Mobile Phone / Wireless Internet Antennas/cables + WiFi

Discussion in 'Networking, Telephony & Internet' started by LostBenji, May 28, 2011.

  1. LostBenji

    LostBenji Member

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    Up a tower somewhere....
    I have worked in Telecommunications and Radio since my time in the Meet-n-Greet (Meet with Hot lead or Greet with cold hard steel) department of the Army (Infantry 1 RAR FTW) and have seen it all at one stage or another. I now work in several Fields covering Radio & Telecommunications through to tech-support for several Wireless ISP's as well as being an Electronics Tech and a Rigger. Also have Aircraft and Electrical engineering in the there as well but thats for another time.



    NOTE: If you wish to add links to other info pertanant to the discussion, please do so but if you wish to add homemade or cheap-arsed bandaids to thread then please don't. I have made this thread to get away from the shoddy back-yard crap that either doesnt work, cause issues on the networks or to other RF devices or is dangerous. If you fee you need to discuss back-yard stuff, please do it elsewhere.



    I have been seeing lots of threads and posts as well as getting a lot of PM's asking regarding getting WiFi and mobile based BB working in areas that have less than idea signals or other factors limiting the best performance of the afore mentioned. Unfortunately, there is not many people in my Fields who are experienced enough to really answer these questions but that doesn't stop all the forums ExSputrs adding their 2 cents and giving either bad or dangerous advice. The end result is that those of us who are clued up, either don't waste our time or go elsewhere. If you feel that you are one of these or I and/or others have in the past targeted yourself then deal with it. Anyway, to the point and details.

    Mobile BB

    Where most people get it all wrong is the simple principle of a Transceiving device, it needs to receive a signal and also transmit the return signal. The cell towers can run up to the order of kilowatts of output RF power but you tiny modem/phone only has milliwatts of RF power to get back to the cell, in most cases, it is not receiving the signal that is the issue, it's getting back the suffers and has the biggest impact on connectivity and speeds.

    Despite all the claims from all the providers, you need to be a smart cookie when it comes to weeding through all the sales bullshit you get from the shop assistant who is on a sales commission and has very little or no understanding of the claims they make in most cases. The first thing to know is what carrier is using what wholesaler's gear to talk to your device. The reason for this is two-fold, it will have a bearing on what you want to do with the internet (different carriers/wholesalers peer to the rest of the world differently) and the speeds/data limits that will follow. The other main reason is that there are vast differences in Radio Frequencies (RF) used by the three main providers, Telstra, Optus & Vodaphone/Hutchinson.

    Now all claim to off coverage to high percentages of the population but as the bulk of the population lives in cities, you do the math. Regional areas suffer, end of story. The way to work around this is do your homework and take the time to get a clue. With this being said, also keep in mind that there people who get a little info and then become wannabe experts who sadly, make bigger mistakes screwing it for themselves or others, forums are home to them and they loved twisted facts and dodgey Wikies. I get these types almost daily and I have a solution for that, walk away or report them.




    OK, the nitty gritty of the RF. I am not going into detail of RF theory here, if you don't know it then ask but it is too bigger topic for here. What you do need to know is the following:
    • Polarization
    • Frequency
    • Types of antennas
    • Coaxial cables and fittings
    • Mountings and Locations
    • Aiming & setup of antenna
    1. Polarization:
      This is to do with how the radio wave travels, this will either be vertical or horizontal. Most areas use vertical only but where there is RF crowding or multipathing issues, then horizontal or mixed can be employed to limit the effects of this. The main thing is to keep your antenna on the vertical plain unless you gain better Tx/Rx signals/performance on horizontal.

    2. Frequency:
      This covers what the carrier frequency is that's being employed in what areas. The best way to find this either use the ACMA site to check what licenses are used in your area or there is a brilliant website made by a person who occasionally pops in here. The site is THIS and can be a very powerful tool when used wisely. Simply hunt down your area and then see what is closest and what they offer. The ACMA site is HERE. The reason for needing top know the frequencies is this, you need an antenna to suit or you are going to be wasting signal or time/money. Telstra operates in the 830-850MHz chunk, Optus is 940-960MHz and same for Vodaphone. Now all three also use the international standard 3G frequency of the 2100MHz band as well however, this is for mainly metro areas as the higher the frequency, the easier it is to block or reflect, it doesn't penetrate things like building and trees well thus not widely used in regional areas.

    3. Antennas:
      The little wire whips on magnetic bases and the likes that you find at tricky-dicks don't even rate a mention in the thread, cheap shit for the those not serious about connectivity. There are several different main types, the most common is the vertical whip or collinear antenna that is omni-directional (receives and radiates 360 degrees all round), the next is a Yagi that is directional and comes in assortment of sizes. The final type is a panel or phased array, these also vary in size and shape but are the best antenna in most cases if your pockets are deep enough. If you think you haven't seen these before, think again, most Cell towers use these. Whips/Collinear antennas are best for mobile situations (vehicles) or where there is plenty of Cell service from one or more cell towers, this will allow the MI-MO to work best if your modem/device supports it. Yagi antennas range from 20cm. all the way up to 4+ meters long. These are for areas that are at long distances from a tower or town with multiple towers that is still relatively open country. The reason for this is that these have a highly focused RF beam and work like a high powered single telescope, you can have all the magnification but if there is something in the way then you still don't get shit. The final type is the phased array/panel antenna. These work by having a wide receiving/transmitting area to allow better performance through things like trees and shit in the way. These work like an array telescope that has multiple telescopes spread out to provide a wider effective area. There is another type of antennas that works like a phased array and that is a grid-pack or reflector antenna. These also work well and can be had for cheaper prices however, can be more difficult to setup as they are highly focused. There are even more elaborate setups where multiple antennas can then be phased together with phasing harnesses but this is specialized and not for this discussion.

    4. Cables and fittings:
      Despite what you might find on eBay, online eTailers or in WIKIes, good cables are not bought of the shelf or online. The best stuff needs to be made to length with the best quality cable you can buy that is designed for the job. TV coaxes (75ohm) are not even to be considered an the same goes for anything you find at the local DikieShit store (full of Tech-Spurts). I have seen plenty of home-made antennas and cables using plain-Jane RG-58C/U or RG-174 and the likes, it just ain't the shit to use, the losses are too high. The cables needed are either going to be a RG-styled Low-Loss (solid core) or bigger LMR-400/CNT-400 that are expensive and hard to work with. The fittings, oh boy, the these will also cost a penny or two and WILL require special tools to do properly. The types should be of the main types and their reverses, N-type, BNC, TNC, FME or SMA. Crappy shit like F-type (75ohm) and 259's are not suitable. These items can be sourced if you take the time and if you can find a dealer nearby. As I said though, cables should always be cut to the length needed and never have excess rolled or bunched up somewhere. Also need to avoid multiple joins or extensions as insertion losses get too high as well. Currently, the best cables on the market are made by an Australian company who is a world leader in RF, "RFI" (RF Industries) www.rfi.com.au
      For shorter runs (under 10M) with decent antennas then the cable to look for is an RG-58 styled cable called 9006 CellFoil. The downside of this cable is that is has a solid core and does not like being bent or moved around a lot. You can also use the 9001 CellFoam for very short runs (under 3M). The more cable you intend to run, the bigger the antenna needs to be to increase Gain. These cables can be terminated in either N-type, FME or SMA fittings but does take a little practice.
      The other final bit is this, any cabling legally needs to be done by a licensed cabler who has coaxial cable endorsement.

    5. Mounting and Positions:
      This area is a grey area as you technically now need a person qualified to be on your roof (working at heights) as well as someone fluent in mounting hardware. The best position in most cases is somewhere that is high and clear of any other obstructions. In most cases, on top of an existing TV antenna pole is common but it needs to be sturdy. The down side of this is that if you are in a fringe TV area with shitty signal and/or have a Mast-Head amp, there is a good chance that your digital TV will goto shit if the TV's AGC is opened up due to being weak signal area. If the TV starts playing up then you need to move the new antenna elsewhere. Always make sure the mounting secure, no point putting several hundred bucks of antenna to loose it in the night. The other things to consider is where the signal is coming from and position your antenna where it get best path to it while keeping the cable run as short as possible. I have had situations where it was wiser and smarter to place a modem in a sealed, outdoors rated box up the pole directly attached to the modem and use PoE to feed it. The reason being is the Cables are expensive and losses get too high. You can be 100M away from the modem with CAT-5e/CAT-6 and it is cheap.

    6. Aiming & Setup of antenna:
      Once you have a decent antenna (assuming that is a directional type antenna) and chosen a good mounting point & method, time to get it aimed and peaked in. Now is best done by two people unless you have a portable "Spec-An". The idea is to have a bunny on the roof who slowly turns the antenna around in a 360 degree circle while you sit on the ground with a the laptop or computer to veiw the logs. What needs to be done is slowly turn till you see a signal, once you get signal pause and wait for the modem to lock on. Signal reading updates off the modems can be sometimes be fast or other times, take nearly a minute to read correctly. Remember, the modem will move through different types of modulation till happy. Now once this is done, move the antenna a little more left or right to find the sweet spot of strongest reading. Mark this on the antenna base plate or on a bit of paper. If you have taken the time use the two sites I linked to way back up, you should already have an idea of the points you want to be aimed at to use as a guide. Ok, now keep turning around to see if there are other cells in ear-shot and repeat the process.
      Ok, once you have the bearings of the cell or cells, you now need to open several command boxes ("CMD") and start continuous pings at several sites, the first being the host site of your chose ISP and the second should be an Australian site that is NOT part of your ISP. The next step is to open another browser window and go to SpeedTest.net and get ready to run it to the servers closest to you. The trick is to watch both the pings and the speeds to watch for packet loss. If the latency is fluctuating wildly then that is error correction working. If you are seeing dropped packets then your aim/signal is even worse. While this is happening you should be moving the antenna slightly to see if it stablizes or drops off totally giving you an indication where you want to be aimed. The key to it is that you want the cell that gives best speed with lowest stable latency rather than the cell with the strongest signal. After you think you have the best spot, lock off the antenna and leave it. For best results, you want the service to be on for 24 hours of testing the above mentioned procedure. Different times of the day/night can yeild different results. Best to be sure before going nuts finishing it off.
      One of the biggest factors affecting speeds is the quality of the signal. If you have poorer signal qualities then you can expect crapppier speeds. He who has a good, clean signal is going to come out best, even when cells are loaded up. The less error correction the systems have to do, the better your throughput.

    Having your cake and eating it to............
    Untill recently, if you wanted to have both a mobile phone and a modem running in same location, you would need to run two seperate antennas and have them mounted well apart to avoid any coupling. This would mean double the expenses and double the fun of getting it installed. Sure, there are plenty who think that just getting a T-peice fitting and joining one antenna to two devices is smart and effective but they are just showing their stupidity and ignorance, I get a couple a week wanting t-peices for just this reason. It doesn't work like that. You have two transceiving devices screaming down the front-end of each other along with screwed matching... FAIL
    However, RFI have just released a new toy, (SP8025-5102-SMA) a Combiner/Splitter. It allows one decent antenna to drive two devices on same or close frequencies (Telstra/Telstra, Optus/Telstra, Optus/Optus) providing your antenna has enough gain and can handle the frequencies spread. There is a loss of 3dB through the device but offers over 30dB of isolation between the two tranceiving devices. The price of these is about $100-120 and well worth it compared to dual antennas/cable runs.


    I will be adding WiFi soon, just got work hanging out my ass at the moment.
     
    Last edited: Jun 14, 2011
  2. CQGLHyperion

    CQGLHyperion Member

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    Nice read. Can't wait to see the rest.

    My old man is ex-1RAR. Vietnam.
     
  3. FiShy

    FiShy Member

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    Good, but it only covers the air interface, smallest part of the network.


    p.s mi-mo is evil :)
     
    Last edited: Jun 3, 2011
  4. trash

    trash Member

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    This should become a sticky!!

    Good starting point for people that are not overly cluey about Mobile BB. I have a ARA signals background also and found your writeup easy to understand follow. My biggest gain from this is the sites that you have linked. It is going to make it easier to find a close tower for my out in the country setup.
     
  5. Audionut

    Audionut Member

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  6. Kyl3

    Kyl3 Member

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    Awesome thread is awesome!

    I live in Muswellbrook, about 10k's from telstra tower line of sight with nothing blocking.

    With my little ultimate device I get pretty decent speeds 3-5mpbs varying however I am wanting to go to an external antenna to try and get speeds up a bit.


    What do you suggest?
     
  7. OP
    OP
    LostBenji

    LostBenji Member

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    Location:
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    If your cable runs are going to be kept short then a about a 5 element Yagi will see some good speeds. If you had Cells closer then a Verticle Omni would also work but at 10K, lets not push our luck.
    If cable runs are to be longer (10M+) then I would suggest something in the 10-15 element area to provide more gain to offset cable/fitting losses.
    Don't forget a patch lead to suit the modem and use port 1 on the modem.




    Thank you to all those who PMed and emailed after the recent crap. I will make more changes and updates soon. Sabertooth kind now. lol
     
    Last edited: Jun 11, 2011
  8. FiShy

    FiShy Member

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    Blue is bad mmmkay, alot of people still use sabretooth.
     
  9. OP
    OP
    LostBenji

    LostBenji Member

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    WiFi will be added soon, there are plenty of write-ups so far but will cover the basics as well as the nitty gritty that has been missed so far.
     

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