Phone signal booster

Thread Starter

MCH170

Joined May 13, 2021
12
Hello, I was looking around for a phone signal booster schematic but most (if not all) results I found were fake. I don't know much about wireless communication so I apologize if my question is stupid. Would it be possible to build a device that uses a high gain antenna to communicate with cell towers and a smaller low gain antenna to broadcast to phones in its immediate area? Something sort of like a wifi signal booster. Just to be clear, I am not hoping for miracles, just something that turns a weak signal (<1 bar) into one capable of supporting a basic phone call. Thanks for your time.
 

Ya’akov

Joined Jan 27, 2019
6,546
The problem is building such a device would not only be complicated but illegal. There are devices you can buy, but they have to be approved by the mobile carrier because technically they operate on the carrier’s license.

One approach that can be successful is a passive repeater. The idea is to mount a gain antenna pointed at the cell, something like a Yagi-Uda or corner reflector on the operating band for the cell then connect is with the shortest practical run of low loss coax to an omni directional antenna inside.

The short, low loss coax is required because the feed line losses at cell tower frequencies is quite high and the signal is very small. I know of some successes with this approach and some failures. Your success depends on:

Field strength of the cell at your location
The quality of the coax and antennas
A good line of site location for the antenna that is close to the place that needs the coverage. Ideally only a couple of meters away but the actual practical distance will vary with the field strength and the quality of antennas and coax.

It’s worth a try, probably—but also contact your mobile carrier and ask about picocells or repeaters. Picocells are tiny cell sites you connect to your own broadband to provide local service.
 

DickCappels

Joined Aug 21, 2008
9,289
Check with you phone service provider. I have heard of repeaters being given (rented?) to customers in areas with poor reception.

As per Ya'akov's advice about building your own, the transmitter portion must verified to be in compliance with strict standards, and that could easily cost more than most people earn in a year. Rather than coming up with a list of probable problems, I can say this: It is not a project for a beginner -cell phones are designed by teams of specialists.
 

Thread Starter

MCH170

Joined May 13, 2021
12
Thanks for the advice guys. I was looking for a cheap and easy solution for a camping site. I guess its more trouble than its worth for one week a year.
 

Ya’akov

Joined Jan 27, 2019
6,546
The simplest solution may be found to the querry word "Cantenna"
How do you propose to connect an external antenna to a mobile phone?

EDIT: Sorry, that might have come off as harsh, not my intention. But if an external antenna was an option, simpler—though not as cheap—would be to buy a commercial Yagi-Uda or a directional antenna of some other design. They will have better gain, and they would be plug and play—if one could plug…
 
Last edited:

Janis59

Joined Aug 21, 2017
1,482
How do you propose to connect an external antenna to a mobile phone?

EDIT: Sorry, that might have come off as harsh, not my intention. But if an external antenna was an option, simpler—though not as cheap—would be to buy a commercial Yagi-Uda or a directional antenna of some other design. They will have better gain, and they would be plug and play—if one could plug…
Its enought to place the phone micro-antenna into the focal point of dish. Its plethora of videos in the russian web demonstrating how it may be done, where towers may stand more than far away.
 

Janis59

Joined Aug 21, 2017
1,482
And secondly, if really have ideas about to use external antenna, many phones have clear separated RF part ending with plug to antenna. If have such model, just knot ite phone in the wire`s end. Its not the worse than no signal at all.
 

DickCappels

Joined Aug 21, 2008
9,289
20 years ago cell phones with antenna connectors were pretty common -that's how I got on the internet back then while living out in the sticks. I haven't see a phone with that connector on it for a very long time.

There were cradles back then that a phone was set into while in use, it appeared to me that they antenna in the phone coupled by some wireless means and then passed the signals to and from a length of what appeared to be RG58/U running up to a beam antenna mounted high up outside.

How did that cradle work, and how big of a job would it be matching it to an antenna and feed line.

Maybe a more important is whether @MCH170 thinks that this would be a suitable solution to his need. This something they would use during a week of camping. Not sure they would want to pack a Yagi and antenna mast along.
 

sagor

Joined Mar 10, 2019
754
There are devices called "repeaters" for cell phones. Basically it has an outdoor antenna and an indoor unit that "repeats" the signals.
However, as I always say, garbage in = garbage out. Unless one puts up a high gain antenna pointed at the strongest cell tower, it will not help much. My sister has one at her camp, and the improvement was marginal in that at least they can get reliable text messages now, but voice is still "iffy" at times. Before the cell repeater, they had difficulty with anything.
 

WBahn

Joined Mar 31, 2012
27,379
Thanks for the advice guys. I was looking for a cheap and easy solution for a camping site. I guess its more trouble than its worth for one week a year.
Turn the negative into a positive -- what's the point of going camping if you are going to still be connected at the hip to society by your phone. Plan your camping trip to be a camping trip -- unplug from the world for a week and slow down and enjoy a break from the hussle/bussle.
 
Top