The curious case of AI. Do you use a back up SPG while using AI?

[Tracy]

I use both, but not at the same time. Some of my rigs have spgs, some have transmitters. I switch back and forth between various kits. I don't have both on the same rig ever, seems kind of pointless?

 

[RobPNW]

On the right side- AI DC and transmitter. On the left side- non-AI B/U DC and SPG.

 

[Feye]

Use them simultaneously.

I have confidence in both the AI transmitter and SPG. However, I've encountered situations where the SPG failed (broken) and the low battery issues on the Perdix (not the transmitter itself). That's why I employ both of them as mutual backups. Anyway, SPG is good to read on boat and Perdix is good to read in water.

 

[scubadada]

I have run a SPG backup since I first started running a backup computer to my AI computer in 2010. For a variety of reasons, some my fault, I have used the SPG backup on 17 dives. I have never missed a portion of a dive or a series of dives due to any failure,

So now I dive two AI computers, an old Oceanic VT3 and a Shearwater Teric, off the same MH8A transmitter. At the Blue Hole in Belize, I lost tank pressure on both computers and used my SPG. Turned out my transmitter had blown out the high pressure relief valve and was replaced under the Oceanic replacement system of $125.

Redundacy is what you want it to be, I have no complaints.

 

[J-Vo]

I've lost 4 HP hoses in the last year and only 1 transmitter failure. That's almost enough HP hoses to pay for a transmitter. My standard config is side mount with transmitters and gauges on all stages and deco bottles.

 

[Manatee Diver]

I've lost 4 HP hoses in the last year and only 1 transmitter failure. That's almost enough HP hoses to pay for a transmitter. My standard config is side mount with transmitters and gauges on all stages and deco bottles.

I burn through at least one HP hose a year, and have to do at least one spool replacement too (which I replace the o-rings when I get home).

SM cave diving:
Backgas: AI Only
Stages: SPGs only - two reasons, first no good way of showing all four transmitters on my Teric. The second is that stages are a team resource, so I might have to hand it off to someone.

Rec BM diving:
Backgas: AI and SPG as the SPG isn't in the way.
Pony: SPG only for the same reason as cave stages.

 

[inquis]

I run transmitters on primary gas (single, doubles, or sidemount). 2 inch SPG on a stage bottle in a cave (where reading it during the dive is useful) Button gauges on deco bottles.

 

[amado_sarhan]

Two transmitters for sidemount OC cave diving, one on each tank, both going to a Perdix on each arm. For CCR, I have one in O2 and one on dil. BO has SPG. On CCR, both transmitters go to Perdix on right arm. It was already set up for transmitters from OC diving. Even though my CCR came with a Petrel 3, I never bothered to set the AI up. I prefer having transmitters on my backup computer.

Thanks for sharing. I am intrigued. I see several divers say they're using one transmitter on diluent and one for O2, thanks for sharing!

 

[amado_sarhan]

I constantly use transmitters for a sidemount, twinset and rebreather. Never backed them up with SPG’s and I never had any issues.

Thanks for sharing. May I ask how many dives have you done on transmitters?

 

[amado_sarhan]

I use both. Sometimes the air integration fails. My little SPG always works. It adds some to the kit. Having an SPG has saved a fair number of dives. It has paid for itself many times over.

Can I ask in what way did the transmitter fail?

Thanks for sharing PatW!