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Difference between MB levels and Gradient Factors
- Thread starter SeanW
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i Switched because I got a great deal on a HUD which I’ve wanted to try for a long time and picked up a G2 here to have something to look at while I try to break my habit of looking at my wrist
I find the logging on log track a bit (huge bit) light over the shearwater logging app so I’ll just have to make constant observations during the dive so this will be Rogan science, no data just opinion.
it does calculate RMV and psi per minute
i dont have the chest strap so it has decided my heart rate to be 255 BPM
but the good news it it calculated me to have burned 8k calories for an 83 minute dive I rarely ever look at the logs and this SP system is pretty odd compared to SW.
Can’t speak for SW logging, but via logtrak SP logs are vague, useless pieces of hot turd; but when importing into Subsurface they are quite decenti Switched because I got a great deal on a HUD which I’ve wanted to try for a long time and picked up a G2 here to have something to look at while I try to break my habit of looking at my wrist
I find the logging on log track a bit (huge bit) light over the shearwater logging app so I’ll just have to make constant observations during the dive so this will be Rogan science, no data just opinion.
it does calculate RMV and psi per minute
i dont have the chest strap so it has decided my heart rate to be 255 BPM
I rarely ever look at the logs and this SP system is pretty odd compared to SW.
255! I can make an engineering guess to how that happened, but it’s both demeaning and flat out funny (to me at least):
255 is the biggest of 8 bits; but to denote / guard against an overflow in calculations on a floating point capable processor (involving -ve values) the max bit value is denoted as equivalent to -1: meaning either invalid or the we actually use -ve values (not HR obv)
It’s trying to tell you -1 but the graphical interface can’t display that
Was that the HID or a wrist G2? And which firmware do you have?
Mine (G2 wrist, got no xhest strap) simply gives me a „—„ at HR
This was the HUD, I haven used the G2 yet, HUD is using whatever the newest firmware is, 1.5 I think.Can’t speak for SW logging, but via logtrak SP logs are vague, useless pieces of hot turd; but when importing into Subsurface they are quite decent
255! I can make an engineering guess to how that happened, but it’s both demeaning and flat out funny (to me at least):
255 is the biggest of 8 bits; but to denote / guard against an overflow in calculations on a floating point capable processor (involving -ve values) the max bit value is denoted as equivalent to -1: meaning either invalid or the we actually use -ve values (not HR obv)
It’s trying to tell you -1 but the graphical interface can’t display that
Was that the HID or a wrist G2? And which firmware do you have?
Mine (G2 wrist, got no xhest strap) simply gives me a „—„ at HR
Since computers use a formula, no matter which they choose, not actual physical blood chemistry it all something of a crap shoot. Conservatism is all about comfort level while riding the sharp edge of Deco.
i had a friend get bent on a fairly benign dive at Truk, she was using a Suunto it called for deco (the rest of us on SP Luna and a Sol) she did the deco as called for by the much more conservative Suunto and got bent, turned out to be a PFO, even the most conservative computer can’t account for such things.
now I’ve done two common easy dives this last weekend with my SP HUD of GF (40/80) and used the G2 on MB (only algorithm on this unit) L2 and did Periodic NDL checks and what I saw was the MB ran 20 to 50% more conservative on NDL, second dive dive I switched the G2 to L1 and it seems to throw a heavier weight toward repetitive dives and was always about 40 to 60% shorter on NDL yet still nothing to worry about.
overall I don’t think it matters for regular old recreational diving, if you are doing agressive rec the GF is easier to work with and is a better tool and better for planing, even the newer SP stuff is coming with both, even the biggest elephant/sloth can turn toward the more popular path.
im starting to like the HUD, navigation is so nice with it. Next dives will be L1 and maybe switch to L0 for the second.
it really seems the difference between MB and GF is nannyism but it’s not really to bad, sort of like your mom telling you to be safe as you head out for a party, the admonition is there but you have to decide what to do but to many bad choices and the SP mom will ground you for a day or two.
i had a friend get bent on a fairly benign dive at Truk, she was using a Suunto it called for deco (the rest of us on SP Luna and a Sol) she did the deco as called for by the much more conservative Suunto and got bent, turned out to be a PFO, even the most conservative computer can’t account for such things.
now I’ve done two common easy dives this last weekend with my SP HUD of GF (40/80) and used the G2 on MB (only algorithm on this unit) L2 and did Periodic NDL checks and what I saw was the MB ran 20 to 50% more conservative on NDL, second dive dive I switched the G2 to L1 and it seems to throw a heavier weight toward repetitive dives and was always about 40 to 60% shorter on NDL yet still nothing to worry about.
overall I don’t think it matters for regular old recreational diving, if you are doing agressive rec the GF is easier to work with and is a better tool and better for planing, even the newer SP stuff is coming with both, even the biggest elephant/sloth can turn toward the more popular path.
im starting to like the HUD, navigation is so nice with it. Next dives will be L1 and maybe switch to L0 for the second.
it really seems the difference between MB and GF is nannyism but it’s not really to bad, sort of like your mom telling you to be safe as you head out for a party, the admonition is there but you have to decide what to do but to many bad choices and the SP mom will ground you for a day or two.
If the sample of divers and caisson workers from whom the M-values were derived was representative of the general diver population, in particular: had the same 25% incidence of PFO as we do, then the PFO is, in fact, accounted for in every dive computer.
Either that, or the sample was not representative, all the M-values are full of crap, we all get bent left and right.
We all have varying tolerance, there must be a lot of fudge factor in the programs but it’s still up to us on how far along the blade we want to slide. I started diving befor computers were common, never been bent but I find them very handy/comforting to use even the worst computer out there is better than none.
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