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Inspired by aircraft IFF interrogator antennas, I decided to build my own array - how hard could it be 
As it turns out, not very hard at all 
Playing with antennas at higher (GHz) frequencies means that you can get reasonably good results even at the bench, as shown here. To prove a concept you don’t need large testing facilities, a bit of absorber panel will do 
Found a readymade 4-port 180deg coupler (nick-named a ‘rat-race’) and used two 2.4GHz sleeve antennas, then sweeped a source in front of them.
The deep notch at the ‘delta output’ is clearly visible when the source is positioned right at the mid point, in front of the two antennas.
I’m quite surprised how easy this was, considering the complexity of what is going on here
I have very few friends who’ll understand and appreciate the coolness of this experiment, you know who you are 
@oz1lqo congratulations! one of my course labs in university was doing exactly that. I am still in love with how elegant multiple RF fields can be composed and combined.
@muhanga I was a bit surprised how easy this was I’m considering getting another 3 hybrids and experiment with a 2x2 array
@oz1lqo yeah easy is the right word. As my uni professor once said: "RF waves are easy to manage. Like cats, they will always sit in the box. And you just need to build this boxes for them using basic math"
Looking forward to your 2x2 creation.
@oz1lqo How many RF sources do you have available to you? For something more configurable you can just have separate sources drive each antenna --- obviously this doesn't scale easily to more antennas, but you could steer the beam by changing the phase relationship between the sources (by using a length of line, or if you have phase control on each source). Just make sure that they share the same 10 MHz reference. You would have to tune the amplitudes manually though instead of being guaranteed a ~3 dB split.
@nestes Well, I don’t have unlimited resources in my little (home) lab and I’m not big enough on SoMe to a decent sponsorship 
We’ll see where this takes me, it’s just for fun plays anyway 
@oz1lqo Couldn't tell from the video, that's a nice setup you got there!