Sending internet around the Aerial circuit

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  • TimH
    Automated Home Legend
    • Feb 2004
    • 509

    #16
    Originally posted by michaeldon View Post
    Just wondering. You say cisco is no good for repeating?
    I think the point was that you'd normally select different channels for adjacent access points to avoid interference. Configuring all access points for the same channel means the signals bleed over each other and your overall range is significantly reduced.

    HTH,

    Tim.
    My Flickr Photos

    Comment

    • michaeldon
      Automated Home Jr Member
      • Jul 2009
      • 23

      #17
      Hi Tim

      the reason we have 4 ADSL lines is that we found it unworkable to repeat 1 WIFI signal throughout the building. Of course we are using multiple channels so I don't think interference was the main issue.

      Just a note - this building is not in the UK so I don't know the coax cable impedance. In any case we have many buildings in many countries we'd like to find a general solution for.

      If you have info about internet through power lines working past meters that would be very interesting

      Regarding the tenants, we have control over all the flats so we can get in and out when we want to but I would have trouble with the building owner running ugly cables in the stairwell or drilling through walls and windows.

      Comment

      • Gangsta
        Automated Home Jr Member
        • Jan 2010
        • 40

        #18
        Why not just buy any 'old' hub, and wire it 10base2, connect onto the coax you have - job done. just make sure you install safertap (or similar) as the outlet in each apartment, or on the droplink to prevent disruption to the other apartments.

        You can probably pick up everything you need at a local it recycling place for a couple of quid (they may just tell you to take it away), and 10Mb is usually way more than you use for the interweb anyway.

        I know my 24 port hub has coax connectors, and up till a few years ago it was still in widespread use in 'cheapo' government departments who wouldn't fund the upgrade to cat5.

        Here is a suitable hub, on ebay for £1 http://cgi.ebay.co.uk/Accton-16port-...a#ht_500wt_975

        the coax goes to the bnc connector on the back
        Last edited by Gangsta; 25 January 2010, 09:22 PM. Reason: added ebay link

        Comment

        • TimH
          Automated Home Legend
          • Feb 2004
          • 509

          #19
          Originally posted by michaeldon View Post
          Hi Tim
          the reason we have 4 ADSL lines is that we found it unworkable to repeat 1 WIFI signal throughout the building. Of course we are using multiple channels so I don't think interference was the main issue.
          I would've thought (as the other poster suggested) that one DSL line and router with multiple access points would work, the challenge would be cabling between the APs.

          Originally posted by michaeldon View Post
          Just a note - this building is not in the UK so I don't know the coax cable impedance. In any case we have many buildings in many countries we'd like to find a general solution for.
          I did wonder
          I'm not sure it matters though, I would expect 75-ohm universally.

          Picking up on the earlier references to MoCA (http://www.mocalliance.org/)
          The description sounds exactly like what you're after, but I wonder whether any of this is "consumer" yet, or whether its for the large cable-tv companies.

          There's also this this from May 2008: http://www.engadget.com/2009/04/20/d...rnet-adapter/2
          which looks like it would do the job?

          Originally posted by michaeldon View Post
          If you have info about internet through power lines working past meters that would be very interesting
          unfortunately not. A practical test would be reasonably inexpensive though...

          Originally posted by michaeldon View Post
          Regarding the tenants, we have control over all the flats so we can get in and out when we want to but I would have trouble with the building owner running ugly cables in the stairwell or drilling through walls and windows.
          Trying to think a bit laterally - each flat has its own electricity meter (AIUI) so the tenants are individually billed for their consumption. But there must be "common" areas, lift/stairwells, corridors, etc. and presumably these are lit.
          If you went powerline-ethernet to light fittings you could take advantage of the cables already run and locate access points in the common areas. If necessary then bridge between an AP inside the flat and the common one outside. Once inside the flat you could go to more powerline-ethernet to distribute the signal internally.
          That avoids having to pass the signals through the individual leccy meters (if proved not possible) while still taking advantage of existing building infrastructure as far as possible. False ceilings in the corridors would be ideal to hide the APs behind but it obviously depends on the age & style of each building.

          HTH,

          Tim.
          My Flickr Photos

          Comment

          • michaeldon
            Automated Home Jr Member
            • Jul 2009
            • 23

            #20
            Thanks for the ideas Tim. I actually did think of using the hallway lighting circuit to distribute the net but I wasn't sure if it would work because I have no idea if live/neutral and earth are all cabled to these hallway switches and what the effect of a 220v device sitting across live and neutral would be, especially when someone closes the switch. As you can tell I am no electrician

            Elevator power might be an option but it also means a lot of messing about and with power lines I may have no access to.

            I really like the idea of using 10 Base 2. Very clever. Would it work on 75 ohm cable? I found this on Wikipedia:

            "Antenna network 75 ohm
            A terminating resistor for a television coaxial cable is often in the form of a cap, threaded to screw onto an F connector. Antenna cables are sometimes used for internet connections; however RG-6 should not be used for 10BASE2 (which should use RG-58) as the impedance mismatch can cause phasing problems with the baseband signal."

            Comment

            • toscal
              Moderator
              • Oct 2005
              • 2061

              #21
              Originally posted by TimH View Post

              Old-skool networking was on coax but 50-ohm (IIRC). Aerial cable is likely to be 75-ohm Maybe some products would still work...


              Tim.
              The aphelion stuff is designed to work with normal aerial cable so 75 ohms.
              I remember the old 50 ohm network stuff too. Never had enough of those dam termination plugs.

              One problem may be with the ISP. They may not like it that you are using one DSL line for multiple users.
              Which countries are the flats in. You may find that one solution in one country won't work in another. The way buildings are built in Spain especially the older ones means that Wifi signals don't travel that well. They have a rebar ring beam top and bottom, in each room, that is tied together with vertical rebars at the corners and its usually also tied to earth as well. So its almost like a basic Faraday cage.
              Most aerials that come with access points are rubbish, I would change the aerial for a better one. They are not that expensive. I did this in my house and the signal is reasonable in the bedroom and kitchen now. Couldn't get anything before.
              IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.
              Renovation Spain Blog

              Comment

              • michaeldon
                Automated Home Jr Member
                • Jul 2009
                • 23

                #22
                Yeah, Bingo Toscal. This test building is in spain.

                Comment

                • jpdw
                  Automated Home Guru
                  • Oct 2007
                  • 169

                  #23
                  A bit OT now, but to answer some specific questions...

                  Originally posted by michaeldon View Post
                  Thanks Jon,
                  Just wondering. You say cisco is no good for repeating? Who is good and what's the difference?
                  How many times can you repeat a wifi signal before you get significant degradation?
                  Doing multiple hops over WLAN will always cause degradation due to a couple of factors - delay going through each AP and interference. In any 802.11g deployment in the US & EU you can only get 3 APs on channels that dont overlap to some degree. In the EU we can, with a tiny bit over overlap squeeze 4: 1,5, 9 & 13. Having any overlapping APs and they will cause a level of interference & degredation. Enough to bother you? depends on what you're doing. A little bit of web surfing maybe no real issue but video er...ouch. You get the idea.


                  Originally posted by TimH View Post
                  I think the point was that you'd normally select different channels for adjacent access points to avoid interference. Configuring all access points for the same channel means the signals bleed over each other and your overall range is significantly reduced.
                  Tim.
                  Tims right, and here's where multiple hops will add to your interference woes as you're using channels to hop out to the APs. Which reduces any remaining unused ones. Worse, it means your link from ADSL to laptop is now subject to interference-caused retries on more than 1 wireless hop. So there is 2x or 3x the chance of retries ... which cause delays, missed data packets etc,. Again, how annoying this is will depend on what you're doing.
                  There are actually 2 vendors in the world that do work on a single channel but thats a differnet story and aimed at enterprises anyway... but for everyone else including Cisco, this is a no-no

                  Originally posted by michaeldon View Post
                  Regarding the tenants, we have control over all the flats so we can get in and out when we want to but I would have trouble with the building owner running ugly cables in the stairwell or drilling through walls and windows.
                  Out-of-the-box idea: I know somewhere where the APs are mounted in the garden outside, pointing inwards ! Maybe/may not be an option.
                  Jon

                  Comment

                  • toscal
                    Moderator
                    • Oct 2005
                    • 2061

                    #24
                    Whereabouts, I'm near Alicante.
                    If you use repeaters rather than APs don't you halve the bandwidth available. I have never had much success with repeaters.
                    Last edited by toscal; 26 January 2010, 11:22 AM.
                    IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.
                    Renovation Spain Blog

                    Comment

                    • michaeldon
                      Automated Home Jr Member
                      • Jul 2009
                      • 23

                      #25
                      We have places in Madrid but this building is in Barcelona.

                      I wasn't aware that APs and repeaters were different gear. Pardon my ignorance. I think now we us APs configured to repeat the signal.

                      Comment

                      • TimH
                        Automated Home Legend
                        • Feb 2004
                        • 509

                        #26
                        Originally posted by TimH

                        Old-skool networking was on coax but 50-ohm (IIRC). Aerial cable is likely to be 75-ohm Maybe some products would still work...
                        Originally posted by toscal View Post
                        The aphelion stuff is designed to work with normal aerial cable so 75 ohms.
                        I remember the old 50 ohm network stuff too. Never had enough of those dam termination plugs.
                        Agreed
                        I was wondering whether you'd get anything useful out of 50-ohm network switches attached to 75-ohm cable.

                        You'd certainly get better performance out of kit *designed* to work with aerial coax though

                        Cheers,

                        Tim.
                        My Flickr Photos

                        Comment

                        • michaeldon
                          Automated Home Jr Member
                          • Jul 2009
                          • 23

                          #27
                          What do you think about something like this Tim?

                          Is a high output wifi a possibility? Or will it just have problems getting signal from the laptop users?

                          Comment

                          • toscal
                            Moderator
                            • Oct 2005
                            • 2061

                            #28
                            Another solution is to use leaky cable. I think its actually called Leaky Feeder Cable and can be thought of much like a hose pipe that is full of holes. The cable basically leaks WiFi signals. Its used in tunnels to maintain radio signal coverage.
                            Its now not that expensive its about 8 pounds a meter,but looks like it could be a what not to install as its about the thickness of a small pipe, diameter is 2.7cm. The way you set it up is you have an access point in the corridor and instead of the antenna you use this cable and run it the length of the corridor.
                            A decent hi power access point costs about 80 to 90 pounds these have dual antennas that both send and receive, so you would put it in the middle of the corridor and then run 2 lengths of leaky cable.
                            Its also used quite a bit in hotels.
                            I can get you more info if you want.
                            Is the building a new one or an old one, and does it have false ceiling or is it that suspended plaster type called Escayola
                            Last edited by toscal; 30 January 2010, 12:14 AM.
                            IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.
                            Renovation Spain Blog

                            Comment

                            • michaeldon
                              Automated Home Jr Member
                              • Jul 2009
                              • 23

                              #29
                              Hi Toscal

                              Thanks for the info. I have never been to the building. I would need to find out.

                              The main point of my exercise was to work out how to use existing cabling in buildings to provide an internet solution. (ie low man-hour cost and no drilling or causing need for repaint when we leave the contract).

                              Re-cabling might be an option in some cases, and in other cases not, however your option sounds good for small buildings where we are in the process of negotiating a new contract. If you have info, please let me know. Thanks

                              Comment

                              • TimH
                                Automated Home Legend
                                • Feb 2004
                                • 509

                                #30
                                Originally posted by michaeldon View Post
                                What do you think about something like this Tim?

                                Is a high output wifi a possibility? Or will it just have problems getting signal from the laptop users?

                                http://www.google.com/products/catal...698&sa=title#p
                                The unit looks "ok", but I’m wary of “recommending” products without knowing too much about the building layout. If signals from the communal corridor won’t reach the lounge then coming in through the window from outside could be a possibility, depending on access, number of floors, number of properties to be covered etc.

                                I wonder whether the newer 802.11 “n” products are any better than the previous “g” ones – ISTR “n” claimed greater speed and range?

                                Toscal’s “leaky cable” was also suggested to me previously by a wireless equipment vendor I was working with on a work project. We had hazardous area issues (it was a hydrogen plant) and there weren’t many (if any) suitably-rated access points available. Their suggestion was to have a survey carried out to determine the best routing etc. but I imagine you could gather a reasonable amount of basic info from the ‘net re: max range etc. However, I would’ve thought that an active device (i.e. an access point) would have better range than a passive cable, but I’m happy to be proved wrong

                                The other thought that struck me was the possibility of providing a “local” adsl service – i.e. giving each household their own router linked back via the existing phone line to a mini-exchange on-site before being connected into the telephone company's network. I’m not sure the costs would pan out for a small development, and the local phone co. may not be too happy either…

                                How good is 3G coverage? Could you offer a deal whereby they rent a USB modem for the duration of their stay? PAYG services are available in the UK for £2 per day, or from around £15/month for a contract.

                                HTH,

                                Tim.
                                My Flickr Photos

                                Comment

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