Ham Radio WiFi

Many Ham Radio operators in the United States participate in Field Day. This is an annual exercise where radio operators are encouraged to set up stations in conditions that might occur after a natural disaster. Usually, this means taking over some park or camp site, bringing generators, portable equipment, and making it all work for the weekend before you tear it back down.

It isn’t much of a Field Day without electricity. That’s why most stations use a generator, solar cells, or even batteries. Today, though, you probably need an Internet-connected computer to do logging and other features. [HamRadioConcepts] has a video (see below) that shows how they grabbed Internet from a distance for their Field Day site.

The key that made it possible is the fact that most cable companies now broadcast public WiFi hotspots from residential and commercial routers. You usually need to opt out of this and most people don’t. If you have home Internet through that provider, you can usually use these hot spots for free.

In this case, there was no hotspot in range, but across the lake there were several. Using a dish and a 1 Watt USB network adapter, they were able to get on computer on the network and then use connection sharing to propagate the WiFi around the Field Day site.

If you prefer to roll your own antenna, we can help especially if you have a wire mesh spoon.

20 thoughts on “Ham Radio WiFi

  1. I used to use old sat tv dishes with a bow tie antenna at the feed point to get numerous km for wifi connections. Worked great until trees grew up and blocked the path

  2. I’ve seen a number of implementations of ham radio wifi including a link between 20 mile distant repeaters on 5 GHz, but this might just be cooler than all of those because of the “hackyness” of it. Well done!

  3. Seems those antennas are way overkill for for the purpose it’s good to test equipment but now your transmission (EIRP) power is far stronger then it needs to be (assuming the power output on the ap is set to default). Also sometimes using a high gain directional antenna can hurt your noise floor in some situations.

    1. I don’t see how having too much antenna gain could hurt your signal/noise ratio. Antennas are linear devices, so while yes, it will pick up more noise, but the signal increases proportionately. The goal of high-gain antennas is to provide enough signal amplitude that receiver front-end noise becomes insignificant. If you have too much signal, well, that’s easy to fix.

      1. For outdoor antennas more gain is (almost) always better. For indoor operation the SNR can indeed be reduced, since a significant part of the signal power may be delivered via reflections instead of the direct path. OFDM radios don’t care that much about multipath (as long as the path delay is less than the CP length), but by using the directional antenna you may be throwing away useful signal energy.

  4. The antenna alone with a dongle would have been enough across that pond. In the video I thought it was a creek or river. No extra power amp needed. Always use the lowest power you can to get through.

  5. You don’t mention some important things.
    Hams can create Wifi networks called HAMNET (in Europe), it is not visible using off the shelf equipment. You must feed some routers with alternative software that enables them to use 10Mhz bandwidth only.
    With that modification HAMs can use much more power on transmitting (according to license).

  6. Do not have to buy an antenna, kind of sad hams did that. Grab an old sat dish antenna and build a simple biquad to sit at the feedpoint and then point it.

    http://www.instructables.com/id/Bi-Quad-WiFi-Antenna/

    I have seen a standard eastern arc Dish network dish with one of these pull in signals way better than that cheapie TP link antenna. I am trying to get photos of what a group of hams did up in northern michigan with a 10′ old C band dish and one of these biquads to get wifi across the straits of Mackinaw for field day use.

    1. And they probably should have built the computers they were logging with also. I suppose if they had more than just a day to set up they could have even cut the trees and built the tables and chairs that they used to sit in. But the point of Field Day is much smaller than all of that.

      I wonder why you weren’t out there dispensing your know-it-all for them? Your esteemed wisdom and antenna moxie could have saved them lots of embarrassment.

  7. Nobody else noticed that despite the assertion at the begining and end of the video this was not in fact legal?

    It is true that in the US WiFi bands are shared with amateur radio bands. It is also true that a ham may repurpose WiFi gear for amateur use and even get to use a higher output power. Using that higher output power however means that the amateur must comply with all of the part 97 (amateur radio) rules rather than part 15 (unlicensed) rules that normally cover WiFi. That opens these users up to 2 issues that I am sure about, maybe a 3rd too.

    – Part 97 does not allow for encryption. That link was using WPA2.
    – Part 97 requires the amateur to identify themselves with their callsigns at least every 10 minutes. Usually when hams use wifi gear as ham radio they make the SSID their callsign.

    I would imagine that these two rules would make it impossible to connect to an Xfinity hotspot. Can the SSID be changed and encryption turned off?

    – Also I’m not 100% sure about this but I don’t think stations operating under parts 97 and 15 are allowed to communicate with one another. Maybe somebody can confirm or deny this for me.

    It might be possible to legally get internet access. If they talked to the owners of one of the homes they might have been able to set up a non-encrypted gateway with the club callsign as SSID not unlike how they shared the connection among their camp.

    Even so most ham wifi networks do not include internet access for a reason. As soon as somebody uses any encryption they are no longer legal. That means no webpages via https. I supose you can check your email but the password, messages and everything have to be sent in the clear, not a good idea. Also, don’t even think about checking your work email as you have a pecuniary interest in that making it also illegal over part 97.

    Some might point out that he probably could have done this with an ordinary lower power dongle. If he had to use any kind of aftermarket antenna with higher gain than the original or even mount the dongle with it’s stock antenna in a reflector that would still be breaking part15 rules so they would still need to operate under part 97.

    Honestly I don’t mean to spoil anybody’s fun by posting this. I really do wish there was a part15 band that allowed greater distances. I also actually like to read about WiFi hacks assuming they aren’t interfering with anybody. Hams are usually pretty big sticklers about the rules because we don’t want the FCC to ever see us as a hassle as then we would likely start losing privileges. Also, from the video it sounds like they really don’t already know this and might like to know especially since they already posted their video for the world to see.

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