From what I've read as soon as the PLB is activated it begins sending out a signal that can be heard by both the GEO and LEO satellite. Since the GEO satellites are always in view, they receive the signal almost immediately without any location information. Until a GPS fix or Doppler location is available, that signal is being sent without any location information.

SARSAT's web site http://www.sarsat.noaa.gov/ says that even without a location, the initial alert gives them time to verify the alert by calling the telephone numbers given when the PLB was registered.

If the PLB has an onboard GPS it will take 1 to 16 minutes for the GPS to be able to provide a GPS location (assuming it can get a fix). Some PLB's let them obtain a GPS location from an external GPS. Once that location is available it is sent along with the PLB signal.

I always assumed that the Doppler location is something calculated by the 'system' using data from the LEO satellites. I wouldn't think that the PLB does those calculations, since it is not a receiver. At some point after the initial PLB signal is initiated that Doppler location information is provided to the Mission Control Center.

BUT I'm not an expert in all of this. I'm sure Doug can tell you exactly how it works.

I'm not sure how much time you spend out in the landscape, so I don't know if a satellite phone rental would be more cost effective. My wife and I camp in Death Valley on the occasional Thanksgiving, and we rent a satellite phone for the week we'll be out there.

Overhead canopy definitely affects reception, but that's not a problem for us in Death Valley. You'd have to know how far an opening is that the phone can see a satellite through.

We take local numbers for hospitals, ambulance, and tow trucks, as well as our Triple-A number. The nice thing about a sat phone is that you know you've gotten through and talked to someone who can help, they can stay on the line and give instructions, if need be, etc.

If you do a search for satellite phone on Google, you'll get lots of rental places, as well as places that sell them. GlobalStar has a system that appears to be failing as a result of radiation damage to the satellites. Iridium is still working. Both systems cover the US and the Caribbean.

Rentals vary all over the place in prices. Some include free shipping, some charge exorbitant amounts going and coming, but cheap rent. I always run the numbers for all the charges to see which is least expensive overall.

If you have a chance, try a rental your next landscape trip and see how it works for you, especially if you're going to be under the canopy. I'm a very happy camper in the boonies with a sat phone. Like you we haven't needed it for real emergencies, but we've helped fellow campers who've broken down and we've gotten weather reports for the Sierra Nevadas to check whether we want to come back via Reno or Barstow. Sat phones come in handy even when it's not life or death.

To KenK: I think I have a fairly good grasp on the system now thanks to you and the others here as well as studying the links provided. Thanks to all.

I am happy to report that I received the McMurdo 210 today from www.marine-electronics-unlimited.com. Free 48 hour shipping is pretty amazing.

The unit is about 1/3 the size of the MicroFix; weight difference in negligible to me. Cost is about 40%. I have read of the poor test results from Doug’s testing in 2004 but have seen no problems reported with the newer models.

The 210 allows 12 internal self tests per year and a total of 10 GPS acquisition fix tests over the five year battery life. Since the antenna can’t be deployed for testing, a ‘full circle’ test can’t be performed. Still, given the form factor and price I will receive full value until the ResQFix 100 becomes available.

I want to develop a test protocol to learn the GPS acquisition of the ACR unit in the real life conditions we encounter in the Glades. The dry season (November-May) is not so bad; the cypress loose their leaves and the prairies are mostly dry. During the wet season the cypress are in full foliage and will be a problem even in the prairies. I will need to develop techniques/tools to get the PLB into position to see the sky. The boat BlackFly offers a different set of challenges with the mangroves.

Will be a fun project while Angie is working with her gear.

Thanks to all for helping me get this gear in my kit..

Hey Phillip,

Thanks for the tip on the sat phone; I’ll definitely look into it.

Rental won’t work as we are weather driven and seldom know which direction we’re going until we see the morning sky. But it sure would be nice to always have voice capability. Not sure if ownership of a totally waterproof unit would be cost effective, but definitely worth looking into.

Thanks!

First, CONGRATULATIONS on a great new toy. Its too bad you can't "play" with it more, eh?? My family bought ours because we thought it to be a relatively small price to pay for the safety it brought us when heading out into less traveled areas.

From looking at the Fast Find manual on-line, it looks like you should be able to get a good test of the GPS right though the yellow cover. The GPS antenna is underneath the "GPS Zone" label shown in the manual, and being plastic the yellow cover shouldn't really interfere with the GPS signal.

One note - the McMurdo FastFind manual is so much nicer than the manual that came with my ACR TerraFix. I would have thought ACR could have spent a little more money on providing a good manual with photos and at least better diagrams.

I would REALLY like to know if the GPS chip set in the FastFind is one of the older ones or one of the newer high-sensitivity ones. I can't find any info on that in either Doug's write-up or on McMurdo's web site. I would hope it is a newer one since they can obtain GPS fixes under amazingly poor conditions (fairly often my Garmin GPSMAP 60CSx can get a fix from the center of the first floor of my house - amazing.

Bit tied up with Knife Rights right now, We have done some preliminary testing of the GPS in the new Fast Find last week and I'll have results to post next week or so. It is a new multi-channel chip.

Here’s an update since testing my new McMurdo Fast Find PLB:

I took the unit over to my friend’s house to show it off. He was impressed. I wanted to do a self test and a GPS test with him watching to verify I did everything right as well as observe the results.

We took the device to his dock behind the house for the test. The house obstructed the sky at about a 45 degree angle to the west while the rest of the view was obstructed to about 20 degrees.

We also had a Garmin GPS-12 (older chip set) to turn on simultaneously to see where the birds were and compare acquisition times.

The self test was simple with a pass. We did not realize at first that the GPS test had to concurrent with the self test so we had to restart from the beginning. The second self test passed as well and I put the unit in GPS test mode while he turned on the Garmin. We watched the Garmin find then acquire the first three birds in about a minute. A few seconds later the Fast Find signaled that it had acquired a GPS fix.

I am very pleased with the results. Of course, this is just a couple of guys fooling around in the back yard, not a scientific test or adverse conditions. I’m anxious to see the results of Doug’s testing.