DIY 2G/3G/4G Wireless Cell Phone Signal Booster




Before begin. Where i stay is a rural area., cell phone signal reception is a nightmare. 1 bar or no service, the best i can get is 2 bar. After a long searching for a solution, trial and error. Discover this simple solution without purchased a expensive 3G signal booster. Here the guide to build one from household items.

DIY 2G/3G/4G wireless cell phone signal booster is a home-brew booster which uses common household items. This DIY can improves the signal of cell phone signal inside your house, from 1 bar to full. You need to build 2 unit, one indoor, one outdoor, both unit is similar and simple to build if you follow this guide, but i take few hours to R&D. I name it, LauC2 antenna. Before we start, safety first wear protector eye glass and safety gloves. When you see the bold text, is special for people want details instruction. This project can build using material you can found, finished LauC2 antenna have to 80% like the photo. Primary objective is E GSM 900, 2G signal reception. You need at least have cell phone signal coverage at outside your house for this antenna to function and working, 1 bar signal strength or come and gone.

Use the phone as usual, not wired. No wire connected to your phone.


First get all this items from your house :

  1. iron wire from clothes stand / wire coat hanger, [double check using a magnet is iron], 2-4 mm iron wire. Or you can get iron wire without paint coating to improve efficiency.
  2. two piece extend electric cable connector block, 20A [if any]
  3. common cable TV cable / coaxial cable / satellite TV cable, 30 meter good quality coaxial cable , no cut and joined.
  4. wire cutter
  5. pliers
  6. screw driver, 3-6 mm phillips screw drive and slot screw driver.

You can found all this items at your nearby supermarket, hardware shop.

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Step 1: Start Building Antenna, LauC2 Antenna

Look at the drawing. First section we going to build is the 3G antenna using the iron wire from the clothes stand /wire coat hanger, the black color drawing. Not necessary to remove the paint coating.

Straiten the clothes stand wire / wire coat hanger with pliers [ i using hand ] and bend it 4cm at the corner about 45 degree.

  1. Then measure 8cm from the bend and bend inwards at 90 degrees.
  2. Then measure 9cm from the bend and bend inwards at 90 degrees.
  3. Then measure 9cm from the bend and bend inwards at 90 degrees.
  4. Then measure 8cm from the bend and bend inwards at 90 degrees.
  5. Last bending is same as the first bland 4cm about 45 degree where install extend electric cable connector block, insert the connector block to the ends of the both end of the wire and tighten it.

All wire is connected inside the connector block. The 4cm area, clean/remove the clothes stand / wire coat hanger shield [paint coating]. You have to use the wire cutter to cut the wire. Build 2 unit. One clothes stand enough for building 2 unit this kind of antenna. Maybe take you 1-2 hours or less.

Next step is the wireless antenna, the orange and yellow drawing. This section we need to use the common cable TV cable. So first cut off the plastic jacket about 15-20 cm length, depend on the center core round / turns , if you planning for testing the center core round / turns, maybe good idea about 20cm. depend on the center core round / turns diameter. Now you can see the [metallic shield] like a spider web, cut off this metallic shield and look at the drawing again, the red line is the metallic shield to be installed. No waste. Just twisted down the metallic shield become a wire without cutting [cut it if too long ]and fit into the connector block at the red line and tighten, not necessary a U shape. Then back to the cable, cut off the dielectric insulator carefully, we need the center core for building the wireless antenna.

Back to the drawing again. About 5cm from the edge of the center core [ or start at plastic jacket edge depend on the length of center core ], we need to make 5 round / turns clockwise, E GSM 900 2G, we can do it using screw driver [ 3-6 mm phillips screw drive ], just bend the center core round and round / turns on the rod. Then straight the center core both area like the photo. Now we need to mount this wireless antenna to the 3G antenna. Look at the drawing how this done. Remember the edge of the center core wire have to joined the iron wire and tighten. Do not forget the red wire.

After some testing, B1-WCDMA 2100, 4G have to be center core 7 round /turns at outdoor unit, and center core 5 round / turns at indoor unit. Use your smartphone searching for the location have STRONG 4G signal to put the outdoor unit.

A good signal strength define is maybe a stable 3 bar 2G signal, not a unstable signal strength jump up and down too often. Probably take a while for getting the right place.

If you not very sure, just make it 7 round /turns at out door unit and 5 round /turns at indoor unit. If the signal strength still too weak, you can trial and error increase the outdoor unit the center core round / turns 1 at a time. 1 round / turns mean 1 complete circle.

So you need both edge [ cutting edge ] of the cable to be the wireless antenna. Better install the cable one end at the roof top or near roof top, open area. One end is inside the house, anywhere you like.

Completed assembly, both end of the TV cable have a finished LauC2 antenna like the photo.

When you finish building 2 unit of this antenna. One unit install at outdoor where you can get STRONG cell signal strength and the front [flat area] of the antenna have to face vertical to cell tower, somewhere. Adjust the LauC2 antenna until you satisfied with the signal strength, test using your phone, recommended phone set to 2G for antenna adjustment purpose. Stay away from any wire mesh, object blocking, wireless device. Can put inside house window where can get good signal strength. if your house have lighting strike history, keep the antenna at secure location.

Now the indoor unit, anywhere you like where you want to put the antenna. Recommended at height area and open area for better indoor reception [ or center of the hall ceiling], and the location you always busy with your phone and keep distance with the wireless router. Just one condition, vertical or horizontal. Why? you asking? Take your phone, if antenna is vertical, phone also vertical getting strong signal strength. 2G signal always have better cell phone signal reception, tested device Nokia 1110i, 3 bar or full . Lumia 635 2G can get 3 bar signal. Moving too far away from the Lau2C indoor unit antenna, signal drop, tested 20-25m still have 2-3 bar. 1-3m i get full bar using Nokia 1110i.Smartphone always having poor signal strength.

Take off your smartphone additional phone case, some phone case really weakening the reception. If everything all right, you can dial out and received income call, even the phone show weak signal inside house, all phone carriers do have a free call customer hotline, dial the number and listen the audio quality.

The antenna no insulation part should not touching the wall or electric conductor.

If you want some dB value, enter Field Test mode on your smartphone

  1. Nokia / Windows Phone, dial ##3282#
  2. iPhone, dial *3001#12345#*
  3. Android, access Settings>General>About Phone> Network or Status

Closer the value to -50dB, better the signal strength

Step 2: Cooking Aluminum Foil

You also can cut a small piece of cooking aluminum foil, about the phone
side body thickness and length. Put it on the left or right side and hidden inside the phone case. To boost 2G signal. in this case i'm using a Nokia Lumia 635 Rubber Silicone case bought from eBay. You can see the photo, is Nokia 1110i, aluminum foil fit inside the transparent phone case.

Somehow you also can use your phone headphones work as an Antenna too, many people over look this.

Step 3: Additional Wire

Look at the photo above. I added additional wire. something i am trying todo is increase the indoor unit smartphone reception. is additional, trial and error. You only need to cut 1 piece 30cm center wire, from the one edge about 5cm, 4 round / turns on the pencil body then pull a little bit on the wire. Then fit at one of the join, depend on your antenna. This not increase the signal strength. Show promising result.

Step 4: Version 2.0

The version 2.0. Kind of science fiction, have 3 assembly in 1. this design show more promising result, but you still have to install it at the right location, where have a consistent stable cell signal strength for outdoor unit. Picture coming soon.

Assembly 1, step by step guide

  1. straiten the iron wire coat hanger.
  2. bend it 4cm at the corner about 45 degree, only this area have to remove the paint coating.
  3. then measure 8cm from the bend and bend inwards at 90 degree.
  4. then measure 9cm from the bend and bend inwards at 90 degree.
  5. then measure 9cm from the bend and bend inwards at 90 degree.
  6. then measure 8cm from the bend and bend inwards at 90 degree
  7. then from the bend rotate 90 degree.
  8. then measure 9cm from the bend and bend inwards at 90 degree.
  9. then measure 10cm from the bend and bend inwards at 90 degree.
  10. then measure 10cm from the bend and bend inwards at 90 degree.
  11. then measure 9cm from the bend.
  12. Last bending is same as the first bland 4cm about inwards 45 degree, and remove the paint coating.
  13. End to End 4cm iron wire fit into the connector block and tighten.
  14. so is inner 3G antenna and outer 3G antenna in 1.

Assembly 2, step by step guide

  1. you can use the existing 3G antenna or follow the guide at Step 1 .
  2. the End to End 4cm area, just measure a sufficient length that can fit into the connector block, maybe a 1cm.
  3. bend both End 90 degree forward.
  4. replace the red wire with this assembly, meaning this assembly is horizontal at the center of the assembly 1.
  5. fit into the bottom of the connector block and tighten.

Assembly 3, step by step guide

  1. the wireless antenna. almost same like the old design.
  2. 7 turns for outdoor unit and 5 turns for indoor unit
  3. the length have to reach the bottom of the assembly 1, you can pulling a bit.
  4. fit into the connector block and tighten.

Note : You also can bend this antenna just using one piece of iron wire without paint coating without any cutting too. and also can adjust all the antenna to different angle to improve efficiency.

Step 5: Wireless Router Antenna Modification

This what i done to my Dlink 2750E ADSL N-300 Wireless router, as pictures show you. By this simple modification on the wireless router antenna, the antenna is attached on the router antenna. I able to get more reliable internet through a solid concrete wall, example wireless signal broadcast to my room, in between have a solid concrete wall. You can try this.

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306 Discussions

Lau Han Ching

3 years ago

i just modified and attached my Dlink 2750E antenna with this antenna, so fast it show better internet experience., if have a solid concrete wall in between. Dlink 2750E is a ADSL WiFi-300N router.

2 replies

No matter how much you modify and sophisticated it can be when the signal is low the antenna can't do anything about it. This has been proven in a low signal zone and the antenna becoming very sensitive to positions which means a little of wrong position on the signal will be lost.

You will need an amplifier to help the signal regenerate (reamplify) itself so that it can be faster

RobertM550Lau Han Ching

Reply 3 years ago

you mean for the indoor? can ypu show some pictures of it? thanks


Question 1 day ago on Step 5

How do i test the booster is working without imminent presence of poor reception.


4 days ago

It works for me. I live in a mobile home where the cell signal is not great anyway. After setting up the antenna and messing with it having trial-and-error problems just experimenting I finally got a successful signal and last month when my monthly contract with att was almost over and ready to be renew. I check my network connections and it said only 4% of my data from my monthly plan was used the rest of my usage was on my Wi-Fi signal... this proves everything that that booster works and I'm still working on a way to boost it even better


Question 10 months ago on Step 1

I am making unit now but need to know is the outside and inside units hard connected with the coax? Or is the coax cable just used to suspend the antenna?

1 answer

Answer 4 days ago

Yes the two antennas are connected by the center conductor which of course is not cut or coupled together by any means it has to be one 1 wire


7 weeks ago

Made it and like most of the posts it does nothing I'm just glad I read hosseinE5 post because I was just heading out to try a hole bunch of different things trying to make it work glad I didn't waste any more time on this. Sorry it just doesn't work so don't waste time on it

Of course NOT! This is not scientific, but just a joke!
Any professional knows that ALL passive devices just weak more and more and more the signal, so, even it could be of STRONG GAIN antennas (which they ARE NOT!), the lenght of the coaxial cable were enough to destroy completely the strength of signal received!


4 months ago

I don’t think I’d
want to take a chance with the FCC breathing down my neck when it comes to cell
phone boosters. While this DIY booster may work, I’m not sure if it’s legal to
use. This site has some useful information on cell phone boosters, boosting
signals w/o boosters, and the FCC’s requirements. Don't get me wrong, I think it's cool how you made one but I'd check on the legal requirements.


Question 1 year ago

Hi, for the cell phone booster, how important is it to use 30m of coax? I live on a boat so was hoping to be able to use a shorter length.


2 answers

Answer 4 months ago

30 m is important for wave length and carrier signal however you can coil up excess inside your boat in a cabnet or bulkhead
I hope this helps


Answer 1 year ago

length of coax not as important as distance between outside and inside antenna. I you read up on commercial units. Another way you might accomplish this is to change your outside omni-directional antenna to more of a directional one by shielding side of antenna facing internal antenna with a foil sheet grounded to the external shielding of coax wire. Perhaps a copper wire extended into the water then attached to shielding might help but just a guess. Of course if you are stationary then commercial AC grounding wire would be best. Another thing, which you do not address is if your boat is mobil? In this case distance is your only option between antennas perhaps by using a pole extension and outside antenna would need omni-directional configuration because you could not guarantee you had the outside antenna in the optimal position.


4 months ago

Made it exactly as you did and it works perfectly! I have al alarm system in a shipping container that can't get a phone signal, seeing as it's in a farraday cage... Put one end in the container and the other outside and bingo! It works perfectly! Really, thanks so much!


Question 5 months ago

Can anybody post a source or buzzword so I can study the theory to dimension the antenna accordingly to my providers frequency?


5 months ago on Step 5

how can i boost wifi as shown above if i have a circuit embedded antennae in my router {netgear D500 router}


2 years ago

Very cool project! If I wanted to add an LED to the system so it went off when radio waves were being received by the antenna what would you all suggest??? Don't need to actually boost 3/4G radio waves - just detect if/when they are there. HMU in a comment if you got some ideas!

2 replies

Reply 8 months ago

Use a 4 hole connector instead of 2 hole, that'll give you the spots to place your led


Reply 1 year ago

A weak cell phone signal will not generate enough power to light a LED. Use your phone to indicate the signal strength.