1206 Attenuator PCB


This page is work in progress and may be updated frequently (last update : 2020-07-30 10:37 UTC). 

This is a updated design of the previous 1206 Attenuator PCB (aka a failure in PCB design).


As a hamradio homebrewer I often use attenuators to get a signal down a few dB and sometimes I want very strange values. For those cases I designed these 1206 PI network Attenuator PCB's with SMA Edge connectors using KiCad. 


Based on this schematic I designed the PCB shown below. I added area's without solder mask around the edges to a low adding some shielding over the PCB (not visible in image below).


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


For the attenuation values I used this calculator : https://chemandy.com/calculators/matching-pi-attenuator-calculator.htm and  the image below contains a list of "standard" PI network attenuation resistor values. 


It's nice to have it all in theory but we want the real thing. So I ordered small batch of pototype PCB's to see if I didn't mess up this simple design. 


Let's test them/

When the "small" batch of PCBs came in (ok, I orded a little more then I needed, but like to fill up my webshop ;-) 



I couldn't resist building 2. One  0dB and one 10dB.


and put them to the test using my NanoVNA H4 (to later find out that i configured 1.2GHz instead of 1.5GHz). :-S 

Test setup : NanoVNA H4 with 2 x 20cm test leads, frequency span 1MHz to 1.2GHz.

0dB Attenuator PCB @ 600MHz.


10dB Attenuator PCB @ 600MHz.


10dB Attenuator PCB @ 1179MHz 



Test setup : NanoVNA H4 with 2 x 20cm test leads, frequency span 1MHz to 450MHz.

0dB Attenuator PCB @ 225MHz 


0dB Attenuator PCB @ 450MHz 


10dB Attenuator PCB @ 225MHz 


 10dB Attenuator PCB @ 450MHz 


Conclusion : 

Much better the the previous version and one for the keeping for atleast up to 1.2GHz. 


Where to buy 

From the not so small batch of PCBs I have a "few" left. When you interested use the form on the For-Sale page.

The design is publicly available (use  For-Sale page to request GERBER files) so you order your own PCB's at OSHPark 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).


User Gallery

When people buy one of my PCB's, kits etc. I ask then if they send me a picture when they build it or using it. Below you find images some OM's send me.
OM's thanks for the pictures. All pictures (c) to the OM. 

Jean-Paul PF0X

When Jean-Paul PF0X received his package and he build them, he send me e-mail. 

Ze zijn mooi geworden!


Translation : 

They turned out beautiful!




Thanks for sharing the picture Dr OM Jean-Paul

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