Tenacious’s Cellular System
The two previous posts by Paula And Mogford bring up leads worth pursuing. While the Coast Guard would have reviewed his onboard equipment in preparation for their search the volunteer effort might benefit from specific knowledge of the vessel’s systems.
This could be very important in regards to his cellular devices. What models he had and how they were used on the boat could have significant impact on how you analyze his Cingular records. And have a great impact on whether his phone could still be on and transmitting after 6 days.
A cellular handset has a notoriously inefficient antenna. While a C&C 40 has limited mounting options I have done many installations on similar sailboats of external antennas and linear GSM amplifiers designed to increase the range.
A complete and ongoing review should be done of his cellular network syncs for the entire US west coast. Coverage in coastal waters is very spotty north of the Channel Islands up through Washington. Southern CA has much better coverage. In spite of this there are many small localized areas where celltower orientation, altitude and geography allows you to acquire a weak signal quite far offshore. Usually too weak to complete a voice call but enough for a network sync. It is very patchy and there are no accurate footprint maps. Even Cingular engineers may not be able to fully answer this coverage question. Our habitation patterns along the central and north coasts result in poorly supported marine cellular coverage. There are some areas around coastal ports that we do know have limited offshore coverage. Any engineers or technicians in the community with pratical knowledge should consider contacting the searchers.
Given this the practical side of pursuing analysis of his cellular phone should not be understated. Except for some particular isolated sections of coast, Had the boat come inshore or traveled parallel to it, there is a fair chance even a handset phone would have passed through an area with enough field strength to sync.
More promising would be to work out, with assistance from the Cingular’s technical staff, a range offshore from a particular tower that handled a ping. For this we need to know how the phone was installed or oriented in the vessel.
The only traceable signal that might be transmitting from the boat is his cellphone. An analysis of his onboard system and particular equipment model may give some indication of how long the vessel may continue transmitting. If the vessel is still out there and has the largest battery bank commonly retrofitted into this size of sailboat, a plugged in cellphone could last for weeks. More likely, if assuming only Navigation lights and VHF were powered, the boat’s batteries may just be dying around Friday giving a cellphone its full standby time on its lithium battery through next week.
February 4th, 2007 at 6:24 am
Yes, there are RF amplifiers and external antennas available that can be used on sailboats and that can increase cellular range considerably. There are also 12 Volt adapters available to charge the cell phone, that can be used while connected to the amplifier. I have such a system on my sailboat and was using it last year while sailing along the coast. Many sailboats have several “house” batteries in parallel that creates many Amp hours of capacity.
I am not sure how we would find out about the equipment on Dr. Gray’s boat. If no one has done this yet, I will try calling the US Coast Guard Search and Rescue Center to ask.
February 4th, 2007 at 10:52 am
I concur with the several posts on the importance of getting complete data from Cingular et al on any possible electronic connections with Jim Gray’s cell phone/PDA, including synchronization data that could be useful in triangulating or estimating location even if no audio is discernable. I concur with getting full data on the entire time period 1/27/07 (a day before, for establishing baseline) through today, so the synched location of the cell phone can be tracked and mapped before, during, and after Sunday 1/28/07.
Any data around the reported 7:30pm 1/28/07 partial signal could be key, if it helped approximate the location of the cell phone/PDA in that time frame. IF the location is close(r) to shore (or even in SF Bay proper?), that could imply a number of other scenarios perhaps not yet being considered.
As to getting access to the Cingular data, if Cingular is not responsive, wouldn’t this be an appropriate request to be made by law enforcement (eg., SFPD and/or FBI)?
I think this cell data collection needs to be fast tracked, by whatever means gets results.
February 4th, 2007 at 11:52 am
If there are any of Jim’s sailing friends reading this who are familiar with Tenacious’s equipment or which marine electronics dealer he might have used, please leave some contact information.