Shearwater Owners with AI, do you dive with a SPG?

[Divin'Papaw]

Just like when I used to use just an SPG and didn't dive with two SPGs, I have dropped my SPG since moving to my Shearwater AI computer. One pressure measuring device is adequate.

Do be sure and track your transmitter battery usage and change the transmitter battery at or before the projected life of the battery. I change mine well before.

 

[Belzelbub]

Just like when I used to use just an SPG and didn't dive with two SPGs, I have dropped my SPG since moving to my Shearwater AI computer. One pressure measuring device is adequate.

Exactly. I bring my SPGs along on a dive trip, but they stay in the boat with the rest of my SAD kit. My first DC was actually an AI console. At the time, my regulator only had one HP port, so just removed the SPG and installed the DC. When I went to wrist mount AI, I stuck with that process, even though my regulator had 2 HP ports.

I've found that my PPS transmitters have been very reliable. Haven't noticed lost comms during a dive ever. I think early on, my log showed a few seconds of no Comms, but switching the. transmitter to the same side as my DC fixed that.

 

[tursiops]

Do be sure and track your transmitter battery usage and change the transmitter battery at or before the projected life of the battery

The PPS and Shearwater transmitters (MH8A coding) send a code in each transmission with battery status (GOOD, LOW, CRITICAL). Some computers display this (eg Shearwater), some don't (eg Oceanic).
The transmission is coded like this:

Reading Wireless Air Transmitter using Arduino

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If your computer shows LOW then change the battery in the transmitter; you can finish the dive but don't push it for another dive.

 

[amado_sarhan]

I recently asked this question and I recently purchased new computers to enable the use of transmitters. After around 20 dives, I realised I don't need redundancy when it comes to gas reading. If I only have transmitter(s), and it(they) fails, I will end the dive. If I have an SPG, and it fails, I will end the dive. If I have both, and one fails, I will end the dive.

I look forward to what Garmin Mk3 brings forward in terms of transmitter technology.

 

[Belzelbub]

The PPS and Shearwater transmitters (MH8A coding) send a code in each transmission with battery status (GOOD, LOW, CRITICAL). Some computers display this (eg Shearwater), some don't (eg Oceanic).

Do you mean in the downloaded log, or on the computer display? I'll have to double check some of my old Oceanic logs, but I believe you are correct that transmitter battery status is not included in the log. However, at least with the VT4.1, you could actually check transmitter battery status by accessing through the Menu. I don't know if it shows a battery warning during the dive, though.

 

[Wibble]

• Dive with AI on my rebreather (yellow and grey transmitters) for the past 4 seasons, about 300 hours
• Don't use an SPG -- that was the point of using AI, to get rid of clutter and danglies.
• Have never had any problems.
• Batteries replaced once per year.

Tip: make sure you depressurise the cylinders when out of the water as the transmitters will be consuming the battery

 

[hilljo88]

The SPG I would check is mounted on my buddy's rig.

 

[Dann-Oh]

I do have a Perdix AI. I dive AI on my sidemount kit. I dive SPG on my backmount kit.

I'm also a DM who regularly dives with students so I like to model good gas monitoring practices when in front of the students, plus I don't like to put my transmitters in the high chlorine pools.

 

[Fastmarc]

I recently asked this question and I recently purchased new computers to enable the use of transmitters. After around 20 dives, I realised I don't need redundancy when it comes to gas reading. If I only have transmitter(s), and it(they) fails, I will end the dive. If I have an SPG, and it fails, I will end the dive. If I have both, and one fails, I will end the dive.

I look forward to what Garmin Mk3 brings forward in terms of transmitter technology.

Why would you end your dive if the AI fails, but you still have a SPG?

 

[tursiops]

Do you mean in the downloaded log, or on the computer display? I'll have to double check some of my old Oceanic logs, but I believe you are correct that transmitter battery status is not included in the log. However, at least with the VT4.1, you could actually check transmitter battery status by accessing through the Menu. I don't know if it shows a battery warning during the dive, though.

As far as I know, on the Oceanic (at least my OC1) the TMT status is not in the LOG and not available during a dive. So you check the status before a dive, and again after if you are concerned.