This non-powered passive dish focuses cell phone signals to the nearest tower

Was researching ways to communicate when cells don’t work. (Lots of prepping uses, but I was particularly thinking about the recent unrest where gov shuts down signal to protestors.)

Found this and thought it was cool. You put your phone inside of the cradle and that turns it into a hotspot in the middle of nowhere. The tool itself uses no power. So I’m guessing it’s just a signal amplifier. Anyone knowledgeable know how valid this is? Is it or something like it a possible communications prep?


Here’s where I found it

Cell phone hotspot in Australia. Set your phone on the post, dish focuses the signal to the nearest tower. 100% passive, tool itself uses no power.
byu/Monster133768 inThatsInsane


  • Comments (5)

    • 6

      Is this a proof of concept, or something real and in use?

    • 10

      It’s a reflective dish antenna, the same as you would find on satellite dishes. 
      the dish and phone would have to be properly aligned to point at the cell tower. 
      Seems like a good solution for a static location but probably unwieldy and unreliable as a prep. 
      As an analogy think of a flashlight. They always have those reflective parabolas behind the lightbulb. The reflector focuses the light and makes the spot brighter or more spread out. The reflector itself doesn’t use any power, it’s just a mirror with a special shape. 
      For the booster, the big dish is the reflector and the cellphone is the lightbulb. 

      • 6

        That’s pretty cool. I’d be tempted to try and make one out of an old antenna. I know some people jerry rig boosters for their cell service using the old hardware which was actually pretty good. I think the newer dishes aren’t as modifiable but I’m not sure.

        I assume you’d have to get the angle right (pointing to the nearest cell tower) but that would be trial and error anyway.

    • 2

      I found a whole page about this particular one with a video:


      Here’s how it describes the way it works:

      What is the CfAT Ltd Mobile Phone Hotspot?

      The CfAT Ltd Mobile Phone Hotspot is a one-user-at-a-time facility to extend mobile coverage in fringe areas with poor coverage

      The CfAT Ltd Mobile Phone Hotspot consists of a concrete or platform base, a parabolic dish antenna and post, and a pedestal /cradle to hold the phone

      It requires no power, has no moving parts, and therefore requires virtually no maintenance

      How does it work?

      By aiming the Mobile Phone Hotspot Dish at the nearest or most suitable tower is captures more signal than a phone’s built-in antenna, and focuses this stronger signal down to the cradle top where the phone sits.

      The phone can be used in loudspeaker mode, or as a personal hotspot.

      When it says “one-user-at-a-time” I guess it means only one phone. But you could bring people I guess and just share your hotspot password and everyone can connect?

    • 4

      They should install things like this in national parks or in camping areas where service might not be that great, and the return on investment of installing a new cell tower in the area is too low.

      I can see this being able to save lives if people are stranded. Instead of having a lost hiker climb a mountain where there may or might not be a signal, you can give people a map with these dishes pin pointed so people know exactly where to hike to and don’t risk their lives looking for a signal.

      Does anyone have a large piece of land where they don’t get the best service? I’d love to see someone try and use an old satellite TV dish and mess around trying to get some extra bars. They then can set that up on the far end of their property and know that if they are out there and need to reach help, they have the ability to do so.