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Look on wish.com. I picked up some from them and quite happy with it. Just
search for rf coax

On Wed, Sep 21, 2022, 5:42 PM Radu Bogdan Dicher <vondicher@...>
wrote:

Hi all,
Can anyone please help identify the type of coax the original kit SMA
cables are using?

I like the convenience of how skinny and flexible these cables are. I hate
thick, rigid cables, that make everything difficult, add bulk, and move
instrumentation from wherever it is to their most convenient bend radius.
I'd like to add some more SMA cables to my bench and not sure what to look
for.

Thank you!
Radu.

Use DISPLAY->FORMAT .... ->SMITH (need select it) and on next click SMITH need select value format

Hi,

I just upgraded to the newest version. It's DiSlord's 1.2.14.
I recognized, that the smith chart marker now displays the impedanze (R +/-jX) and not the value of C or L in pF or nH.
Is there a setting, to get back the value of the capacity or inductivity?

Thanks in advance!

Uwe

RG316 50 ohm coax
*Clyde K. Spencer*



On Wed, Sep 21, 2022 at 8:42 PM Radu Bogdan Dicher <vondicher@...>
wrote:

Hi all,
Can anyone please help identify the type of coax the original kit SMA
cables are using?

I like the convenience of how skinny and flexible these cables are. I hate
thick, rigid cables, that make everything difficult, add bulk, and move
instrumentation from wherever it is to their most convenient bend radius.
I'd like to add some more SMA cables to my bench and not sure what to look
for.

Thank you!
Radu.

On 22/09/2022 01:42, Radu Bogdan Dicher wrote:

Hi all,
Can anyone please help identify the type of coax the original kit SMA cables are using?

I like the convenience of how skinny and flexible these cables are. I hate thick, rigid cables, that make everything difficult, add bulk, and move instrumentation from wherever it is to their most convenient bend radius. I'd like to add some more SMA cables to my bench and not sure what to look for.

Thank you!
Radu.

You can buy ready-made SMA cables from Amazon and AliExpress (or similar).

For example:



There are PTFE variants:


Two things to watch out for:
- when using cables, calibrate with the cables in place for best accuracy.
- be sure not to buy "SMA-RP" cables. These have the male/female pins/socket
reversed. RP is reverse polarity:



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

?n joi, 22 sept. 2022 la 03:43, Radu Bogdan Dicher <vondicher@...> a
scris:

I believe it's RG 316/u
Bob VE3AMW

________________________________
From: [email protected] <[email protected]> on behalf of Radu Bogdan Dicher <vondicher@...>
Sent: September 21, 8:42 PM
To: [email protected] <[email protected]>
Subject: [nanovna-users] SMA coax cables the kit came with -

Hi all,
Can anyone please help identify the type of coax the original kit SMA cables are using?

I like the convenience of how skinny and flexible these cables are. I hate thick, rigid cables, that make everything difficult, add bulk, and move instrumentation from wherever it is to their most convenient bend radius. I'd like to add some more SMA cables to my bench and not sure what to look for.

Thank you!
Radu.

Looks a lot like RG-316/U

Hi all,
Can anyone please help identify the type of coax the original kit SMA cables are using?

I like the convenience of how skinny and flexible these cables are. I hate thick, rigid cables, that make everything difficult, add bulk, and move instrumentation from wherever it is to their most convenient bend radius. I'd like to add some more SMA cables to my bench and not sure what to look for.

Thank you!
Radu.

I had mine "lock up" . I removed the cover, disconnected the battery, and measured VCC and found it to hold a small voltage. I shorted to GND, reconnected battery and it came back to life. I hope this helps.

that's the problem, i cannot get an image to load onto it. i cant even get the computer to get the correct driver for it.

i have tried two different windows 10 21H2 machines that both show STM32 Bootloader in the device manager under USB Devices but the DFuse.exe tool will not show it as being connected in DFU mode.

On Mon, Sep 19, 2022 at 07:12 PM, Eric KO4ZEK wrote:

My NanoVNA-H4 is stuck in DFU mode. when i try to use the DFuse.exe it does
not see the device connected to the computer. when i go into device management
i see the STM32 Bootloader listed under USB devices. i have tried several
different articles on getting the windows 10 driver installed but nothing
seems to work.

thanks in advance

If the device is in dfu mode, install the firmware you want to use.
When that's done you turn it off and on and it should work.

The device will remain in dfu mode until you upload usable and working firmware to it.
--
Gyula HA3HZ ( )

On Mon, Sep 19, 2022 at 11:38 AM, Gerard wrote:

May you revalidate and write the correct procedure
thank you

You need to build a proper test jig when you test components. Stray inductance and capacitance will affect your results. For S21 measurements I use a test board like the one below. You can buy NanoVNA test boards (see wiki and other posts for details or build your own from scrap PCB material and SMA connectors.

Use the SOL loads by placing them in the fixture as shown. The 50 ohm isolation load is on the right side. When doing the through remove all loads and put a jumper across the device-under-test (DUT) position. After the through calibration and results saved you will see that S21 is 0 dB across the frequency range. S11 will not be of any interest because the series resistors are in place. Remove the jumper and put the MCF in place (remember to ground one lead)

Hope this helps you - Roger

Hello,

The filter is given as equivalent to a 45M15A.
The characteristics give a termination of 4Kohm and 2.5 PF.

I also found a more traditional test method to see.


On this site, you will see that an another testing with transformers as soon as the impedance of the filter is greater than 1Kohm


With the nanovna, I never managed to have a nice curve with my test model. Best with a -8DB dip between the peaks. I played on the values of resistors and capacitors without doing better.

I doubt that sentence: Set the trace to display LOGMAG and PHASE of the passing signal (CH1=THRU).
LOGMAG = S21 ?

also i doudt that sentence: Remove the crystal filter and connect the resistors to
get the through characteristics. Next, remove the connection between the resistors,
take the isolation characteristics, and CAL DONE in that state

so i doudt my calibration.
Short an open -->ok
load ? only 50ohm, or the two serial resistors, or 50 + serial resistor????
Throught --> only the 2 resistors
Isolate --> no thing connected.?
I’m not used to using the nano yet, so I doubt

May you revalidate and write the correct procedure
thank you

cdt

Another method used by Epson to measure MCF devices is to use matching transformers to perform the 50 ohm to Zt transformation.


This requires considerably more effort than the series method but the advantage is that you retain the S21 measurement range and can measure stop band attenuation to a greater depth. The trick is to get a good matching transformer for the MCF filter frequency. I suggest that binocular core ferrites be used because they require fewer turns and have a high coupling coefficient which means less leakage inductance and a better match. They come in different mixes so you can select the one suitable for the MCF frequency of operation.

Roger

On Mon, Sep 19, 2022 at 02:28 AM, Gerard wrote:

Hello, Good morning,

Very interesting article. I did a translation in French.
Now tell me if I’m wrong about the measurement method.
1) We calibrate the NanoVna and then we measure the filter, we obtain a raw
state of the filter (2 peaks).
2) The right measure would therefore be to calibrate the NanoVna with the 2
resistances in series (In our example 940 ohm --> 2*470 ohm) and not 50 ohms
3) Measure next.
4) Observe the curve

Similarly, I did not find the NDK 21F15B filter features to check if the
manufacturer impedance is around 470 ohm for our example.
I understood that in our case, it would take 2 adjustable resistors, and
repeat the operation to find the ideal curve.

Yes you have the correct procedure. Below is the test setup used by a Monolithic Crystal Filter (MCF) vendor using series resistors and a shunt capacitor to get the required termination impedance..



Note that if the MCF termination resistance is 520 ohms the series resistor would be 470 ohms (if the test equipment is 50 ohms). When you calibrate with the series resistors connected together the S21 measurement range of the NanoVNA will be reduced. Assuming a 70 dB range for S21 with a NanoVNA and using two 470 ohm resistors in series the S21 range will be reduced by 20 dB so you can only see MCF attenuation to 50 dB. The larger the resistors the worse it gets. With a termination resistance of 2000 ohms the series resistors would add up to 3900 ohms and the S21 measurement range will be reduced by 32 dB.

Roger

My NanoVNA-H4 is stuck in DFU mode. when i try to use the DFuse.exe it does not see the device connected to the computer. when i go into device management i see the STM32 Bootloader listed under USB devices. i have tried several different articles on getting the windows 10 driver installed but nothing seems to work.

thanks in advance

Eric W.

Hello, Good morning,

Very interesting article. I did a translation in French.
Now tell me if I’m wrong about the measurement method.
1) We calibrate the NanoVna and then we measure the filter, we obtain a raw state of the filter (2 peaks).
2) The right measure would therefore be to calibrate the NanoVna with the 2 resistances in series (In our example 940 ohm --> 2*470 ohm) and not 50 ohms
3) Measure next.
4) Observe the curve

Similarly, I did not find the NDK 21F15B filter features to check if the manufacturer impedance is around 470 ohm for our example.
I understood that in our case, it would take 2 adjustable resistors, and repeat the operation to find the ideal curve.

am i right?
cdt

Roger,
You are correct that it does not change the actual impedance presented to the filter.
However, it is possible to mathematically compute S parameters in, say, a 500 ohm system knowing the S parameters in a 50 ohm system, at least for a passive DUT.
A full set, S11, S12, S21, and S22 is ideally need, but for most passive devices(isolators excepted) S12=S21, and for a symmetrical device like many filters, S22 is approximately equal to S11.
The latest DisLord and earlier ojisankoubou NanoVNA-V2 firmware does this calculation. It does work.
--John Gord

Edy555, the first NanoVNA developer, did some measurements on monolithic crystal filters like the ones Gerard is using (45R15AZ; motorola 20J26) . The article is on his website in Japanese at the link below:



A translation to English is attached.

Roger