• Welcome to ScubaBoard


  1. Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

    Benefits of registering include

    • Ability to post and comment on topics and discussions.
    • A Free photo gallery to share your dive photos with the world.
    • You can make this box go away

    Joining is quick and easy. Login or Register now by clicking on the button

Using 2 transmitter on one computer

Discussion in 'Computers, Gauges, Watches and Analyzers' started by Magnus Lundstedt, Nov 26, 2018.

  1. jgttrey

    jgttrey Nassau Grouper

    # of Dives: 200 - 499
    Location: Houston
    149
    93
    28
    I would not get too balled up about GTR function. I just don't think it offers much utility.

    If you think about it, technical/advanced divers don't need GTR calculations on their computer to figure it out, and should have planned all that in advance. They understand their consumption rate and effect of depth (and hopefully have enough gas that what is really limiting the dive is the dive plan/deco anyway) and turn the dive when they hit their planned turn pressure.

    Less experienced divers, on the other hand, who might "benefit" from a GTR calculation because they don't do that kind of planning might be inclined to put too much faith in it. It's usually just a snapshot based on the last 90 seconds or something of tank pressure change. It would be worse than useless if you had an issue, went deeper, etc.. Your 20 minutes of GTR will turn into 3 minutes in a panic. I think it can breed a false sense of security. GTR is not a guarantee and I'm not sure some divers understand that.
     
    Coztick likes this.
  2. BurhanMuntasser

    BurhanMuntasser Dive Charter

    # of Dives: I'm a Fish!
    Location: Nomad
    4,778
    1,340
    113
    I am not certain if it would display both at the same time, I haven't used my computer for SM and the watch computer that can do SM was announced at DEMA and I haven't had it in my hand yet. It is worth asking them.
     
  3. Mike1967

    Mike1967 Nassau Grouper

    # of Dives: 25 - 49
    Location: Australia
    150
    49
    28
    Agreed, I'm only just starting to get into SM/tec so I really should forget about it, I guess I'm just use to it. SAC would still be handy though.
     
  4. Mike1967

    Mike1967 Nassau Grouper

    # of Dives: 25 - 49
    Location: Australia
    150
    49
    28
    From Shearwater for those who care...


    There are plans for a sidemount mode. Due to other priorities, I can't promise when exactly when it will be implemented, but it is highly requested and on our radar.

    Sorry that I can't give more details at the moment, but if you have other questions please don't hesitate to ask.

    Best,
    Tim Inglis
     
  5. BurhanMuntasser

    BurhanMuntasser Dive Charter

    # of Dives: I'm a Fish!
    Location: Nomad
    4,778
    1,340
    113

    Here is the reply from Ratio's Tech.:

    " On the main screen you can see up to 2 transmitters (the green/orange/red bars on the right are tank 1 and tank 2).

    By pressing the bottom right button you have the possibility to see all the transmitters."

    As I said, it has it all :)
     
    stuartv likes this.
  6. kelemvor

    kelemvor Big Fleshy Monster ScubaBoard Supporter

    # of Dives: 100 - 199
    Location: Largo, FL USA
    5,038
    2,452
    113
    The old scubapro galileo (luna or sol) can display pressure from two transmitters at a time. I use the feature when I dive with my wife, eliminates the need to query/respond to each other about gas levels.

    I think there's a multi gas software upgrade you can buy for it that allows pairing of more transmitters... but I wouldn't want to do any kind of technical diving with a Galileo.
     
  7. stuartv

    stuartv Seeking the Light

    # of Dives: 200 - 499
    Location: Manassas, VA
    6,907
    2,835
    113
    I am a technical diver. I do plan all that out in advance ... for technical dives. When I am doing NDL diving I do not do the same kind of formal gas planning. On those dives, it is a nice sanity check to have that GTR displayed. I.e. an easy way to confirm that my own on-the-fly calculations are correct. I have AI on my Oceanic Atom computer, as well as my Perdix AI and Teric. I have always found the GTR calculations to reasonably accurate. Certainly accurate enough to use for sanity checks on NDL dives.
     
  8. kelemvor

    kelemvor Big Fleshy Monster ScubaBoard Supporter

    # of Dives: 100 - 199
    Location: Largo, FL USA
    5,038
    2,452
    113
    I disagree. For recreational dives, it's my favorite dive computer feature. Different strokes for different folks, I guess.

    Personally, I wish I could swap the NDL field and the ATR field on my dive computer's display so that it was the big number in the middle. PSI would be pretty much as good, I guess. A DC that calculated cuft remaining would be cool. Obviously you'd have to tell it some details about your tank in advance.
     
  9. jgttrey

    jgttrey Nassau Grouper

    # of Dives: 200 - 499
    Location: Houston
    149
    93
    28
    For those that know its limitations, I have no problem with GTR for grins or sanity check or whatever. I just don't see any great advantage and I certainly would not have it as a "must have" feature. I also have 3 oceanics in the family with that feature and a bunch of shearwaters (and others) without it.

    My NDL dives are limited by either NDL, turn pressure, or when I hit rock bottom (or whatever "time to ascend" pressure you have elected to use). GTR just doesn't add anything to that and, depending on the implementation, causes other issues and potential confusion for less experienced divers.

    Oceanic, for example, calculates GTR to include a SS and get to the surface with some designated PSI remaining. When GTR is less than NDL, IIRC, the displayed time cuts to GTR, which depending on the aforementioned settings, may not be what I want it to do. I'd like to know my NDL and not have the computer hijack that information to show my GTR as my limiting factor. Much of that is configurable in menus, but that requires some advance thinking about how you want your computer to perform.

    GTR is also only as accurate to the extent the last 90 seconds, which is the sample period for Oceanic, is representative of your RMV for the remaining dive. So, if you have to swim against the current to come back to the boat, your GTR will be less than the computer predicted. On the other hand, if you are drifting back to the boat after swimming into the current, GTR calculations during the first part of the dive will understate what you have left.

    That's my qualification about GTR: most divers experienced enough to understand its limitations will not gain any material benefit other than "interesting trivia they could have done in their head" and divers not experienced enough to understand it might be tempted to rely on it without understanding its limitations.
     
  10. Mike1967

    Mike1967 Nassau Grouper

    # of Dives: 25 - 49
    Location: Australia
    150
    49
    28
    Oh so it doesn't display it in numbers only coloured bars? Good luck using that info to switch regs lol
     

Share This Page