Shearwater Transmitter Issues

[Capt Jim Wyatt]

If this was an ongoing issue for a few hours during a dive, there was something else happening.

Well I put new 3.2 volt batteries in before I started this thread and am going to dive this setup again tomorrow.

 

[MyBuddy]

I have two grey transmitters on my SM rig. When I got these transmitters a couple of years ago they were sold out of the yellow ones so I had to settle for two grey ones and was aware of the possible RF clashes with two like kind transmitters.
Yesterday the displays on the handset were intermittent for both transmitters. I removed both transmitter batteries and the voltage was measured at 3.0 volts and were replaced about 10 dives ago, or about 800 minutes of usage ago, or about 13 hours ago. New ones out of the pack measure at 3.2 volts. I think 3.0 volts should run these fine. ( I only use the CR2 Lithium batteries as prescribed in the user manual)

Battery warnings occur at 2.75 volts and I have seen no warnings. Battery life is predicted to be 300 hours according to the user manual.

So my thinking is that the batteries are OK. However is it possible / likely that I am getting that "Communication Collision" problem?

I turn on one tank and wait a few seconds before I turn on the other to help prevent the collision problem.

Any ideas?

I’ve had this happen 2 or 3 times when diving sidemount. The solution in and out of water is to turn off one tank, purge the reg, wait 2 minutes (Edit #2 to correct the incorrect number found on the Shearwater site: The transmitter powers off after 2 minutes with a tank pressure of less than 50psi.), and then turn the tank back on. With any luck they’ll no longer be in sync. The only way to ensure that it never happens again is to get a Swift or a green or yellow pps if you can find one. If you go for the yellow, ensure the yellow was not part of the recall.

 

[inquis]

(Edit: The transmitter powers off after 30 seconds with no pressure detected.)

Shearwater states 2 minutes.

When diving sidemount with two gray transmitters, I turn the second tank on about 2 seconds after the first based on the ~5 second nominal period.

 

[MyBuddy]

Shearwater states 2 minutes.

When diving sidemount with two gray transmitters, I turn the second tank on about 2 seconds after the first based on the ~5 second nominal period.

Shearwater also states 30 seconds. The pdf I’m linking to has images of the old style MH-8A. I think the 2 minute number is for the Swift transmitter since the 2 min link in your post has images of the Swift transmitter .

 

[inquis]

Shearwater also states 30 seconds.

The manual for my Teric -- downloaded 12/2020, prior to the release of the Swift -- states 2 minutes in the specifications and in the explanatory text.

The pdf you linked is actually inconsistent, giving 30 seconds in the explanatory text (as you depicted) and 2 minutes in the Specifications section. I wouldn't rely on that, since it may have been partially revised.

 

[MyBuddy]

The manual for my Teric -- downloaded 12/2020, prior to the release of the Swift -- states 2 minutes in the specifications and in the explanatory text.

The pdf you linked is actually inconsistent, giving 30 seconds in the explanatory text (as you depicted) and 2 minutes in the Specifications section. I wouldn't rely on that, since it may have been partially revised.

Looks like you may be right. Now I’ll have to test this tomorrow. I had no reason to question the 30 second number from Shearwater, so once I found it I stopped looking.

 

[Capt Jim Wyatt]

Thanks for all the replies. I have sent this question to Shearwater to see if they have a workaround to suggest.

 

[MyBuddy]

Thanks for all the replies. I have sent this question to Shearwater to see if they have a workaround to suggest.

Zoltar Speaks

Shearwater says buy a Swift.​

 

[gmerick]

The solution in and out of water is to turn off one tank, purge the reg, wait 2 minutes

Whether it's 30 seconds or two minutes, this may not work at depth. The transmitter measures absolute pressure like a SPG, not relative pressure. At 30 meters the pressure within the 1st stage cannot drop below 3bar.

 

[MyBuddy]

Looks like you may be right. Now I’ll have to test this tomorrow. I had no reason to question the 30 second number from Shearwater, so once I found it I stopped looking.

Tested and the 2 min number holds.

Test #1:
Charged the reg, turned off the valve
Purged the regulator and started the timer.
@ 0 min: AI pressure on Teric 0psi (Flashing red).
@ 2 min: AI pressure still at 0psi (Flashing red).
@ 2:30 min: AI pressure changed to an alternating 0psi and a yellow COMMS.
@ 3:30 min: AI pressure changed to a red flashing COMMS.

I interpret this as the transmitter shut off at 2 min. At 2:30 min the Teric is alerting that communication from the transmitter has not been received for 30 seconds. At 3:30 min the Teric is alerting that communication from the transmitter has not been received in 1 minute and stops showing a pressure.

The current Teric manual states that the 0 psi/yellow COMMS will flash for no communication for 30 - 90 seconds and after 90 seconds the red COMMS will flash.
So the 60 seconds I’m seeing above falls within but isn’t consistent with the manual.

So Test #2
Charged tank with computer near by.
Started timer and took the computer in to the next room.
@ 30 seconds: AI pressure changed to an alternating 0psi and a yellow COMMS.
@ 90 seconds: AI pressure changed to a red flashing COMMS.

90 seconds is consistent with the manual.


Conclusion:
So it seems that there is a difference between the timing of the COMMs warnings if the transmitter pressure goes to 0 for 2 min and then transmitter turns off rather than the transmitter’s signal just suddenly dropping out.

Updated Recommend Action:
If the transmitters are in conflict turn one tank off and purge the reg to less than 50 psi and wait two minutes, or to make it simple wait until that tank pressure flashes the yellow COMMS warning then turn the tank back on.