Triplexer VHF/UHF/L or S Band

In previous (24/1/2019) IRC meeting we discussed about the GS hardware report and we tried to define priorities about the development in GS hardware.

One of the priorities is to develop a triplexer in VHF/UHF/L or S band. Is everyone interested to write about requirements and specifications about triplexer and then design or make a research about the all ready solution?

As a fantastic example, @ar3itrary designed a diplexer for VHF/UHF with a bias-t.


by coincidence we are working on this, well, a quadriplexer, V, U, L, S band… as soon it will be ready will publish it.

'73 iw1dgg



Nice you can write here about the progress and the specifications, for example the VHF filter is it a low pass filter or a band pass filter to cut out the FM band? What about the insertion losses of each filter?


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Hey, i find this in wiki, could be used as a triplexer.

@iq1ry, do you have any news of the quadriplexer?


Hi, the design is done. We have components and we are waiting for the PCB from
Once it is tested, we will let you know.


Any luck, @iq1ry? Would you like more help in testing?

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Hi all,
We finally managed to have a working quadriplexer. This is how it behave. It need some fine tuning at L-Band and S-Band since we used standard substrate with unknown RF behaviour, which apparently is not perfect for high frequency.
Since we also made a mistake in sending the order, we had to do vias our self, so the final result is not perfect.
We are currently thinking to order new PCBs, may be on a better substrate to make it more predictable. We may also order it already mounted since we used 0603 components which are a bit tricky to mount.

We are just wondering whether there is someone interested, to share the order.



@iq1ry Very interested - count me in…

Yeah, I’m also interested! Possibly also in two!

I may also be interested. :slight_smile:

@iq1ry Any update? Do you have the source somewhere?

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@iq1ry I’m curious if you were able to use the quadriplexer (and even better, if you have it published somewhere?)


Hi,! apologies for the late answer. With the Covid, etc, spare time is almost 0…
Now, we did build a working prototype. But the PCB had some errors, so now we are aiming to make the final version.

'73 Iw1dgg, Marco


anyway the first prototype was working quite well…