SignalsEverywhere: Playing Classic Games over Amateur Radio with NPR-70 TCP/IP Modems

Over on her YouTube channel SignalsEverywhere, Sarah has uploaded a new video that shows us how TCP/IP connections can be made over the amateur radio spectrum using low cost NPR-70 TCP/IP modems that operate in the 70cm amateur band at around 433 MHz.

With a TCP/IP connection available it is then possible to play games over the amateur radio bands and Sarah demonstrates this in action with some classic games like Unreal Tournament 2004, noting that the ping was about 225ms. She notes that she used a lower symbol rate to keep within the legal limits within the USA, however in other regions a higher symbol rate may be possible, resulting in better ping. She goes on to try a strategy game called OpenRA which is a bit more suited to running on low speed high latency networks, noting that the radio TCP/IP connection worked very well.

In the video Sarah also shows what the modem signal looks like on the spectrum and waterfall using SDR++.

Playing Classic Games over Amateur Radio | NPR-70 Modem TCP/IP Unreal Tournament and OpenRA

5 comments

  1. saliva ukraini

    seems like an advertisement tbhqfamalam
    fippy bippy btw, ironically i noticed theres also that problematic “master” terminology in some of the doc screenshots of the linked, ad-ridden website. “you shall not pass”, i say to this because of the absolulty unjustified price tag and bad construction quality, i mean theyr’e even using those shitty sold-on-amazon DC/DC converters 😐

    • Sarah - SignalsEverywhere

      This started as an open source project on the hackaday website, it’s someone’s passion project that was intended to be something people could build with off the shelf parts.

      Considering what it cost to purchase hardware for alternative tcp/ip communication over amateur radio the price really isn’t bad.

      I wish there were more readily available software options for doing this type of networking over radio but they’re really just isn’t at this point in time so overall I say at least in my opinion for my purposes they’re worth the money.

      • Moderated

        Comment Removed

        ADMIN NOTE: Please note that this blog is not the place to attack the presenter of the video.

        • Rob Zom

          So why aren’t you complaining about the posts of the other YouTubers who just demonstrate some signal being decoded in some software?

    • Paddy

      Full source code, Printed Circuit Board, Bill of Materials, go make your own if you do not like the price. There is even a link to the project from the above link.
      https://hackaday.io/project/16409

      But for me the data rate of 50 to 500kbps makes the hardware unappealing, but the technical design details where the (what historically would have been called “master”) controller orchestrates time slots for all subordinate devices (which is currently limited to 7 and might be expanded at some later date to 15 with software improvements). This is to avoid packet collisions (a big improvement on the older AX.25 protocol for data throughput – where a node verifies the absence of other traffic before transmitting on a shared transmission medium, if a collision occurs both transmitting nodes wait a random timeout before trying to transmit again, rinse and repeat), so Time Division Multiple Access (TDMA) should out perform AX.25 in terms of throughput. I suspect that with an insane amount of effort that the hardware could possibly be configured to use SOTDMA (as is used by AIS, a dynamic and self organising system over time and space) and the need for a central controller to orchestrate time slots would vanish as would the limit on the number of nodes.

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