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RE: [RC] [RC] Forerunner 301 Review - Mike SofenI've been using the Forerunner 201 for a few months. It is the same exact product as the 301, but without the heartrate function. I'm in the foothills of the Sierras in California, lot's of trees and undergrowth and canyons. It is far more reliable (reception-wise) than any previous GPS I've used, and the rechargeable batteries last nearly 15 hours. If I ride into a canyon, the signal is maintained for a while, then drops out. It assumes I maintain the same pace, and that the trail is fairly straight, so that when I again get a signal, it extrapolates the distance from the prior point of lost contact. In one stretch I lose the signal for about three miles and it showed 2 miles...so it isn't perfect when extrapolating, but at least it doesn't just give up like prior models did. I'm extremely pleased with the product. I use none of the bells and whistles. I only want to know how fast am I going right now, what is my average speed for this loop (or trail segment), what is my loop time and overall time. Mike -----Original Message----- From: ridecamp-owner@xxxxxxxxxxxxxxxxx [mailto:ridecamp-owner@xxxxxxxxxxxxxxxxx] On Behalf Of Truman Prevatt Sent: Friday, March 11, 2005 6:20 AM To: April Cc: Ridecamp Subject: Re: [RC] [RC] Forerunner 301 Review There are two pieces to the equation. First is the antenna gain. The second is the sensitivity of the electronics used in the receivers. The GPS signal is very weak - less than 10^-16 watts per Hz. It is well below the ambient microwave radiation background noise on the earth. It uses encoding to allow the receivers to see it. The current batch of 12 channel commerical GPS receivers are not very sensitive. Even with a optimal 1/4 wave antenna you don't get the gain you should because of the receivers. The good news is there is a trend for the use of GPS in indoor applications. Try using your GPS inside - it won't work. In order to get one that work inside you need about 100 times more signal strength delivered to the decoders (see http://www.gpsworld.com/gpsworld/article/articleDetail.jsp?id=149220 ). I expect we will see the development of affordable high gain antennas and more senitive receiver technology in the near future, and with Gallieo (Eurpoean navagational satellite system) coming on line and receivers designed to use both systems. These advances will eventually filter down into the inexpensive commerical outdoor units and solve many of the problems the current crop has. But currently with my GPS I don't even think about messing with it in the forest when the foliage is out - it can process the signal. Truman April wrote: This is true of any GPS unit and it not a problem specific to the Forerunner. I haves not had a moment's trouble with satellite reception when not in the woods (i.e., riding along the roadside), so I have not experienced "marginal" results in that instance. When I am going to be in an area that I know (or think) will have problems with satellite reception, I also use an external antenna that works in most of the conditions I have had it in. There is a runner in NC that uses an external antenna with great success in areas that he couldn't pick up a signal without the external antenna. http://www.pc-mobile.net/gpsant.htm BTW, even if there is no satellite reception, the 301 will still record heart rate data. April Nashville, TN -- "It doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiment, it's wrong" Richard Feynman =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Ridecamp is a service of Endurance Net, http://www.endurance.net. Information, Policy, Disclaimer: http://www.endurance.net/Ridecamp Subscribe/Unsubscribe http://www.endurance.net/ridecamp/logon.asp Ride Long and Ride Safe!! =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Ridecamp is a service of Endurance Net, http://www.endurance.net. Information, Policy, Disclaimer: http://www.endurance.net/Ridecamp Subscribe/Unsubscribe http://www.endurance.net/ridecamp/logon.asp Ride Long and Ride Safe!! =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
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