are found on units from certain Chinese manufacturers.?
Contact the seller and tell them to either exchange the unit or take it back for a full refund.?
Do a search on the forum for ip5303.?



On Mon, 18 Nov 2019 at 4:40 PM, Dick W0QM<richard.n.grubb@...> wrote: I received a new 2.8" NanoVNA about a week ago purchased on eBay from a US supplier "thanksbuyer-hobby" . It appears to be complete but without an EMI shield. I have calibrated and used it successfully with both the Win 10 and the Android Apps. However when used standalone without a charging cable connected it consistently times out with a blank screen after about 20 seconds. The battery signals it is fully charged and the device will restart reliably after about 10 seconds.Has anyone else experienced this and knows how to fix it ?

I do not know how to discover what firmware is installed. What is the best stable release to load ? I have the shorting pins installed and the ST loader appears happy. I have created a dfu file from the 050 release of two days ago but I am nervous about loading it in case I missed some important step in creating the dfu image from the published hex file using the ST utility. How reliable are the firmware utilities ? Should I worry about bricking the processor with a bad load overwriting the utility code in the processor ?.

Thanks for any advice.

I received a new 2.8" NanoVNA about a week ago purchased on eBay from a US supplier "thanksbuyer-hobby" . It appears to be complete but without an EMI shield. I have calibrated and used it successfully with both the Win 10 and the Android Apps. However when used standalone without a charging cable connected it consistently times out with a blank screen after about 20 seconds. The battery signals it is fully charged and the device will restart reliably after about 10 seconds.Has anyone else experienced this and knows how to fix it ?

I do not know how to discover what firmware is installed. What is the best stable release to load ? I have the shorting pins installed and the ST loader appears happy. I have created a dfu file from the 050 release of two days ago but I am nervous about loading it in case I missed some important step in creating the dfu image from the published hex file using the ST utility. How reliable are the firmware utilities ? Should I worry about bricking the processor with a bad load overwriting the utility code in the processor ?.

Thanks for any advice.

On Mon, Nov 18, 2019 at 11:59 AM, David KD4E wrote:

Isn't there a 3rd path - the "2"? "H" has the best firmware but older
hardware & small display, "B" larger display & some hardware updates, but
older firmware, "2" about to release newer hardware & firmware but small
display. Sure wish they'd combine efforts.

===============================================================
David,
Currently we have the following products being sold:
1. 2.8" NanoVNA (Hugen's MOD of edy555's original open source project). All 2.8" devices marketed as" NanoVNA" are also clones of the open source project.
2. 2.8" NanoVNA-H (Hugen added the "-H" suffix to his product to distinguish it from other clones being sold.) His NanoVNA-H product also has a plastic case, has the diode mounted for battery voltage monitoring, has proper USB-C terminators and the firmware has been upgraded to at least ver 0.2.3.2. Cost is still around the US $50.00 range.
3. 4.3" NanoVNA-F (BH5HNU's NanoVNA with a larger screen, different operating system and different firmware.)

Version 2 NanoVNA's probably won't appear on the scene until into the New Year. There is not a lot of incentive for cooperation. Each product designer has a small window to re-coop his or her efforts before the cloner's reverse engineer their pcb designs and cut their profits.

- Herb

Isn't there a 3rd path - the "2"? "H" has the best firmware but older hardware & small display, "B" larger display & some hardware updates, but older firmware, "2" about to release newer hardware & firmware but small display. Sure wish they'd combine efforts.

Greetings Alan,
You have proposed an idea on this subject that my old brain can almost understand! :)
I have a couple questions, if you care to elaborate. I will intersperse them below.

On Sun, Nov 17, 2019 at 08:20 PM, alan victor wrote:

Consider going through the effort of constructing a careful and well characterized "L matching" system, one where the L and C components are

Rather than constructing, would something like an inexpensive "QRP Antenna Tuner" be a useful accessory for the nano? It's just a stepped inductor and air-variable capacitor, with box and connectors, with a moderate impedance matching range.

Then this LC matching system can be taken to the antenna under test and simply use the VNA as an accurate high dynamic range reflectometer. You can readily tweak the match system to obtain a 40 or 50 dB return loss!

Understood. But I think a more typical use-case would be measuring at the end of the feed-line (typically low-loss open-wire parallel "ladder line"), as for high-Z non-resonant antennas, the feed-point impedance is rarely meaningful, and the transmission line impedance varies with length and frequency. I suppose one might measure it at the feed-point if the desire is to design a tuning stub or other Z-match device at the feed-point.

the LC match system now retains the information you desire, namely the Z of the antenna under test. If you take the network back to the shack and terminate the VNA port into 50 ohms, then the antenna port conjugate is the desired antenna Z. Now you could try to measure this Z with your VNA again, or have a calibrated L and C value already recorded on this little LC match system tool.

I'm not understanding how to connect and use the nano to determine the L and C values of this little L-network. I assumed one would need an LC meter for that.

Knowing the L and C values required to achieve the good return loss permits you to calculate the antenna Z.

My understanding of such things is acquired by practical "hands-on" examples (very limited in math skills). A practical example of determining the L-network's L and C, then converting those to Z would be very much appreciated!

Thanks! --kv5r

That's the LiIon battery protection circuit - don't touch it.It prevents the battery from being overcharged or discharging too much.Read up on battery protection circuits here:?

Hi all

Under the battery (3.7V - 450mAh) of my nanovna-H is taped a tiny pcb with 2 IC's, 2 resistors and a capacitor (all SMD), is there anyone who knows what this is ?

Jos

Op 18-11-2019 om 10:49 schreef DL8AAP:

[ann] : [NanoVNA] ~ [LabVNA] comparison using a 2-port

On Mon, Nov 18, 2019 at 08:22 AM, Dr. David Kirkby, Kirkby Microwave Ltd wrote:

"Is BH5HNU Hugen? I thought Hugen was working on nanoVNA-H, and BH5HNU on nanoVNA-F."

-------------------------------------------------------------------------------------------------------------------------------------------------

Dave,
Yes, Hugen's product is the 2.8" NanoVNA-H, and BH5HNU's is the 4.3" NanoVNA-F. BH5HNU has been so busy with orders and production that he hasn't had a chance to devote a lot of time to documentation and software development. Because the NanoVNA-F and NanoVNA-H have a lot of crossover, not only in how they operate, but in user's who own both models, ssome NanoVNA-F owners join the discussions on this board looking for information.

It leads to confusion at times because the NanoVNA-H's firmware is more advanced than the NanoVNA-F. The NanoVNA-F owner then begins to wonder why a feature described in the NanoVNA's operating manual isn't available on his device.

Herb

looks like edy555 has released version 0.5.0 as of the 17th...
.

Hi Conrad,

nice to meet you here so I guess I'm the 1. and you are the 2. 144MHz EME guy in the group :-)

I was lucky to buy 3 pieces of the -F version before he closed the shop but you may have read that his new shop is open soon.

Take care Conrad and always good deep decode.

73's Erwin/DK5EW

On Mon, 18 Nov 2019 at 15:52, Conrad, PA5Y <g0ruz@...> wrote:

Hello all, I was going to place an order for the NanoVNA-F today and the
link that I have for the BH5HNU version is down. I would like to buy from
a reputable source and I know that huygen is the developer. So can anybody
advise me where to buy the genuine article?

Regards

Conrad PA5Y

Is BH5HNU Hugen? I thought Hugen was working on nanoVNA-H, and BH5HNU on
nanoVNA-F.

Dave.

--

Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United
Kingdom

Forgot to attach the link:

Hope this helps
73
Greg/W4GAP

I got mine from Amazon. The reseller is Nooelec....

--
*73, Lucio I0LYL Rome, Italy*

Maybe here Conrad?



73, Drahos


Dne po 18. 11. 2019 16:52 u?ivatel Conrad, PA5Y <g0ruz@...> napsal: