New Stackmatches for ED1R

One of last years projects was the improvement of our Contest Station ED1R. For the various Yagis we needed smart ways to combine antennas. Instead of buying commercial stackmatches (antenna combiners) I decided to build them up buy myself and adjust them to our needs.

HF part

A great resource is Mike’s, SM2WMV (SJ2W) website. Mike is a professional RF engineer and he designed beautiful Stackmatch PCB’s which he also makes available for purchase. Instead of spending hours in designing my own stackmatch PCB, I preferred to buy Mike’s PCBs – especially at this price – a no-brainer.

Stackmatch PCB with Transformer
Basically all I had to do is purchasing the missing components, drilling the holes in the box and installing everything. I used two stacked FT240-61 ferrit cores for the transformers. All the transformers consist of 4 (10m & 15m) or 5 (20m & 40m) trifilar windings of 2mm enameled copper wire. Since impedance is very low (17 – 50 Ohm), no high voltages are expected. That’s why no additional (e.g. Telfon) insulated wires are necessary.

Stackmatch PCB with Transformer and Delrin washers
In order to fix the Balun properly on the PCB I purchased from Hans, DK3YD high temperature resistant Delin washers.

Stackmatch housing
Above you can see the aluminium box I bought at the local electronic store. The PCB fits perfectly into the box.

Stackmatch housing outside
and for outside.

Stackmatch assembled
This is how the stackmatch looks assembled


S11 Measurements with 50 Ohms terminated - all ports
S11 between the Input and the Output Ports is always better than -20dB (click to enlarge)

S21 Port Isolation - Antenna1
Isolation between the ports is between -60dB (7MHz) and -40dB (28MHz) (click to enlarge)

S21 Antenna2 - with Antenna1
S11 and S21 of two antennas combined (3dB Splitting) (click to enlarge)

S21 Antenna 3 - worst case
S11 and S21 of three antennas combined (6dB Splitting) (click to enlarge)

Stackmatches installed

And finally all the stackmatches installed at ED1R above the 8-Pack and the 4O3A High Power Bandpass filters

About Tobias (DH1TW)

Self-confessed Starbucks addict. Loves to travel around the globe. Enjoys the technical preparations of Amateur-Radio contests as much as the contests themselves. Engineer by nature. Entrepreneur. For more, follow him @DH1TW


  1. Paul Spitzer YO5BRZ says:

    Dear Tobias!
    I just need (like a last band from 3,5-28MHz) You HC2/AL1O on 18MHz! 03 may 2013 at 04:42 UTC in 18075,4KHz 2xCW 599/599!
    I see That You have OQSL posibility but I just find one of our old QSO from 20m…..
    How can I received in a resonable time one QSL from You “just” for 17m contact?
    For me OQSL or LoTW is more that OK!
    with friendly! Paul Spitzer Dipl.Eng. YO5BRZ

  2. Bostjan S55O says:

    Mike’s stackmatches are super and we use 6 of them @ S51A.
    Controlling is for now with a push button controller. Works as it should.

  3. Hi Tobias!
    FB work! What type relay do you use for your stack match? Your relay looks very powerful.
    Regards, Mike

    • Hi Mike, I’m using standard 230V / 16A relais. In particular, relais from the company “Finder” – Partnumber: FIN 40.61.9 12V


  1. […] También Tobi estuvo terminando la configuración de los stacks de 10, 15, 20 y 40 y podéis leer algunos artículos con mas información acerca del novedoso sistema que hemos montado en: – New Stackmatches for ED1R […]

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