Solution for 4G reception in a very remote area - Page 1
Forum section: electronics / rf-microwave

author: Jontm
author_rank: Contributor
timestamp: January 18, 2021, 09:20:38 pm
content: Hi!I need to figure out a way to get Internet at a very remote location in the middle of a national park. The main issue is that the loaction is down in a valley right up against a hill in the direction of the only mobile base station in the area. I have currently a large roof mounted Yagi antenna and can bearly get one bar on a good day. This basestation is around 10 km away with a mountain in between. The problem is that this basestation does only have 2G capabilities. The nearest basestation with 4G capabilities is another 5-10 km away with another mountain inbetween. To put it into perspective the closest road is 15 km away and no permanent residents for about 20 km.I need to figure out a way to get 4G Internet to this loaction.The first step is ofcourse to get the biggest antenna possible, size does not matter. It will be roof mounted about 20 meters above ground. I am considering something like the Ultragain 26:https://www.signalboosters.com/bolton-technical-ultragain-26-directional-antenna/Are there any more powerfull antennas avalible for the 800 MHz band avaliable? Is it possible to build something huge with better gain?The second step i am considering is a direct connect signal amplifier. Something like one of these:https://5gstore.com/amplifier_solution/dc_direct_connect.htmlThese are supposed to give about 15 dB gain, but i am struggling to fine one for the 900 MHz band...Would it be technically possible to build a diy bi directional amplifier that increases the receiver gain significantly and possibly also increase the transmission gain ? Possibly higher than the 23 dBm permitted max that 4G modems have ?The purpose is to connect directly to a modem, there will be no rebroadcast of the signal that could lead to signal interference. I am as i said also 10 km from the nearest basestation with a mountain in between and no civilization so i am not to concerned that going above 23 dBm will interfere with anything.Are there any example circuits available for this purpose ? Single-band is all that i can hope for as i think that the 800 MHz band is my best bet for such a distance. Is it as "simple" as a LNA and programmable gain stages together with with some duplexing and filters ? Perhaps there are some ICs that can make the development simpler ?I have access to quite a good lab, have a masters in electrical engineering so not a complete novice even if i gave not worked with micowave circuits before. I do however have knowledge in pcb layouts and finite element electromagnetic simulations.Surely there has to be a way to solve the issue with getting 4G reception ? Even if i have to spend weeks of engineering hours designing and testing something custom?Looking forward to hearing if somebody have some ideas on any of this, any suggestions would be most appreciated

author: Grandchuck
author_rank: Super Contributor
timestamp: January 18, 2021, 09:41:02 pm
content: I would look at a dish antenna.

author: Jontm
author_rank: Contributor
timestamp: January 18, 2021, 09:48:05 pm
content: As in satellite internet ? That is part of the problem, there are mountains in the way blocking satellite reception as well... Apart from the other obvious disadvantages with satellite internet like low flexibility and high price. Even if I was able to get any contact with a satelite...Perhaps it would be possible to modify the LNA circuitry on a 4G modem ? Or perhaps hack a limeRFE to increase power in the cellular bands?

author: Emo
author_rank: Regular Contributor
timestamp: January 18, 2021, 10:18:22 pm
content: Hi, Did you consider a solar powered repeater station on the top of the intermediate mountain. The mentioned distances for line of sight connections are possible then

author: Jontm
author_rank: Contributor
timestamp: January 18, 2021, 10:36:31 pm
content: Yes, I have looked into this. There is a mountain about 15 km away that is close to line of sight that should have 4G coverage. The problem is however that it is illegal to put up something like that on a mountain top, even if I got permission of the people that own the land. At least that is how it is in my country. Mountain tops above a certain height and in nature/wilderness are protected. It might be possible to apply for a permit from the local municipality, but it is very unlikely that they will grant it as they will view it as visual pollution in a preserved wildlife area... There is no natural vegetation that i could hide it in as we are talking about 1500 meters above sea-level. Even if I just put something up without permission, it would be a 10++ hours hike to reach it each time something needed to be reset or the antennas adjusted slightly.

author: coppercone2
author_rank: Super Contributor
timestamp: January 18, 2021, 10:54:31 pm
content: can it be a passive reflectorhttps://en.wikipedia.org/wiki/Passive_repeatertheoretically it might be as simple as some metal painted green, or greyThey used to do this in ancient times by hanging a polished piece of gold up so you know where you can find civilization

author: Bud
author_rank: Super Contributor
timestamp: January 18, 2021, 11:10:49 pm
content: Are you sure you can legally (re)transmit in the band (assuming using an active solution) ?

author: Jontm
author_rank: Contributor
timestamp: January 18, 2021, 11:18:26 pm
content: I mean, it is a restricted band for 4G communication. I have no intention of retransmit the signal and thereby act as a illegal base station. I only want to have a giant antenna and if possible, a boost to the send/receive power so that I reach the nearest 4G base station. There is nothing else I can interfere with, it is in the middle of nowhere.As for a passive reflector, yes I have thought of it, but it would have the same problems as setting up a point to point radio link in that it would require a building permit, something that is practically impossible to get inside a national park.

author: Jontm
author_rank: Contributor
timestamp: January 18, 2021, 11:43:57 pm
content: Perhaps something like the Smoothtalker Stealth m2m X4 if I can get hold of it. Claims a boost of 15 dB, connects directly inline between the antenna and modem and is compatible with band 20. I do however think that it is still only 23 dBm max power, so a bit uncertain how it can get the claimed 15 dB boost. If a can get a antenna with a 16-17 dB gain together with a 15 dB booster, i guess it at least should be quite an improvement and maybe get me close to getting communication with the nearest 4G tower...

author: TheMG
author_rank: Frequent Contributor
timestamp: January 19, 2021, 02:01:36 am
content: I would plot thing on a topographic map and see if there is an "indirect" signal path. I have in the past had good success aiming the antenna toward another hill, in a direction completely different from where the cell tower is located, with great success. Perhaps one of the mountains nearby can be used to your advantage, and all you need to do is aim the antenna a different direction. The best signal isn't always obtained by pointing your antenna in the direction of the cell tower.

author: Foxxz
author_rank: Regular Contributor
timestamp: January 19, 2021, 02:10:47 am
content: I had a friend use one of these. Its like 4-5ft in diameterhttps://www.winncom.com/en/products/GD9-18Build a tower if that does you any good.I've seen people use ubiquiti equipment to shoot long distance links 20km and more.

author: Jontm
author_rank: Contributor
timestamp: January 19, 2021, 09:15:42 pm
content: Yes I have worked with the ubiquity link tool to look at suitable locations for a repeater station, but as said earlier, this is difficult in terms of permits.There is not line of sight from the base station to any mountain tops nearby that I can bounce the signal of, but this is something that I just need to experience with.As for that parabolic antenna, yes thanks, noted. Will check if I can get something like that shipped to my location at a reasonable cost. How frequency specific is it. The base station that I want to reach has both 800 MHz and 900 MHz, but I assume targeting the 800 MHz would give me the best chance of receiving something.Does anyone have experience with direct connect inline cell boosters ? Do they work?I have also looked into building something of my own, but it seems quite difficult to get hold of a duplexer with the correct frequencies ? Are there any solutions more readily available than cavity duplexers that would do the job? Would two antennas with good distance separation work so that I would not need a duplexer?

author: A.Z.
author_rank: Super Contributor
timestamp: January 20, 2021, 08:41:24 am
content: Quote from: Jontm on January 19, 2021, 09:15:42 pmAs for parabolic antennas, have a look at these ideashttp://www.trevormarshall.com/biquad.htmhttps://www.ab9il.net/wlan-projects/wifi3.htmlthose are for WiFi, but the active element may be recalculated for the desired frequency and the antenna is a "recycled" old sat dish; that said, I wonder if you'll be able to obtain good results given that, as you state, you have no "line of sight" toward the nearest base station

author: Syntax Error
author_rank: Frequent Contributor
timestamp: January 20, 2021, 10:46:00 am
content: Personally, your terrain makes this is an application for satellite broadband. Such ashttps://www.starlink.comwhich is now in beta. Starlink is not geosynchronous, so being eclipsed from the Clarke Belt is not a problem.A creative, but expensive solution, is to place your antenna array up the side of that mountain and connect via a single mode fibre. You'll have a good kilometer to play with. How you power the array?....dunno.Maybe go back to an old skool method, and suspend your (omnidirectional) aerial from a baloon/blimp tethered 200 feet above.Or just call the cell company and say you'll rent them land to place a tower - outside of your window.

author: Lord of nothing
author_rank: Super Contributor
timestamp: January 27, 2021, 01:34:26 am
content: @JontmSince I hope you are not life in a Toilet pls tell us where you are from.With all infos we can dig deeper into that think. Maybe you turn your Antenna in a 45 degree angle and see if the are horizontal, vertical or something between is polarised.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: January 27, 2021, 03:38:54 am
content: You have an interesting set of constraints. In your original post you show disdain for legal limits on gain and local interference because of your remote location. But reject solutions offered because they might involve illegal retransmission or other rules violations.By far the easiest solution to your problem is Starlink. Next up, as suggested above is to use natural reflections off of local mountains to get a better signal with a dish antenna. You may be lucky and have a natural parabolic reflector shape coated with mud or moss or other partially conductive material. The only way to find this is to try, with no guarantees. Also look along the edges of the blocking mountain in case you get ducting or diffraction enhancement.I would also not disdain the terrain mapping options. I have lived in locations that would have taken a several hundred meter tower to get line of sight to a desired transmitter, but locations only a few hundred meters away had line of sight at or near ground level. These privileged locations may be in any direction from you, and any extra distance is more than compensated by the improved geometry. Perhaps these nearby locations are easier problems for a repeater or cable, both from a legal and an access standpoint.As it goes on from here most people find it easier to move. But then you lose the perks of living surrounded by a national park. Perhaps if your reasons for living there are related to employment in the park your employers can be convinced of the need for connectivity and would have the political and financial resources to make it happen.