Communications – Open Loop Error

I do shore support and communications for my sister Robin. She and her husband sail a boat named after our Aunt Mabel.

One of my tasks is to make sure their iridium phone is sending communications every 4 hours. This process has worked for years. It has been reliable enough to keep everybody happy.  And also to preserve the planned isolation and peacefulness of sailing offshore. In part they carry the iridium so that folks back at home won’t worry.

The Problem

The problem we faced over the last couple of days is that I stopped receiving the location reports. Now I have been doing this since we were dependent on more traditional single-side-band (SSB) radio so dropping off line is not an immediate worry for me. Stuff happens.

However, at the 24 hour mark, there was no response. So I sent a text (and was close to making a call).  I promptly received a phone call, one of low quality, but enough to confirm that all was well.

The Resolution

I also made a change to my end of the communications system. I receive the texts via e-mail. I programed my email client to echo back texts from the Mabel Rose so they will know if I received the communications. Basic radio stuff, but we had allowed ourselves to be spoiled and become complacent with the apparent reliability of our digital link.

We will see how this works out.

Communications – The Lessons

1.  Even in a cellular network texts are not intrinsically reliable as a communications method. There is no guarantee of delivery and know acknowledgement.  Who ever thought it would become so much a part of our lives.

2. Sat phones have their limits. Understanding them and addressing them with traditional radio based traditions and techniques should go a long way to mitigating the potential problems. Remember, even if the phone is okay, it is still network dependent.

3. Communications should never be open loop when the data carried is vital.

The Cost

We got lucky this time. Other than a little worry and lost sleep there was no cost.