Does everyone really need an SPG? (w/transmitter)

[Barmaglot]

I had a weird failure with my transmitter on a recent dive - it was fine as I was setting up my gear, but after I splashed down and submerged, it did not do any updates - just stayed at 217 bar through the whole dive. I had a backup SPG on my regulator, so I used it for that dive - no big deal. After I got back on the boat, I closed the tank valve and purged the regulator to get it to shut down, then reopened the tank valve and it was still sending 217 bar. I had a spare CR2 battery with me, so I swapped it, and afterwards it worked without issues.
I have noticed, however, that while my SPG and transmitter readings match one another on the upper end of the scale, the gauge consistently reads ~10 bar more when I reach low pressures, i.e. I would see 30 bar on the computer but 40-ish bar on the gauge.

 

[DiveClimbRide]

Guages have lower accuracy towards the bottom of the scale. The computer is probably correct.

 

[Divrtim]

I've always had/carry an SPG. I've been diving computers of some sort for over 25 years. The main reason I have an SPG( located on my left side, on a 22" HP hose, with a clip and attached to my BC D ring. The clip is attached to the SPG hose with a large O ring doubled over slid through the clip ring and slid over the SPG hose.
I know some divers use bungee or cotton line cord to secure their clip to their hose. I use the big doubled over O ring because I can break the SPG free of the clip with one hand if if the hose ever gets tangled or clip malfunctions.
I've not experienced a transmitter failure per se but, I have experienced an intermittent signal loss a couple of times inside wrecks. I can see the SPG easily and it is a simple tool. Nothing really to break on it. Don't skip the deco stops.

 

[Centrals]

Guages have lower accuracy towards the bottom of the scale. The computer is probably correct.

Probably.
But does it matter?

 

[Blackcrusader]

Probably.
But does it matter?

Of course it matters. Divers have had OOA situations with gauges reading 30 or 40 bar.

 

[SlugLife]

I don't have transmitters or computer that can connect to one, so my opinion doesn't really count yet. I also didn't read the entire thread.

However, one of those $15 button SPGs would take up practically no space, and be potentially useful in some rare circumstances, if you're diving sidemount. With backmount, the button-gauge (without a hose) would be useless, because the time and effort spent removing your harness to look at the gauge would be better spent returning to the surface.

The button SPG could also be useful when setting up gear and verifying you have a full tank, without turning on and connecting the computer to the transmitter.

 

[flyboy08]

If risk adverse backups are good . 737s will fly on one engine..

 

[Colliam7]

IThe main reason I have an SPG( located on my left side, on a 22" HP hose, with a clip and attached to my BC D ring. The clip is attached to the SPG hose with a large O ring doubled over slid through the clip ring and slid over the SPG hose.

I do exactly the same thing in recreational diving. SPG is easy to see/read, the O-ring will easily break away if needed (and therefore periodcially needs to be replaced).

I've not experienced a transmitter failure per se but, I have experienced an intermittent signal loss a couple of times inside wrecks.

Guages have lower accuracy towards the bottom of the scale. The computer is probably correct.

I have intermittent signal loss, usually at lower pressures (~700psi), with my transmitter/computer unit. I have had 'failure to sync' experiences on several occassions. I consider my brass and glass SPG to be more reliable. Yes, a digital device is probably more precise than an analog unit. But, also remember that there is a mechanical / analog transducer, between the cylinder gas and the digital board, that converts pressure to a digital signal, and that unit is not necessarily any more reliable, or accurate, than a Bourdon tube.

I love the convenience of wireless air integration. All I have to do is rotate my wrist to read my computer display. I do not consider either my analog pressure gauge or my transmitter/computer unit to be absoltuely fail safe. Personally, I am more comfortable with the reliability of the SPG.

 

[tursiops]

I have intermittent signal loss, usually at lower pressures (~700psi), with my transmitter/computer unit.

What brand?

 

[Centrals]

Of course it matters. Divers have had OOA situations with gauges reading 30 or 40 bar.

You are NOT saying every spg is NOT accurate!!
So all the divers who are using spg are risking their lives! LOL.
I have not came across any rental equipment using anything other than spg in all the places that I had been diving!
Perhaps you have seen it everywhere in SE Asia! Could you name the operators please?