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

Picture of 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.

Step 1: Start Building Antenna, LauC2 Antenna

Picture of 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

Picture of 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

Picture of 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

Picture of 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

Picture of 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.


Lau Han Ching (author)2016-09-06

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.

RobertM550 (author)Lau Han Ching2016-09-08

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

hardwaylearn (author)2017-12-13

I made it. does nothing. I modded it by cutting in half so now 2 dipoles. Used 2mm copper wire. Lead in cable is 300 Ohm twin lead. Still does nothing. I measured signal pre @ -93dBm- using the DUD booster still -93dBm.

Elsicario (author)2016-10-08

Dear Sir, I feel great to write you, I have figured out every thing but not Abel to find connectors could you please let me know another way to get this thing working without them?

jimvandamme (author)Elsicario2017-11-21

You don't need connectors. Just twist the wires together so they make contact or solder them.

AndrewN80 (author)2017-01-17

is there some kind of official name for this antenna so that we can maybe try to analyze how it can be improved??

jimvandamme (author)AndrewN802017-11-21

I'd call it an unbalanced random wire. It will pick up .. something, but nowhere near what a carefully designed antenna will. There's no coax to balanced feed, so some of the cable radiates somewhere.

jFRIESart (author)2017-04-01

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!

jimvandamme (author)jFRIESart2017-11-19

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

todop (author)jFRIESart2017-04-10

You just need a biger antena to capture more radio waves,but the antennas different for different frequencies,so it dificult to make antenna for all the signals.
I was looking for an extarnal GSM antenna for hiking on google because I want to have some better coverage/emergency option when hiking, altrough I have a PLB and a Baofeng UV-5R, a dirrect call to 112 will be nice.

jFRIESart (author)todop2017-04-11

Hum - did you find any particular modifications that are useful for 3 and 4G? I am making multiple of them, so not too picky about getting both frequencies to be detectable by one antenna. Thanks for the help!!

farzinf1 made it! (author)2017-10-27

it doesnt work at all !

KhiptiR (author)2017-08-17

Hi it method has not work

horus_m (author)2016-12-23

sorry mr lau this project has no technical fundamentals, you didnt consider:

losses on coax and the benefict of the coax shield,

the wavelenght, or the sizes of the quad antenna,

the initial and final coils value related to working frequency,

the Zo and the proper insulated conectors for the working frequency.

may be this is working at your home with a strong signal outside,

but is pure chance in most cases.

if you could give us the source of information you got , or the calculation you did

before trying and error test, all we could appreciate it very much and improve it

JoeM22 (author)horus_m2017-05-31

I was wondering the same...seemed like this design was totally without radio-electronics ma work for some by chance...but highly lacking in design priciples for RF and antennea system as a whole.

Even a passive repeater may require proper consideration for line loss and coax length for possible phasing loss

Id like to see a passive systme for 700Mhz with typical lead in lenght for 1/2 ridgid and yagi at one end, dipole at other ( for inside)

chrispen (author)2017-03-05

Does not work for 3G Lau. Not sure how many twists

todop (author)chrispen2017-04-10

Have you made this antenna? Its meant for 2G,you need another one for 3G

HosseinE5 (author)2017-01-24

"absolutely Zero percent effect on 4g"
I had all needed parts so tried it as a holyday project.
Attached it on a 10ft wooden stick verticaly and tied it on tip of the metal bars on the second floor roof clear sky no obstacles in between (no building or trees on that height)
Other tip of the antenna indoor and no effects -115dbm before and after not a single diffrence
On the roof i have -89dbm and something like 4.8 MB download speed.
And yes i tried to test different number of rounds/circles and diffrent positions
Just a waste of 5 hours of off day and a good story for old neighbors to tell each other about the crazy scientist or enemy of the people kind of spy trying to contact the aliens.

todop (author)HosseinE52017-04-10

Did you make the antenna form here,you need another one for 4G

deweyDoesIt (author)HosseinE52017-02-26

Haha thank you sir Hossien. I love the all new make your own death, waste a day, indoor/ outdoor skitzer lighting rod. Sry you had to tred through the labor. Theres no way that would work here in the USA. However CREDIT must be givin for his elaborate instructable

JackS259 (author)2017-01-20

How make this signal booster for cell phone signal?

RanganaP (author)2017-01-17

sir....can i use this for boost 3g dongle signal.......

DanarV1 (author)2017-01-17

Can i combine it with tv booster

NaveenS80 (author)2017-01-17

Sir if i can replace iron wire to copper wire

EvanM85 (author)2017-01-14

Hey so i have a cell antenna but it goes to my router can i use this antenna would it even be better then the one the internet provider brought me

AnubhavP9 made it! (author)2016-12-24


I have already made it. I used to get very weak 4G signals at home. Still I am getting signals of the same strength. Is there any way to test whether it is working or not? Or I need to make some changes, or change the position of the outdoor antenna.

AAZZAA (author)2016-09-03

Great, the bad wireless reception in the mobile home is over.
Thanks :-)

TariqR12 (author)AAZZAA 2016-12-12

aazzaa u lauc antenna working?

Ameliays (author)2016-10-12

Hi.. we already made it, but it didn't work at all....we really disapointed.. is there any suggestion...? Here is my email:

muthukali (author)Ameliays2016-12-06

hai is it working or not?

Michael Heng made it! (author)2016-11-22

Hi Han Ching, I read your instructables. What I came up its 2x10.5cm and 2x14++cm chopsticks, they are just recycled wooden chopsticks. Using one 2.5mm hard copper cable, I go around, then cut another 2.5mm, coil it around a chopstick to make it like telephone cable. It's hard copper cable there, so coiling might take some effort. Thereafter, I use a double 1.76mm power cable, just unskin both cables(less than 1m), then twist them together. Receiver just throw outside windows, then tie the other end to my radio.

Yes, I hear all of you, no near to router, no near to microwave oven thingy. Problem is my DIY Ultimate radio (no need to charge for 1 month) is on top of a PC. When I switch on the PC, the radio becomes disabled due to interference. Now with this mini receiver, I could actually operate both the PC and radio at the same time.

Verdict: Yes, it works. Although it did not follow everything in the instructables, but here is something I did manage to find out. Since the radio antenna itself is also an antenna, not only wireless signal in the room gets a bit of boost, handphone signals becomes better too. Hee. 1 receiver 3 benefits.

leninf1 (author)2016-11-09


Kristi√°nS28 (author)leninf12016-11-14

Why would you ask that? It's not even remotely similar.

Ozzzzz (author)2016-09-28

Where can I buy the two piece extend electric cable connector block? (link)

MikeT196 (author)Ozzzzz2016-10-15

akshayarsade (author)2016-10-09

Is it usefull for 4g network?

YogeshJ14 (author)2016-10-04

still no improvement in my mobile sir pls gudie me to improve the range of 3g

ShivamR21 (author)2016-09-30

Can i make the antenna in triangular shape instead of square

NikoE4 (author)2016-09-22

what if i have outside antenna for broadband and the other side is the LauC2 Antenna, will it work ?

JudeAbankwa (author)2016-09-17

Hi Lau, I happen to have a Satellite dish connected with a coaxial cable but no decoder how can I modify this to boost 3G signal in my room?

MasnsenY (author)2016-09-15

what kind of metal will be best? aluminum, copper or iron ?

diygenius1370k (author)2016-09-08

can i just use solid copper wire is it better or iron is better?

use what you can found

Shirko (author)2016-09-05

Thank you
I want to know cable should be 30 meters absulotly?

Lau Han Ching (author)Shirko2016-09-06


bigredlevy (author)2016-09-04

You provide no theory behind this device, nor do you present any empirical data.

There are so many flaws in this design, for example; your coaxial cable is not even earthed, therefore provides no shielding; your antennas have no balun, so there will be an impedance mis-match with the coaxial cable.

Furthermore, statements like " also can use your phone headphones work as an Antenna too..." are incorrect; Phone headphones include an antenna for FM Radio frequencies, and do not apply to 3G.

GeroE (author)2016-08-29

Lau Han Ching Dude, thanks for this. I've been looking for this a lot this past year.

My comment to this procedure is that the measurement should be precise for best result and the curly thing (Maybe it could be called trimmer) should have a proper measurement (diameter and turns) but I think just a nice turns would do. Man, if it's not too much to ask, can you share the link where did you get this design?

GeroE (author)GeroE2016-08-29

and another thing is use coaxial cable with less resistance ex. RG-8 50 ohm coaxial cable.

bigredlevy (author)GeroE2016-09-04

Nominal impedance of coaxial cable (50ohms for RG58; 75ohms for RG59 and RG6) is used for the purpose of matching the termination impedance of both source and load. Your statement is incorrect.

Lau Han Ching (author)GeroE2016-08-29

and i don't care how ugly the assembly look like, as long it work.

About This Instructable




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