QRP-Labs filter adapter for NanoVNA

This page is work in progress and will be updated frequently  :

wip_d2

This page is work in progress and will be updated frequently.

Introduction

I had a few QRP-labs lowpass filters and bandpass filters kits laying around and because I had nothing better to do this afternoon, I fired up the soldering station and assembled them. After that they need to be tested and tuned.

Owning a NanoVNA for a few months now (and hardly use it because for antenna stuff i use my RigExpert AA-600), I decided to use the NanoVNA for tuning the filters. So from some pieces out of my junkbox (a piece of double sided pcb, 2 sma chassis and a header cut in 2) I build this simple filter holder allowing me to test and tune the filters to my requirements.

nanovna_qrplabs_01

 First I drilled 5 holes for each side of the filter (the filter has 4 pins, but I need a via to connect the top and bottom layer) using a piece of perforated PCB. And with my Proxxon mini tool I mild a small track to the edge on both sides. 

nanovna_qrplabs_02

 Soldering the bottom side, the via (by using a piece of wire), the SMA chasis parts (edge side) and the headers.  

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 Soldering the topside of the PCB (the SMA chassis parts to the ground plane).

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All done, now its time  to do some testing.

Testing 

First I tested the newly build  15m lowpass filter.

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  Close-up 

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 Result looks good. -0.33 dB on 21Mhz. 

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Next I tested a 30m bandpass filter.  

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And after some tuning : -1.37dB on 9.93 Mhz.  

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Very happy with the result. 

Thinking about it and finding the ease for tuning, IMHO every QRP-Labs filter user (with out a spectrum analyzer with TG) should have one.  

  

Calibration  (Update 2020-04-07) 

When using the NanoVNA and change cables, adapters etc, you should calibrate it (mental note to my self).  

The popper calibration procedure is : 

  1. Got to the calibration menu by pressing CAL.
  2. Reset the current calibration state by pressing RESET 
  3. Enter the calibration menu by pressing CALIBRATE
  4. Connect OPEN standard to the CH0 port and press OPEN.
  5. Connect SHORT standard to the CH0 port and press SHORT.
  6. Connect the LOAD standard to the CH0 port en press LOAD.
  7. When you have 2 LOAD standards : connect a LOAD standard to CH0 and one to CH1 and press ISOLN.
  8. When you just have one LOAD standar : connect it to CH1 (leaving CH0 unconnected) and press ISOLN.
  9. Connect cables to the CH0 and CH1 ports, and connect the cables with a hrough adapter and press THRU
  10. End calibration by pressing DONE.
  11. Save it in a desired save slot by choosing SAVE - SAVE[0..4]

Experimental calibration tool 

Use at your own risk, I'm not a expert just a OM who does hamradio for the hobby. 

When you want to calibrate as close as posible to the adapter, you can't use the calibration standards. For that I made a simple calibration tool (it's good enough for HF).

 adapter_cal_01

adapter_cal_02

Note : the 2 via's to connect the both groundplanes aren't drilled yet. 

adapter_cal_03

On the right you see the 2 100 Ohm SMD 1206 resistors.

adapter_cal_04

The bottom view.  

Using this experimental calibration tool.

Connect the Adapter with 2 short SMA jumper cables to the NanoVNA.

Got to the calibration menu by pressing CAL.
Reset the current calibration state by pressing RESET 
Enter the calibration menu by pressing CALIBRATE

Don't connect anything to the adapter. 

adapter_cals_02

In the Calibration menu press OPEN.

adapter_cals_01

Place the calibration tool on the CH0 socket with the short (the side without the resistors).

adapter_cals_05

In the Calibration menu press SHORT.

adapter_cals_03

Place the calibration tool on the CH0 (adapter IN) socket with the load (the side with the resistors).

adapter_cals_06

In the Calibration menu press LOAD.

adapter_cals_04

 Place the calibration tool on the CH1 (adapter OUT) socket with the load (the side with the resistors).

adapter_cals_07

In the Calibration menu press ISOLN.

adapter_cals_08

 Place the calibration tool on the adapter with the pass through trace on the side of the SMA edge connectors.

adapter_cals_10

In the Calibration menu press THRU.

adapter_cals_09

End calibration by pressing DONE.

adapter_cals_11

Save it in a desired save slot by choosing SAVE - SAVE[0..4]

Now is the question : did it work ? 

It did a little. When I calibrated the NanoVNA with the supplied standards, the bandpass filter measurement had a peak of -0.83 dB.

adapter_cals_14

When I used the calibrated tool on the NanoVNA  the bandpass filter measurement had a peak of -0.56 dB.

adapter_cals_13

Which would indicate that the entire adapter configuration would cause -0.17 dB gain (or 0.17 dB attenuation).

But then again I'm not a expert just a OM who does hamradio for the hobby and does a lot of experimenting to get hands on experience with this matter.  

 
A nice PCB (Update 2020-04-06) 

Important note : the original PCB has got a upgrade, please continue reading and checkout the V2 design.. 

Knowing that not all people have tools to mill PCB's by hand, this morning I took time to create the schematic for the adapter in KiCad.

That way I could make a PCB design from it.

adapter_sch

adapter_pcb

The cool thing from KiCad is that is also has a 3D viewer. Unfortunatly the SMA Edge connectors aren't in the 3D shape library.

adapter_3d_layout

But it looks cool anyway. I also designed a small case which you can 3D print so you won't get shorts testing your filters.

I made the design publicly available so you print your own 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 3D design 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 want it to be used Commercial, please contact me.   

 

When the PCB design was ready, I have ordered a pack of 10 prototype PCB's at https://www.pcbway.com/ with slow delivery. During the order process you get a image rendered based on you gerber files how it would look in real-life..

adapter_layout

When I receive the prototypes I will check if they are OK (a small design error is easily made) and I keep 3 (2 for my self and one for the hamradio club) and the rest will be sold a cost price with a addition of a small fee as a token of appropriation / commission to support my work. On request even completely assembled with soldered headers, edge connectors and a 3D printed case. But remember to read this page first.

PCB's are in the house  (Update 2020-05-16)  

Today I received my long awaited package from PCBWay and I just had to assemble one adapter

nanovna_qrplabs_06

Bottom

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The 3D printed holder for the adapter PCB.

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And the test.

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Can only say one thing : it looks cool :-) 

For those who want a adapter, I have 7 spare PCB's in stock. Checkout my ForSale page. 
 

 
A updated PCB design V2 (Update 2020-05-27) 

In the QRP-Labs groups.io group it was suggested that build in calibration options would be handy. So I updated the design this afternoon. 

adapterv2_sch

It now has all the calibration stuff  you need onboard.  

 

adaptervw_pcb

And again it looks cool in the 3D viewer. Unfortunately the SMA Edge connectors aren't in the 3D shape library.

adapterv2_3d_layout

When the PCB design was ready, I ordered a pack of 3 prototype PCB's at OSHPark.com (more expansive, but faster delivery then https://www.pcbway.com/ ) with.

When I receive the prototypes I will check if they are OK (a small design error is easily made) and I keep 1 (one for my self and one for the hamradio club) and the other will be sold a cost price with a addition of a small fee as a token of appropriation / commission to support my work. On request even completely assembled with soldered headers, edge connectors and a 3D printed case. But remember to read this page first.  

OSHPark PCB's are in the house  (Update 2020-06-12)  

Today I received the 3 prototype PCB from OSHPark.com 

nanovna_qrplabs_06

and just like the previous batch I had to assemble one adapter.

First to install are the 4 100 ohm SMD resistors.

nanovna_qrplabs_06

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Adding the 3D printed base plate, hooking it with my NanoVNA.

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Doing the calibration routine.

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And ready for testing.

nanovna_qrplabs_06

As expected like the previous design. But now no additional PCB for calibration. 

nanovna_qrplabs_06

Can only say that the purple on yellow looks cool :-) 
 

A new version specially for the NanoVNA V2

A few owners of the new NanoVNA V2 have requested me if I could re-design the PCB so male SMA edge connectors can be used to directly connect the adapter PCB to the NanoVNA V2. The new NanoVNA V2 now uses through hole SMA female connectors which should give a constant distance between the S1 and S2 connector. All ready having intentions  to order the new NanoVNA V2 (because of the 3Ghz upper limit and some idea's about 13cm experiment), I ordered it and when it came in I measured the distance between the 2 connectors.

On my NanoVNA V2 the distance was 46mm and comments from other OM's indicate that it's quite constant +- 0.1mm. 

So I made a copy of the original design and changed the board layout to fit our needs. 

adapterv2_nanovna_v2_layout

I ordered little bigger than normal prototype batch at PCBWay.com (a few OM's all ready signed up for the new PCB) and after delay at customs (for unknown reason), the boards arrived. And of course I couldn't wait to assemble one. 

nanovna_qrplabs_37

A new base plate was designed and 3D printed. 

Again, I made the design publicly available so you print your own 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 3D design 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 want it to be used Commercial, please contact me.   

And every looks new and shiny. 

nanovna_qrplabs_43

Ready for some testing and after a short calibration cycle, it was showtime. 

nanovna_qrplabs_47

The 10m BPF responded as expected. 

nanovna_qrplabs_46

 

A new version specially for the NanoVNA H4

A few owners of the new NanoVNA H4 have requested me if I could re-design the PCB so male SMA edge connectors can be used to directly connect the adapter PCB to the NanoVNA H4.  For a while I holded it off, but recently I got my hands on a used NanoVNA H4 which I'm very happy with because of the bigger screen (yes my eyes aren't getting better). I started to use the H4 and wanted a dedicated adapter for it. So I measured  my NanoVNA H4 and it has a distance of  39.5mm and comments from other OM's indicate that it's quite constant +- 0.1mm. 

So I made a copy of the original design and changed the board layout to fit our needs. 

adapterh4_layout

I ordered little bigger than normal prototype batch and again after a delay at customs (for unknown reason), the boards arrived.

And again I couldn't wait to assemble one. 

nanovna_qrplabs_48

The PCB has a different size so I had to design a new base plate. 

Again, I made the design publicly available so you print your own 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 3D design 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 want it to be used Commercial, please contact me.   

And again it looks new and shiny. 

nanovna_qrplabs_52

Ready for some testing and after a short calibration cycle, it was showtime. 

nanovna_qrplabs_53

The 10m BPF responded as expected. 

nanovna_qrplabs_54

 

 

 

Where to buy

I ordered a large number of PCBs and sell these bare PCBs (physical and gerber files) through my website (check out the For-Sale page).

When you want a complete it and full assembled adapter, you can buy them through my webshop on Tindie

I sell on Tindie

Note : due to  terms of usage when selling on Tindie, the adapter kits and full assembled adapters can only be bought on Tindie. Bare PCBs and product which I don’t sell on Tindie can be bought through my website. And when you buy these adapters anywhere else, they are clones or rip-offs (it happened to be me before) and I can’t give any support or answer questions regarding these products.  

 

QRP-Labs filter adapter V2 for NanoVNA (V1, V2 and H4) Kit building and usage manual
 

I wrote a manual on the construction and how to use it. This manual can be download here : link to manual (PDF).

Note : I’m currently updating the original V2 design construction manual to include NanoVNA V2 specific parts steps and procedures. It will be online in a few days.

 

   


BOM (Bill Of Materials) 

A few people has asked me if I have a BOM for this adapter. I didn't but now we have :-) 

 

DigiKey
Amount Description DigiKey number DigiKey URL
2 Header female 4 pin 2057-RS1-04-G-ND link
4 SMD Resistor 1206 100 Ohm 311-10KERCT-ND link
2 Jumper S9341-ND link
6 Header male through hole 2 pin 732-5315-ND link
2 SMA Edge connector female 1.6mm CON-SMA-EDGE-S-ND link

 

When I have time I will compile a few list for other suppliers.

 

 

Some more photos

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nanovna_qrplabs_31

nanovna_qrplabs_34

 

Need some more inspiration ? Check out the Customer Gallery with pictures made by OM's who use this adapter. 

John KC9KKO who bought a digital license for 6 PCB's because several of his club have both NanoVNA and QCX’s. Replaced the female SMA connectors with male SMA connectors so the adapter could directly be used on the NanoVNA. The position of the connectors of the adapter and the NanoVNA don't excactly line up. So when I got my hands on two male SMA connectors I also build one like this. And a have to say that it works great. When you use the 3D printed base, you have to use a x acto knife to trim a little of one of the slots. 

nanovna_qrplabs_29

nanovna_qrplabs_30

Great idea John. Really love it.