Oxygen clean MH8A transmitters (Shearwater compatible) with different transmit intervals

[KenGordon]

Nope, just recently started learning to dive a JJ with a DSV.
This was recommended by my instructor as an easier way to check pressures. The SPG configuration in the JJ is not really a convenient one. I already have the Perdix AI which I use as secondary anyway.
I can see this whole idea is opening a whole can of worms, but with my very limited experience I will trust my instructor and try it. At least it will give me one more blinking warning if I end up diving with my oxygen valve closed or running out of oxygen.

I hope we can keep this thread discussing transmitter related issues, instead of going into DSV/BOV debate or general wireless AI trashing. If you want to add something related to those issues, I really do appreciate if you PM me or start another thread.

I only get the SPGs out if I think I have run out and it is kind of unexpected. If you think you need to know then you can route them over your shoulders, like on an Inspiration, but then they get in the way and are annoying. You have stacks of gas. If you run out of dil you can plug the bailout into the manual add and ascend, if you run out of o2 you can go semi closed, bail out or plug shallow bailout into the manual add (and ascend).

Running out of gas on a rebreather is not an emergency like running out OC.

The DS4s only have one HP port, so either you do something extra evil or you loose the actual SPGs. Is that a good trade? Space down there is a bit tight too.

If your o2 is off then you know because the manual add doesn’t work, also your ppO2 will not track the setpoint and the solenoid will be clicking more than usual. The spg is not involved with knowing if you have o2 available.

JJs are born perfect, there is no need to mess them up.

 

[JohnnyC]

I don't even bother running SPG's on my rebreather bottles if I'm running 3L's. Pressure gets checked when gas gets analyzed and when you're out of gas it's apparent. Bailout gets plugged in from offboard if I need it. I've never needed it, but the option is good to have for a number of other reasons.

 

[taimen]

If your o2 is off then you know because the manual add doesn’t work, also your ppO2 will not track the setpoint and the solenoid will be clicking more than usual. The spg is not involved with knowing if you have o2 available.

I can see all these arguments also supporting the wireless SPG, possibly even removing the actual SPG to remove clutter (as it is not as critical). While JJ's are born perfect, that SPG routing takes some faith
I know many people dive rebreathers without SPG:s. Curiously, my instructor has taken a stance towards rigging wireless AI with a HP port splitter along with the original SPG, thinking that it is a good trade between evil extra o-rings, awareness and reduced problem solving time.

 

[taimen]

Thanks for finding that info. I need an o2 one for my breather. Oceanic sells black, green, and yellow. Do you know if the yellow and green are both good for o2?

The manual I quoted mentions different transmitter colors elsewhere. That and the wording I quoted suggests that all colors are O2 compatible.

 

[KenGordon]

I can see all these arguments also supporting the wireless SPG, possibly even removing the actual SPG to remove clutter (as it is not as critical). While JJ's are born perfect, that SPG routing takes some faith
I know many people dive rebreathers without SPG:s. Curiously, my instructor has taken a stance towards rigging wireless AI with a HP port splitter along with the original SPG, thinking that it is a good trade between evil extra o-rings, awareness and reduced problem solving time.

I find that the space down there is a bit tight. Maybe having the HP side rearranged will help but as it is the position of the cylinder is constrained by the way the hoses go round the stand. I try to have the cylinders quite high for trim. An extra thing there might make that harder (or easier - it would depend).

Let us know how it goes.