Long Range Wireless Internet

While most of you reading this have broadband in your home, there are still vast areas with little access to the Internet. Ham radio operator [emmynet] found himself in just such a situation recently, and needed to get a wireless connection over 1 km from his home. WiFi wouldn’t get the job done, so he turned to a 433 MHz serial link instead. (Alternate link)

[emmynet] used an inexpensive telemetry kit that operates in a frequency that travels long distances much more easily than WiFi can travel. The key here isn’t in the hardware, however, but in the software. He went old-school, implemending peer-to-peer TCP/IP connection using SLIP — serial line Internet protocol. All of the commands to set up the link are available on his project page. With higher gain antennas than came with the telemetry kit, a range much greater than 1 km could be achieved as well.

[Editor’s note: This is how we all got Internet, over phone lines, back in the early Nineties. Also, you kids get off my lawn! But also, seriously, SLIP is a good tool to have in your toolbox, especially for low-power devices where WiFi would burn up your batteries.]

While it didn’t suit [emmynet]’s needs, it is possible to achieve extremely long range with WiFi itself. However this generally requires directional antennas with very high gain and might not be as reliable as a lower-frequency connection. On the other hand, a WiFi link will (in theory) get a greater throughput, so it all depends on what your needs are. Also, be aware that using these frequencies outside of their intended use might require an amateur radio license.

 

 

46 thoughts on “Long Range Wireless Internet

    1. 433MHz is 70cm hamband :)
      The 900MHz models also work on the USA 33cm band.

      A friend tried piping SLIP and CSLIP over a cheap 2W “wireless serial port” and found out that the built in fifo did not deal well with packets over 64bytrs long and broke them to pieces.
      This played all kinds of havoc with TCP/IP.
      PING worked flawlessly, but anything with larger frames broke.

      I’m slowly working on my own linkhardware based on Si4432 or AX5053.
      If just 1296MHz band capable chipsets ware available and cheap…

  1. A lot of people think that if some people were able to achieve a 210 mile WiFi recoord, they should be able to use WiFi over great distances as well. And they can’t. Why? First, you need line of sight. But line of sight often doesn’t work, because of Fresnel Zones, unless you add even more altitude – often more than is practical. Go read the Wikipedia article on Fresnel Zones.

    1. The main features of the SiK Radio are listed below (see the Advanced Configuration for more information):

      Very small size
      Light weight (under 4 grams without antenna)
      Available in 900MHz or 433MHz (v2 only) variants
      Receiver sensitivity to -121 dBm
      Transmit power up to 20dBm (100mW)
      Transparent serial link
      Air data rates up to 250kbps
      MAVLink protocol framing and status reporting
      Frequency hopping spread spectrum (FHSS)
      Adaptive time division multiplexing (TDM)
      Support for LBT and AFA
      Configurable duty cycle
      Built-in error correcting code (can correct up to 25% data bit errors)
      Demonstrated range of several kilometres with a small omni antenna
      Can be used with a bi-directional amplifier for even more range
      Open source firmware
      AT commands for radio configuration
      RT commands for remote radio configuration
      Adaptive flow control when used with APM
      Based on HM-TRP radio modules, with Si1000 8051 micro-controller and Si4432 radio module

      1. Hm, that bit rate is fairly tolerable for general Internet, you might even be able to get video, with enough buffering and lower resolution. We got by with 28k in my day, and Realnetworks even managed to squeeze atrociously awful video down that link!

        Nice error correction, and even handier, looks small enough that you could hide it effectively! Maybe a way of switching it on and off remotely would be good for that, too, if you wanted incognito. Something like a simple mobile phone link, with an Arduino receiving SMS messages to turn the power on and off for the whole system. So you’d switch it on just before you need it.

        Last important question would be “is it cheap”? If I needed something like this, I can imagine being quite satisfied with it.

  2. The problem I see is:

    Load a HTTPS encrypted page and/or encrypted data….
    Isn’t that a violation of the Amateur radio license?

    Though it wouldn’t hurt to seek an exception from the FCC/OFCOM/etc for use with encrypted streams under circumstances such as this one.

    1. > Load a HTTPS encrypted page and/or encrypted data….
      > Isn’t that a violation of the Amateur radio license?

      On Ham bands is a violation, with telemetry kit I do not know!

      1. I’ve forgotten the UK band about if it is the 800Mhz or 900Mhz as part of some short-range citizen broadcasting With my terminology loosely stated, because I haven’t a clue what I’m on about… Just enough to probably be dangerous if practiced.

        If I remember, said 800/900Mhz devices are used for DIY UAV with FPV. They have to be respectfully FCC and/or OFCOM certified for use in and as per their country. This should cover cryptic use to prevent danger from transmission tampering causing loss of sight and thus control of the UAV…. Something like that…

        Corrections and/or confirmations welcome…. My tea break’s over.

        1. Just to be clear, there’s an ISM allocation around 433MHz, so if you’re using it that way, encryption is fine. There’s also an ISM band around around 900MHz. That’s why you could get 900MHz wifi gear.

          1. Only if you are using ISM power levels. like 25mW EIRP.
            Above that you need a license and at least here commercial entities cannot get those for commercial use on hambands. So amateur it is and thus no crypto.
            Too bad our 868MHz ISM band has more strict power level limits than the USA 900MHz one.

    2. Thanks for pointing it out, I was going to mention the same.

      its a shame about the encryption rules, I had an idea about making a 6 meter mesh network, but those darned encryption laws…

      anyone know why these are a thing by the way? are they worried about some nefarious purposes for amateur bands? or is it just about monitoring? because the FCC very rarely monitors amateur bands any more.

  3. I just recently had a similar problem, no LOS to provide internet to an economically disadvantaged disabled person who is stuck in their home most of the time.
    I was thinking about the old barbed wire telephone party lines.
    http://gizmodo.com/barbed-wire-fences-were-an-early-diy-telephone-network-1493157700
    I wondered how I could get a good data rate using probably and arduino ‘modem’ soem big ratio transformers and I assume FSK for the same reason as DTMF on a pretty inductive line.
    I was hoping to get about 500m and maybe Mb/s speeds.
    If anyone can provide a good link to let me bypass dead ends it would be appreciated.

    1. Back in the day, in Las Vegas, when COMDEX was still called Computer Dealer Expo, the barbed wire trick was on display, thrilling attendees and slicing fingers. These days, they have groups of dancing quad copters and no Microsoft booth.. Times change.

    2. I have read about people using barbed wire fences to carry 10BaseT ethernet.
      You just either couple it to two pairs like in an ethernet cable and let TCP/IP deal with packet loss.
      SHDSL/SDSL modems could also be used to pipe internet over long distances over one or two “pairs”.

      With a single pair it’s either suitable SHDSL variant or maybe serial and SLIP.

      Wayback Cisco demonstrated ethernet over barbed wire:
      https://blogs.cisco.com/datacenter/ethernet_over_barbed_wire_arcnet_100mb_token_ring_100base_vganylan_and_iscs
      Some details:
      https://tech.slashdot.org/comments.pl?sid=25612&cid=2782849

      T1 over barbed wire:

      Other references:
      http://www.sigcon.com/Pubs/edn/SoGoodBarbedWire.htm

      Or you could acquire a ~500ft roll of fiber or telephone wire.

      1. Fibre. Or opto-isolated cable. Raw copper – bad plan unless it’s terminated to something that’s self contained and self powered such as a POE wifi access point. It might just be easier to use a long range access point tbh – something like EnGenius – will easily cover that distance over open ground. Use a repeater if necessary to get the signal indoors, depending on construction of the receiving building that might not even be required.

          1. In principle you could bounce optical off clouds or ambient structures, but you’d face huge path losses and lots of noise. So low bandwidth and a fairly powerful transmitter.

    3. simply get a pair of old used ADSL modems. they will work over dry loop dead phone wires that the phone company is not using or a run of really cheap cat3 that you can do yourself. People have used those for years now to get internet across phone lines at greater than T1 speeds without paying for the phone company T1 extortion prices.

      1. Isn’t ADSL Asynchronous by design and uses different frequency band and modulation for uplink and downlink. Not that surplus DSLAM (the other end of an ADSL line) are that costly.

        But that’s really interesting, do you have any additional details?

  4. with better radios he should be able to get more than 1KM. we were getting 2km easily with 802.11b and old discarded dish TV antennas back in the days of community internet. He should be getting 10km easily with even just a pair of cheap yagi antennas.

  5. TCP/IP & SLIP really aren’t designed for use over a non-error corrected link. I appreciate he’s got the job done, but the real answer is to implement a byte level error correction and probably also strip much of the tcp & SLIP headers to increase throughput – assuming point-to-point. It’s great fun rolling your own protocol, and much more efficient!

  6. My last successful long range WiFi deployment was only 3 city blocks. Two directional hi gain antennas, and 802.11b. I know how is that possible? Well, it worked until the trees grew another two feet taller. The main connection utilized P.O.E antenna from the roof aimed at the other P.O.E. antenna, sending and receiving across Wilshire Blvd. When the city trimmed the trees, it resumed service.

      1. Good idea, however, our main building was the big guy on the block. Not sure how the company was able to buy two locations three blocks apart, but it was a charity, so probably they were donated. And, my work was donated so when it worked, they were pleased. 802.11b never was very good at a distance..

  7. Slip is handy, not just for internet. It is a simple well understood packeting protocol. I have used it for almost 20 years to provide alightweight reliable inter microcontroller links. A CRC is a good idea.
    Slip adds, on average about 0,5 percent overhead. At worst case it doubles the data rate.

    1. Our friend Emmanuel IU8HBZ is in Italy, the land of Arduino.
      So less problems with the FCC.
      But if he used 900MHz then Autorità per le Garanzie nelle Comunicazioni would likely be pissed, as that a cellular band. Thankfully 902-928MHz is in the handset uplink band so it would not jamm cellphones that badly.

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