Component Measuring Adapter for QRP-Labs filter adapter


This page is work in progress and may be updated frequently (last update : 2022-09-30). 


As a hamradio homebrewer I often use my NanoVNA to measure filters, antennas and crystals. But a NanoVNA is much more than that, you can also measure components with it. For that I  use a improvised adapter which plugs into my QRP-Labs filter adapter for NanoVNA.

A small strip of PCB is cut to the size of a QRP-Labs adapter PCB, the copper on one side is separated in half and one half is separated again in the middle. A small piece of experiment PCB with holes is used as a template to drill the 16 holes for the female headers.

To connect various sizes of components, it contains of a 2x4 female header connected to ground, a 2x2 female header connected to CH0 / IN and a 2x2 female header connected to CH1 / OUT. 


Top and bottom are connected to ground (note the IN and OUT section are cut free from the ground plane.


And it fits perfect to my QRP-Labs filter adapter for NanoVNA

Note : the PCB is place wrong here) 





From the schematic above I designed a PCB which could fit into the QRP-Labs filter socket. I ordered a batch and when the PCB's arrived I collected the parts and documented the build process.

When all works out well, the left over PCB's will be sold bare, as a kit or on request build and tested (see note below). 


Lets start building

I used my QRP-Labs filter adapter for NanoVNA as a soldering jig. 

Step 1 : place the 4 pin headers in the 4 pin female headers.


 Step 2 : place the PCB on the headers (OUT = left, IN = right) as shown below.


Step 3 : solder both 4 pin headers


 Step 4 : Place the female headers on the PCB.


Step 5 : While holding the components take the PCB out of the adapter and place it on the table/soldering pad/etc.


Step 6 : Solder one side of the headers (one pin on each header). 


Step 7 : Turn the PCB over and check if the headers are nicely placed (if not, correct them).


Step 8 : Solder the rest of the header pins.


Step 9 : place filter on the adapter, sit down, relax and enjoy the fruits of you labor. 


Lets taste the pudding aka get some measurements done.

Step 1 : Calibrate your NanoVNA for a span of 100KHz to 10 MHz. 

Step 2 : setup you NanoVNA to show R + L/C on S21 (I use a Dislord firmware on my NanoVNA, so for you NanoVNA it may be different of not needed at all).

Step 3 : Take a small piece of wire and make a 10 turn small coil over a 5mm drill aprx 10mm width.

Step 4 : Place the coil between IN and GND. The result should similar like this. My coil has a Inductance of aprx 340nH.


I then measured the coil on my DER-EE DE-5000 LCR meter at 100 KHz. 



It works like a charm.

Where to buy 

The left-over PCB's of this small batch will be sold through the For-Sale page on my website. When they are sold out and there is a demand, I might be ordering a new batch of PCB's to sell them, make new kits or even sell full assembled filters. So when they are sold out and your interested, let me know.   

The design will be publicly available (use the For-Sale page  to request GERBER files) so you order your own PCB's at OSHPark or a other PCB factory of your choice, but licensed it Attribution-NonCommercial-NoDerivs 3.0 Unported (CC BY-NC-ND 3.0).
Meaning : 

  • Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
  • NonCommercial — You may not use the material for commercial purposes.
  • NoDerivatives — If you remix, transform, or build upon the material, you may not distribute the modified material.

It's not to be childish but it now happened a few times that a  designs I made was sold by other people just because is was "Open source, so I can do anything I want with it" without any credits or even a token of appreciation

When you like the design and PCB's. a small fee as a token of appreciation / commission to support my work is very appreciated (see : Support & Tip Jar).

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