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Having a really hard time imagining how you would "provisionally" attach the nanoVNA to the coax. I highly recommend getting an adapter or pig tail. I have purchased adapters and jumper cables from Amazon and it has been about 50/50 hit or miss on quality and being able to do the job. BNC connectors are particularly bad where I have had them not really mate well because of machining burrs and most don't connect the outer shield properly because the inside bore of the female is too large and/or the fingers on the male have no springiness and fail to contact the inner bore on the female - the shield/ground reins top only connecting through the bayonet pins, maybe OK for video, but not so much for RF.

I have had good luck with R and L Electronics in Ohio, where a UHF female to SMA male adapter is $3.95.

Also, if you test with the PL259 installed, you confirm the integrity of your soldering work and you are equipped to re-check the antenna at any time you have doubts or concerns.

Finally - If you have fun on CB, be sure to look into getting a ham licence, Technician isn't too hard and your options are much wider.

Adapters make it easy.

But at 27mhz, could use a couple 10cm long test leads
with alligator clips to somehow connect braid to braid
and center conductor to center conductor.
That would work just fine.

Jerry, KE7ER

On 10/5/20 8:12 AM, vitovsky.petr@... wrote:

Hello,
I ordered NanoVNA and it should arrive this week. I'm building wire dipole for my CB and I would like to measure its SWR. The problem is that I will be using the PL-259 connector and the NanoVNA I ordered has only SMA. The PL connector is not attached to the coax (RG-58) yet. Is it possible to measure the SWR just by attaching SMA to the coax

provisionally and replacing it with the PL when I'm done? Or do I have to buy SMA to PL adapter?

Get yourself some SMA to PL-259 adapters (actually, what you probably want is SMA to SO-239 jacks..

There's two ways to go about it.

a one piece adapter (I got a set of all 4 gender combinations for <$10 from amazon - )

A short cable with SMA on one end and PL-259 (I had one from my mobile rig installation a while ago, about 12" long).

if you go on amazon and search "SO-239 SMA pigtail" you'll get a bunch.. Looks like a pair of 6" ones is $10


I prefer the pigtail - cables with PL-259s tend to be fairly stiff, so having some inches of small diameter cable in between reduces the stress on the VNA.. you really, really do NOT want something like 0.405" coax directly connected to the VNA - you might snap the connector off the board.

Thanks for any advice, as a newbie I really appreciate it.

Hi Carol,

Thanks. I guess any capacitor can be used in order not to block the frequency or better said a capacitor which lets through my frequency of 174 MHz. Right ?

Just guessing :-)

Rainer

Either of those solutions will work fine.? The only caveat is to be careful not to break loose the connector on the nano.? At 27 MHz you don't need to be very careful about lead length and such.
I got an SMA-to-BNC adapter and do all my connecting from there.? I have various adapters and test leads so I can measure most things.? I measure capacitors, inductors, resistors, coax, antennas, you name it.? Very informative as you watch the changes vs frequency and all.
Bob

A schematic diagram posted a similar thread on Reddit shows there is a DC current path through resistors on the NanoVNA ports.
You can possibly damage the NanoVNA ports if you apply a DC voltage from the bias T to them. You need to attach a DC blocking capacitor in series with any connection to the NanoVNA on which a DC voltage is present.

Carol

On Mon, Oct 5, 2020 at 08:50 AM, OneOfEleven wrote:

On Tue, Sep 29, 2020 at 06:07 AM, Hugen wrote:
We have been working closely with Jan and provided all manufacturing support for Jan's second version of the VNA design. The results so far are very satisfactory, but we still need to make some final improvements. It isexpected that Jan can complete the final design of VNA2 in the next few weeks.

I'd certainly be interested in buying one when/if they become available.
==============================================================

I'm damping my enthusiasm until I see if the software support matches the hardware. Automation is important to me and I have yet to see any information in that respect. Ideally a console command interface that is backwards compatible with hugen's other family of product's (excluding the V2), or a higher level VISA command interface would work.

The tinySA is a great example of launching a hardware project that capitalizes on backwards compatibility with an existing product (NanoVNA) for software support.

- Herb

On Tue, Sep 29, 2020 at 06:07 AM, Hugen wrote:

We have been working closely with Jan and provided all manufacturing support
for Jan's second version of the VNA design. The results so far are very
satisfactory, but we still need to make some final improvements. It is
expected that Jan can complete the final design of VNA2 in the next few weeks.

I'd certainly be interested in buying one when/if they become available.

Hello,
I ordered NanoVNA and it should arrive this week. I'm building wire dipole for my CB and I would like to measure its SWR. The problem is that I will be using the PL-259 connector and the NanoVNA I ordered has only SMA. The PL connector is not attached to the coax (RG-58) yet. Is it possible to measure the SWR just by attaching SMA to the coax provisionally and replacing it with the PL when I'm done? Or do I have to buy SMA to PL adapter?

Thanks for any advice, as a newbie I really appreciate it.

Hi,

One more question in regard to my Set up.

It is a DIY 4 element YAGI antenna for the frequency of 174 310 000 Hz and the LNA is Bias Tee powered from the connected RTL-SDR receiver.

Is there a way to measure something putting the Nano VAN in through operation or will I damage my Nano VNA when I power my LNA via Bias Tee from my RTL-SDR device ?

Maybe a dumb question and perhaps nonsense but as I said I am total Newbie and want to learn.

Thanks for your patience.

Rainer

Hi Ignacio,

Thank you very much.

Will do. As I have build a second antenna with the same characteristics as the one which is working I can measure the one which is not installed on the roof and so know if I am on the right track.

regards Rainer

Hi Carol,

Thank you very much. I will have to dismantle everything then. :-)

regards Rainer

You save your test setup exactly the same way you save your calibration - in the same memory slot.
Do your cal for the freq span you want to test in and save to slot 2 (for example). Slot 0 is reserved for power-on recall.
Next, set up the nano for your test and when it is configured the way you want, go and save again back to slot 2.
As long as you didn't change the freq span, slot 2 will now be recalled the way you want for your testing.

Hi, is there a way to save one's test settings? I know you can save calibrations in 5 places, but what about the settings for a particular test?

Good evening Gyula,

Thank you for the reply and information, very much appreciated.

Regards 73’s

Gary
VK4OO

Hi Chris,
Since the creator of NanoVNA Partner does not have his own website, I offered to store the file at the time of creation. So it can also be found in my storage (.rar and .zip) format, as there were those who had difficulty unpacking the .rar format.
The program can also be used on windows XP, according to the published description.
I guess anyone who has an early computer and hasn’t thrown it out, its use shouldn’t be a problem.




73, Gyula HA3HZ
--
*** If you are not part of the solution, then you are the problem. ( ) ***

Yes, if you wish to measure the characteristics of the antenna.
No, if you wish to measure the characteristic of the amplifier.

Carol

If I understand it correctly, you have a LNA connected to the antenna and the cable connected to the output goes to your shack and you want to measure from there, right?

In that case you will measure LNA output impedance and so, and nothing related to the antenna. You need to bypass the LNA in order to measure the antenna, and you better calibrate the nanoVNA accounting for the cable, so you have to connect the Open, Shot and Load calibration standards where the cable is connected to the antenna. Or you can calibrate with just the pigtails and then connect them directly to the antenna.

Regards,

Ignacio, EB4APL

--
El software de antivirus Avast ha analizado este correo electrónico en busca de virus.

Hi,

Started this new hobby setting up a RMO station and now I want to measure my DIY 4 element Yagi antenna in roder to optimize it.

Is it possible to measure the antenna leaving a Low Noise Amplifier in the circuit or do I ahve to remove it ?

Thanks in advance for any tips

regards Rainer

Hi,

Just entered this interesting hobby of Radio SDR for RMO, DIY Antennas and all that stuff.

Got my Nano VNA H today and I have a question. Do I need tot ake off my Low Noise Amplifier for measuring my DIY antenna ?

Thanks in advance for all tips.

regards Rainer