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Hello Roger, Since some customers want to DIY their own cases and add larger batteries, we still offer the NanoVNA-H with sandwich construction（Just like my earliest handmade ones）. Out of customer demand for the rev3.4 version, we post the same label on the package as the ABS shell version. If the internal PCB is consistent with what I posted on GitHub, it should be made by us. If the user is not a avid DIYer, I still recommend them to purchase the ABS shell and "gift box" version. The buttons and screen with the ABS shell and "gift box" version are effectively protected and more suitable for daily use.

hugen

I just saw this posted in the NanoVNA Facebook group. It supposedly is a NanoVNA-H version 3.4. The label looks like a 3.4 version but it is not in the "gift box" with the gold lettering. Seems to be missing a cable and the stylus pick. Is it a genuine Hugen or a copy of his PCB and circuit changes.?

The 3.2" display I ordered for my S-A-A-2 arrived today (see attachment). It took all of about 5 minutes to unscrew the old 2.8" display, remove it from the 14-pin socket and plug the 3.2" display in.

Observations:

1. Visually there is not a big difference between 2.8" and 3.2" display modules. If the firmware driver for the 3.2" display used hugen's AA character set, the change would be more worthwhile.

2. The mainboard mounting holes for the 3.2" display module do not line up with the mounting holes for the 2.8" module, so you have to improvise a way of securing the 3.2" module to the mainboard, other than the 14-pin socket. This will be an even bigger problem for a 4" display module since the module will dwarf the mainboard itself.

3. The 3.2" display module makes a great spare for the original 2.8" display module and has a SDCard module on the rear which may receive future firmware support through the 14-pin socket.

- Herb

The older versions of the NanoVNA-H used a 3.7 V 450 maH battery LiPo battery (602040) and the latest version with the Version 3.4 board uses a 650 maH battery (602540). You can find them on Amazon & eBay and some radio control airplane shops carry them. The connector used is a JST type. Here are some photos..

is the NanoVNA-H

The battery size depends on which model you purchased. NanoVna, NanoVNA-H, NanoVNA-H4 or NanoVNA-F.

You can get up and running by plugging a 5V USB power pack into the USB socket on the NanoVNA.

Roger

I didnt realized that I purchased a NanoVNA without battery :(

What battery can I buy to put on it?

I appreciate the help.

On Tue, Apr 28, 2020 at 03:24 PM, WB2UAQ wrote:

... I use my Nanonvna with an HP 8721A directional coupler. ...
===============================
The HP 8721A bridge is hard to find on the secondary markets, especially the 50 ohm ones. I've had offers for mine that were hard to resist but I turned down. You should write up an application note for the group on using an external directional coupler to measure return loss and impedance, with accompanying math. I believed one of our members at one time asked Rune if he would add a module to NanoVNA-Saver for measuring return loss and impedance using an external coupler.

- Herb

I use my Nanonvna with an HP 8721A directional coupler. As noted above attach ch0 to the input of the coupler and ch1 to the reflected port of the coupler. Attach a short to the directional coupler's output port and do a through cal with the short in place. S21 is now the return loss of what is connected to the coupler's output. Because the Nanovna also outputs S21 phase you can calculate the impedance of what is connected to the coupler's output port. The HP 8721A has a directivity spec of 44 dB from 100 kHz or so to 110 MHz. I have verified this with an HP cal kit load. This method might even be more accurate than using Ch0 making an S11 measurement. If you don't have a good commercial coupler, a very good one can be made. All it takes is some wire and a pair of ferrite toroids. Look up the Stockton coupler on the web.

Thanks all.

Herb, you got me in the right direction I am sur I will be able to figure
this with the link you provided.



<>
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sans virus. www.avast.com
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Greetings Erik,

Congratulations on your handheld SA project! I imagine it will become a very popular product.

I have decades of experience with RF instrumentation and a background in telecommunications engineering standards and design. I own a Tektronix 7L13 spectrum analyzer, HP 8656B RF Generator plus a Signal Hound spectrum analyzer/tracking generator pair. I have written articles regarding my DDS designs for Circuit Cellar and ARRL QEX magazines. I had the good fortune to be in the winning circles of a couple of microcontroller design contests regarding my DDS RF generator projects. Recently I designed a simplistic but inexpensive step attenuator to provide a front end for adapting a popular SDR receiver module to function as a broad coverage spectrum analyzer. The relative portability of your stand alone design that does not require a host PC appeals to me.

Should you select me it would be my pleasure to evaluate your analyzer design and provide you with test results.

--
Best Regards,
Tom, VA7TA
tma.7ta_at_gmail.com

Pierre,
A good illustrated guide for such measurements is at:



Just substitute the NanoVNA CH0 for the signal generator and the NanoVNA CH1 for the spectrum analyzer in the article. The directivity measurements will be S21 in dB.

- Herb

Herb,

You are very right.

To all the people posting about using the tinySA to tune filters and antenna. This is not the intended use case as you need to combine two tinySA to have the tracking generator option and currently the dynamic range is insufficient (due to IF leakage, to be solved) for tuning the stop band of filters. And there is no bridge in the tinySA so you can not measure antenna

For tuning filters and antenna better use a nanoVNA!

--
NanoVNA Wiki: /g/nanovna-users/wiki/home
NanoVNA Files: /g/nanovna-users/files
Erik, PD0EK

Members responding to Erik's tinySA post should note that he asked, " If you think you could contribute to the testing feel free to send me a PM with some info on the project you'd like the tinySA for." PM means private message.

If you don't want to send a private message then you should post your response on the group Erik has set up for the tinySA, /g/tinysa/topics so the NanoVNA group doesn't get flooded with tinySA related me too messages.

Regards,

- Herb

Use 290-310MHz range in high step - very hard mode for si5351 (therefore, I suggested using it to determine stability) try reduce threshold value to 299MHz or less and save, possibly it help)

PS strange i always calibrate vs 50OHm load on CH1 (but do it standalone).

PSS Try to clean the board in the area of the RF connectors, and under the metall screens) using alcohol, also cleanup calibration standarts and inside. Possibly broken cable.

Poke around in "RFCafe.com".

Yes, one can use the NANOVNA's to determine the parameters of directional
couplers. However, describing the setup for each parameter would be a bit
long and maybe a bit ambiguous in just verbiage. Diagrams are really
needed to do the description justice and clarity.

"Microwaves101.com" might also offer some good information.

Dave - W?LEV

On Tue, Apr 28, 2020 at 10:45 AM Dragan Milivojevic <d.milivojevic@...>
wrote:

Termination depends on the design of the coupler, some like "tandem match"
or stripline require termination
into their designed impedance, others like "douma bridge" and similar
don't.

The connections to the VNA depend on that you want to measure and that is
up to you.

On Tue, 28 Apr 2020 at 18:15, Pierre Martel <petem001@...> wrote:

Anyone have some idea if it is possible to test a directional coupler
function. Like how much signal is coupled out on fwd or rev with is the

max

bandwidth it can be used on and what would be needed as connection to

each

port. I am pretty sure a variable load at the out port should be there to
simulate miss match but would it need a 50 ohm load at the un tested

port?

(Fwd/rev) where should s0 and s1 plunged to? The input of the coupler or

to

the sampling port?

Thanks

Pretty new with vna and learning a lot

Pierre
Ve2pf

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

Termination depends on the design of the coupler, some like "tandem match"
or stripline require termination
into their designed impedance, others like "douma bridge" and similar
don't.

The connections to the VNA depend on that you want to measure and that is
up to you.

I tune many reject (notch) and band pass/band reject (BPBR) duplexers using a fairly large HP spectrum analyzer with tracking generator in 450-512MHZ band. It is almost impossible to to haul the unit up to a remote site, so a smaller portable unit would be welcome. It has about -80db dynamic range.

Anyone have some idea if it is possible to test a directional coupler function. Like how much signal is coupled out on fwd or rev with is the max bandwidth it can be used on and what would be needed as connection to each port. I am pretty sure a variable load at the out port should be there to simulate miss match but would it need a 50 ohm load at the un tested port? (Fwd/rev) where should s0 and s1 plunged to? The input of the coupler or to the sampling port?

Thanks

Pretty new with vna and learning a lot

Pierre
Ve2pf

I'd be interested in helping test, I have a pair of 20ghz antennas I am restoring that I could use more test tools for.
Thanks,
Michael AE1TE