There are several cell towers on the hills around me. Usually I just walk around their base in a circle with one of the many CellID apps to get their ID. Then I can impress my friends, "That's tower 4664! That's tower 5995!". You know, a sort of hobby.
But now I'm getting kind of old so I'm thinking can I just sit back in my armchair and point some kind of homebrew antenna isolator cannon at them...
If I put my cellphone in a long metal pipe aimed at one of them (I can see the hill with the target tower when looking down the "barrel" of my "cannon"), that will eliminate the signals from the others, and my cellphone will surely now just lock on the one I pointed at... or so I thought.
What are the correct dimensions to make it work? Putting my cellphone in the middle of 1.3 meter length, 15 cm diameter pipe didn't give me any different results than without the pipe.
I'm talking about 4G LTE towers in the 900 and 1800 MHz bands. I put my phone in the pipe pointed at tower A, even pushed the reboot button, but it still ends up locking in to tower B. Hmmm, checking the wavelengths
900 MHz 33.3 cm
1.8 GHz 16.7 cm
Do I simply need a wider pipe? (Certainly even more money down the drain!)