When i'm inside of our apartment, getting a cellphone signal is very hard, often times I wouldn't get any bar in my iPhone. My unit is in the ground floor and is surrounded by tall walls. My apartment has a small balcony (which is still surrounded by tall walls) where I can at least get a single or two bar signal from my iPhone.

This question was inspired by this video (https://youtu.be/pFx8tuSlCcQ) where a guy used some copper or magnetic wire to extend the range of it's mobile phone antenna. I'm aware that there are some repeater that are being sold but they're really expensive. I'm just looking for a cheap (below $10) solution that I can do or buy.

I'm planning to do a similar solution where I'll be extending some magnetic wire from the inside of my apartment to my balcony. But before I do that, I wanted to confirm if this idea would really work.

I also don't know where I will be connecting the end of the magnetic wire as iPhone doesn't have any external antenna port.


closed as off-topic by Leon Heller, PeterJ, nidhin, brhans, Nick Alexeev Jun 24 '15 at 18:00

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This will do absolutely nothing. What you could consider doing is picking up a pair of antennas and a length of coax cable for the correct cell band. I think that would be around 800 MHz. It should be possible to get a couple of cheap 800 MHz antennas and maybe 20 feet of coax with the proper connectors for around $20 or $30. If you know where the local cell tower is, you could consider getting a log-periodic or other directional antenna for the external antenna and mount it so that it points at the cell tower. Note that this may not help very much; it's going to be more useful for, say, a basement that has thick concrete walls where reception inside is zilch and reception outside is very good. If reception outside is only mediocre, then you may have to get a repeater or a femtocell.

  • \$\begingroup\$ Thank you for your response. I'm curious, assuming i'll be able to find some antennas and coaxial cable to do the experiment, where do I connect the end of the cable to my iPhone? would I be winding some wire similar to the video? Thank you! \$\endgroup\$ – Pennf0lio Jun 23 '15 at 21:52
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    \$\begingroup\$ Well, ideally you would connect one end to your iphone. However, if it does not have a connector for an antenna, then you might be able to get away with using a 2nd antenna and keeping the phone close to that antenna. It's going to be quite lossy, but it will be less lossy than the path through the concrete wall. Also, you might be able to get the external antenna up above the wall where it can get a better signal. \$\endgroup\$ – alex.forencich Jun 23 '15 at 22:00
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    \$\begingroup\$ The connector that you would need on your phone looks like the ones pictured here: electronics.stackexchange.com/questions/88041/… \$\endgroup\$ – alex.forencich Jun 23 '15 at 22:04
  • \$\begingroup\$ I'm entirely not sure how this is going to work out but this solution is worth a shot. thank you! \$\endgroup\$ – Pennf0lio Jun 23 '15 at 22:55

No wire, magnetic or not, is going to help. Magnetic has nothing to do with it.

You need either a proper repeater (two antennas and a high gain amplifier), or an external antenna connected directly to your phone with a cable.

See this answer for a detailed explanation with some calculations.

It's not a $10 problem, unfortunately, it's going to take $100-200 to make a difference.


Two ways to do what you're trying to achieve:

Video solution: Assuming some basic understanding of electromagnetic waves, the phenomenon being used here is essentially constructive interference: Any metal pin will be reflecting received signals, thus acting like a tiny emitter itself. If you position the pins in such a way that the reflected waves add up in phase (=distances from the pins to your desired receiver position only differ in integer multiples of the wave length - as an exercise to you.) you can definitely expect an improvement in signal reception.

Using active components: With the solution above it is clear, the you don't actually gain any signal strength: You simply redistribute it smartly. An alternative is to build a circuit that actually amplifies the received signal - As we are dealing with RF design here, this is not an easy task at all. (Issues with gain, linearity, e.t.c. so unless this is your area of expertise you won't get around buying an off-the-shelf solution....)


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