Mesh Networking Over Ham Radio, Our OWN Emergency Backbone Network

Discussion in 'Amateur Radio News' started by KJ4YZI, Jan 2, 2018.

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  1. VE3JEC

    VE3JEC Ham Member QRZ Page

    Thanks for the link to ARDEN, i will be looking at it. I looked at and have considered the BBHN as i have the hardware, but the lack of hardware support outside a select few was a direct turn off. So much better equipment exists outside the WRT54 realm.
     
  2. K3LI

    K3LI Ham Member QRZ Page

    All this is wonderful. Wonderfully useless in a real deal emergency, no power, no water, no phone, no cell. Useless.
     
  3. K3KIC

    K3KIC Ham Member QRZ Page

    Capabilities really aren't affected much by "advances in hardware or software". It comes down to output power, receiver sensitivity, link losses, and modulation bandwidth/method which determines required SNR.
    Generally running about 30 dB EIRP on directional antennas you can go 40 kM with considerable bandwidth. Even a bit further if you limit bandwidth to a few Mb. It's more a question of what hardware is available to hobbyists at reasonable prices.

    On a major project I had the opportunity to hang a number of radios at different heights in different environments (urban and suburban) to do throughput vs distance tests. During the testing I also had several predictive propagation packages to compare. The radios were on 2.4, 5.8 GHz, and several commercial licensed bands. Any foliage will limit usable signals above 2.4 GHz to about 2000 feet and above 1 GHz to about 5000 feet.

    As to ARDEN, I do not see any specs per data throughput being applied to the project. The radios listed as supported are primarily high end commercial radios for the WiFi or WiFi like space that will run around 30 dB EIRP. They usually use the Atheros chip sets as they are the best performers and have optimized drivers.

    So a question for the participants of the thread: What type of throughput are people looking for on these links?
     
  4. K3KIC

    K3KIC Ham Member QRZ Page

    Generally on these radios if you increase the operating power above what was originally used you run the risk of violating FCC regulations and/or distorting modulation to the point of no overall gain.
    I don't know for sure what Cisco did but we (the company I worked for had multiple divisions with radios using the Atheros chip set) had a number of transmitter parameters adjusted and stored in firmware to peak the performance at the maximum intended power level. Operating above these levels would cause issues. These adjustments needed to be made by the mfg as they include output stage post amp characteristics.
     
    KC8VWM likes this.
  5. K5RWD

    K5RWD Ham Member QRZ Page

    Awesome video and dialogue. I just ordered two of the old wifi units, I'm going into this project.

    Thanks again,
     
  6. KC6ZKT

    KC6ZKT XML Subscriber QRZ Page

    Videos are OK, but some of us can read the same information much faster than watching a video. It would be nice of the QRZ article included some links to some good textual sources for the information.
    I just took one of these units out of service as my main home access point. So now I have an excuse not to get rid of it.
     
    K6CLS likes this.
  7. W4LLZ

    W4LLZ Ham Member QRZ Page

    Unfortunately you are incorrect. They power off of a 12 volt battery, requires no water, no phone, no cell tower or any type of commercial infrastructure for the mesh to function. I will say that a PC is necessary for many of the functions (services) that are used on the mesh - most at the "station" node (not the bridge nodes); however laptops can be powered off battery power as well with a simple 12 volt lighter adapter connected to the battery source which is supported by solar panel. The bridge nodes (a node that links two stations together like a repeater) requires no computer, only an antenna, battery and router. I've used mesh to do IRC Chat (w/ Mirc software) which also does high speed file transfers at internet speeds (or better). Our group has also done video chat with a couple different free software packages (Linphone & Focus Phone). We can send live video feeds from a disaster location to, say, the EOC - or send a photo(s) if needed via Mirc. With Linphone, I've taken old Iphones (thank you wife and kids for getting an upgrade so I get the old ones) and installed Linphone on them and used the Iphone (without cell service) to do video chat between phones (like video communicators on Star Trek) or to a computer. Additionally, I've taken my home internet and linked it to the mesh network to share it across the mesh to stations who did not have internet due to down power at their site. That means, they can access websites via the mesh, send email, video conference with areas outside the disaster zone all via my local internet service. The biggest downfall with the mesh however is that it requires a "true" line of sight connection to the other station(s), meaning no trees or anything in its way. A station (say a home) to a mountain top bridge node would solve many link issues within a county region. Just saying.

    I'm not an expert on this, but do have some hands on experience in getting a few things to work on the mesh. If anyone needs assistance just email me at my QRZ email. I've documented a lot of my work (for my aging brain) that I can share.
     
    KK4HPY likes this.
  8. W4LLZ

    W4LLZ Ham Member QRZ Page

    Using the "stock" power setting on the router I've made a 2 mile mesh connection, which is nothing but it was as far I could go at the time. My node had the 24db antenna connected and the other 2 stations I connected to both had the stock bunny ear antennas on their nodes (sitting on the dash of their vehicles) and I was able to do video phone chat with both stations. The antenna does the work. The antenna I used was the parabolic antenna, cost about $40. I've since picked up a omni antenna for about the same price and a used 15db beam for $10. Antennas are cheaper than a decent 2m outdoor antenna.
     
  9. W4LLZ

    W4LLZ Ham Member QRZ Page

    I got several (like 20+) from a guy on ebay for $15 each.
     
  10. K3KIC

    K3KIC Ham Member QRZ Page


    Directional antennas certainly help a lot. Not just for the obvious link gain but in many suburban or urban areas the noise energy in the 2.4 GHz band is significant. If you are fortunate enough that the link is aiming away from the worst of it you get an additional benefit. If the backdrop behind your target is heavy foliage so much the better.
     
    KK4HPY likes this.

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