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Connectors on RF Test Board leads

Christopher Pettitt
 

I have just tried to use the RF Demo Test board I purchased with my NanoVNA. I find it impossible to connect the leads supplied to the tiny connectors on the test board. I assume I am not alone having discovered this problem. The RF Demo Test board is a wonderful idea but not much use if you can't connect to it.
Regards
Chris G0EYO
 

I bought one also and I cannot connect the cables either.

Nice concept, but if it doesn't work, what good is it.

Caveat Emptor

73, Dick, W1KSZ
________________________________
From: [email protected] <[email protected]> on behalf of Christopher Pettitt via Groups.Io <g0eyo@...>
Sent: Thursday, January 16, 2020 7:11 AM
To: [email protected] <[email protected]>
Subject: [nanovna-users] Connectors on RF Test Board leads

I have just tried to use the RF Demo Test board I purchased with my NanoVNA. I find it impossible to connect the leads supplied to the tiny connectors on the test board. I assume I am not alone having discovered this problem. The RF Demo Test board is a wonderful idea but not much use if you can't connect to it.
Regards
Chris G0EYO
[email protected]
 

Yes, those cheap U.FL plugs are a challenge to seat. I use SMA to U.FL adapters. Example is from Centric RF C9917B - Adapter U.FL/Plug S<A-Female (U.FL/AMC compatible) S Steel 6GHz VSWR 1.3 The adapters easily and reliably connect.
Regards,
John N9JSA
 

Just be aware that the connectors used on the board are not made for repeated connect/disconnect and will not stand up to repeated connect/disconnect. Cables need soldering to prevent breakage .
 

You need a slit screw driver about 5 mm wide.
Hold with one hand the female connector of the cable centric over the male plug on the board,
and press with the other hand the female plug with the screw driver down, parallel with the board.
The first time you connect it needs some force, but the next connections are easier.

To open the connection use a 1 mm wide slit screw driver.
With one hand hold the cable at the connector down,
with the other hand lift with the screw driver the connecter at the crimping position up.

It works, but needs some learning.

To make U/FL cable female connector foolproof, solder the middle crimping,
see the picture at

73, Rudi DL5FA
 

I concur with these statements though I have managed to get the connectors
mated but with some great effort and care.
*Clyde K. Spencer*

On Thu, Jan 16, 2020 at 10:20 AM Dick <w1ksz@...> wrote:

I bought one also and I cannot connect the cables either.

Nice concept, but if it doesn't work, what good is it.

Caveat Emptor

73, Dick, W1KSZ
________________________________
From: [email protected] <[email protected]> on behalf of
Christopher Pettitt via Groups.Io <g0eyo@...>
Sent: Thursday, January 16, 2020 7:11 AM
To: [email protected] <[email protected]>
Subject: [nanovna-users] Connectors on RF Test Board leads

I have just tried to use the RF Demo Test board I purchased with my
NanoVNA. I find it impossible to connect the leads supplied to the tiny
connectors on the test board. I assume I am not alone having discovered
this problem. The RF Demo Test board is a wonderful idea but not much use
if you can't connect to it.
Regards
Chris G0EYO
 

Another problem with the demo board U.FL connectors is that they are surface mounted and unless you physically hold the connectors down while disconnecting cables can easily detach from the board. This happened to me while I was demonstrating the board at my ham club. Needless to say there were not many interested buyer's after seeing that. I also had to physically hold down the test cables during sweeps to maintain a good connection.

As other members have said, the demo board is a good concept but poorly implemented with the U.FL connectors. The demo board went into my bottom desk drawer with all the other Asian electronic devices that didn't live up to their billing. If I had seen reviews like the recent ones on this board before my purchase, I would have went with the sdr-kits demo board.

- Herb
 

I agree, they're very difficult to connect and disconnect. Here's an outlandish idea I considered...Amazon has U.FL to panel female SMA connector jumpers in lengths up to 12 inches. IF someone REALLY wanted to have a permanent fixture you could get one for each demo section and build yourself a complete demo box; that way you'd only have to connect them up once and could then tap into whichever of them you wanted to. Guess you'd have to characterize the jumpers as well...but I digress. Yep, it sounds ridiculous I agree and did I say expensive? They're around $12 for four jumpers...you do the math since you could buy a couple more nanoVNAs for the money you'd invest in such a project...but it would work. 73 - Dino KL0S
 

A cheaper solution would be to take a board mount female SMA connector,
solder a strip of 3 header pin sockets to it instead of a PC board.
Then clip up a pin header strip into sections of 3 pins to mate with the sockets,
and add a selection of junkbox resistors and coils and caps and crystals to each.

Total cost of about $5. No U-FL connectors to break. No $40 demo board.
If you keep everything down under 100mhz, no need for 10ghz connectors.
The only thing that's going to wear out is the 3 header pin sockets,
which are easy to replace for pennies.

Jerry, KE7ER

On Fri, Jan 17, 2020 at 06:41 AM, Dino Papas wrote:


I agree, they're very difficult to connect and disconnect. Here's an
outlandish idea I considered...Amazon has U.FL to panel female SMA connector
jumpers in lengths up to 12 inches. IF someone REALLY wanted to have a
permanent fixture you could get one for each demo section and build yourself a
complete demo box; that way you'd only have to connect them up once and could
then tap into whichever of them you wanted to. Guess you'd have to
characterize the jumpers as well...but I digress. Yep, it sounds ridiculous I
agree and did I say expensive? They're around $12 for four jumpers...you do
the math since you could buy a couple more nanoVNAs for the money you'd invest
in such a project...but it would work. 73 - Dino KL0S
 

I think the vendor really needs to supply a larger PC board with PC mount
SMA female connectors. The larger PC board would even be better for
presentations as it could be more easily seen, The SMA connectors would be
more robust and provide easy connections.

*Clyde K. Spencer*

On Fri, Jan 17, 2020 at 9:41 AM Dino Papas <kl0s@...> wrote:

I agree, they're very difficult to connect and disconnect. Here's an
outlandish idea I considered...Amazon has U.FL to panel female SMA
connector jumpers in lengths up to 12 inches. IF someone REALLY wanted to
have a permanent fixture you could get one for each demo section and build
yourself a complete demo box; that way you'd only have to connect them up
once and could then tap into whichever of them you wanted to. Guess you'd
have to characterize the jumpers as well...but I digress. Yep, it sounds
ridiculous I agree and did I say expensive? They're around $12 for four
jumpers...you do the math since you could buy a couple more nanoVNAs for
the money you'd invest in such a project...but it would work. 73 - Dino
KL0S
 

A larger test/ demo board with SMA connectors would also allow component values to be included in the silk screen printing, without readable values I feel? the demo capability is reduced.

John Knott 2E0KNJ
 

All you need



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

test.jpg

 

IF you need a little more flexible test board, take a look on SDR-Kits :

Not all software functions of the DG8SAQ software can be used, but the supplied experiments can also be done with a NANO-VNA. The Training slides needs some basic RF knowledge to follow: it is not fully "entry level". So I would recommend a look into the slides and the assembly instruction before ordering.

There is no need to go to high frequencies (>100MHz) to understand the functionality of an VNA. The standard measurement functions and limitations get already visible on the lower frequencies.

vy73 de Karsten, DD1KT

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