Update on my 915mhz tests

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  • Sinksalot
    Commander
    • Mar 2020
    • 332

    Update on my 915mhz tests

    Ok here is an update. I been looking into 915mhz. Some people have heard of some guys using 433mhz and 915mhz years ago on their subs, but no one really paid much a attention to them as 75mhz ruled. However after talking to a few people who used older 915mhz radios and upgraded to the better 915mhz ExpressLRS and TBS crossfire radio systems. I must say, I know why they went with the newer 915mhz systems. These new system have better signal correction and power for super long range flying. When using this radio system its very close to using a 75mhz radio in a sub. I install the receiver in my Thunder tiger Neptune sub and took it to the lake. I drove it around and when was in clearer water I dove the sub down to 3 feet then walk about 100 feet away and controlled the sub to surface and it did. Most of the time when I could see it the sub I was 1 to 2 feet down cruising around. I had full control of the sub at all times So was I surprised yes. Please note the transmitter, the 915mhz module and receiver were made last year and bought new off Amazon and a Drone hobby shop and required no soldering to the receiver.​
    Last edited by Sinksalot; 01-28-2023, 08:35 PM.
  • Sinksalot
    Commander
    • Mar 2020
    • 332

    #2
    Next thing is to see if the telemetry will work under water. I first need to get addon or make my own addon.​ However this is just a bonus, I really dont need it

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    • trout
      Admiral
      • Jul 2011
      • 3545

      #3
      this is great news..... For those like me, do you have photos and parts list?
      If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.

      Comment

      • Sinksalot
        Commander
        • Mar 2020
        • 332

        #4
        Originally posted by trout
        this is great news..... For those like me, do you have photos and parts list?
        Well right now if you don't want to do any soldering and just want to put it in your sub like a reg 75mhz system and just set the setting on the radio, It will cost you around $323 for the Transmitter, 915mhz module and receiver, without tax of course. As I said before , Amazon or drone hobby shops sells the stuff As I like I like a big screen and a ton of other stuff that a RC sub doesn't really need I went with a transmitter that was a higher price and with a 915mhz module that was the most power for the 915mhz TBS Crossfire module It can pump out 2000mw of power, however it is a overkill. A module that does 1000mw is fine and a hell of a cheaper, that is why my system ended up costing $553 a lot of needless overkill.

        I am using a Radiomaster TX16S transmitter with a 915mhz TBS Crossfire Transmitter Module and a TBS Crossfire 8 Channel Diversity Receiver. Below are pictures of what I bought and worked in my sub, but both the transmitter and the module I bought are overkill.

        The better and cheaper options I think would be a Radiomaster Boxer or Radiomaster Zorro transmitters and 915mhz TBS Crossfire module that fits one of those Transmitters. However I have not tested those, other sub people have. Also don't just buy stuff, make sure your buying the correct stuff as don't confuse 915mhz stuff with 2.4ghz stuff as the packaging looks the same.



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        • Sinksalot
          Commander
          • Mar 2020
          • 332

          #5
          Also please don't buy anything yet. Yes it works, but I want to figure out the receiver fail safes and make sure they work. Also want to figure out which Antenna option is the best.

          Comment

          • Sinksalot
            Commander
            • Mar 2020
            • 332

            #6
            I was testing a prebuilt 915mhz 8 channel receiver in the lake and it worked good the other week. I now bought another TBS crossfire 915mhz receiver and bought a daughter board for the receiver that can send the Battery voltage and other stuff thru the receiver to the transmitter.​ Next test will be to take the Sub down to the lake again to see if i still get the Sub battery voltage when the Sub is 2 feet down. Here is a picture of the Transmitter showing the RX voltage being sent to it from the RX..​ I also added the three TBS Crossfire receivers I am testing for sub use below.

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            Last edited by Sinksalot; 02-07-2023, 04:58 PM.

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