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BOARD01977
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BOARD01977
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Last modified
8/16/2009 3:09:31 PM
Creation date
10/4/2006 7:06:03 AM
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Board Meetings
Board Meeting Date
3/20/2000
Description
OWC Section - Water Conservation Planning Program - Evaporation-Transpiration Control Demonstration Project
Board Meetings - Doc Type
Memo
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<br />\ <br /> <br />e <br /> <br />The Pager Companies Don't Care <br />To the pager companies, the ET Signal Controller looks like any other customer, so they <br />do not have any need to get too closely involved with what function the system performs. <br />Radio stations and cable TV companies are not easy to negotiate with, and tend to place a <br />high value on their transmission capabilities. They also may see the ET Controller <br />system as a way of generating income themselves. The pager based system are more of a <br />common-carrier whose only interest is in receiving their standard payment for signal <br />transmission. The type of communications required to operate the ET Signal Controller <br />is essentially the kind which pager technology was designed to fulfill, so there is no need <br />to educate or transform the paradigm of the signal carrier. <br /> <br />Disadvantages of the System <br /> <br />It Isn't Proven in Real World Conditions <br /> <br />A field study of 40 homes has been conducted in 1rvine Ranch, CA, and the results there <br />are encouraging, but the system has not been proven under mass market conditions. That <br />is the purpose of this project. There is no guarantee that the system will work as <br />anticipated by the manufacturer. <br /> <br />e <br /> <br />It Won't Turn the Clocks off in the Rain <br /> <br />The ET schedule information is being broadcast after the fact to the controllers. In effect <br />this week's ET will be controlling next weeks irrigation (or today's ET will control <br />tomorrow's irrigation). The system, then, can not easily detect and respond to short term <br />events like thunder storms or sudden cold fronts. Consequently, there may still be some <br />irrigation systems operating the day of a large rainfall. Perhaps here is where mini-clicks <br />can playa role. <br /> <br />ET isn't Perfect <br /> <br />While ET is a widely accepted and sound method for scheduling irrigation, it is difficult <br />to ever represent the many micro climates at individual sites with data from a network of <br />weather stations. Inevitably some sites will be over irrigated and others will be under <br />irrigated with this system. Hopefully, the variations between ideal operations and actual <br />operations with this system, however, should be far smaller than variations with the <br />current manual control system. <br /> <br />e <br /> <br />Conclusion <br /> <br />We have all been disappointed by irrigation controllers in the past, so why should anyone <br />consider the pain of further let-downs? The reason is that the payoff for a successful <br />system is so large that it is worth making the effort to try anything which offers a <br />reasonable chance of success. This system has been developed and patented by a <br />company which specializes in wireless communications. It has also been tested <br />successfully in Irvine by respected water management professionals. The manufacturer is <br />staking his reputation on its being ready for further field testing and he has much more to <br />lose from failure than do any of the tesI sites. <br /> <br />3 <br />
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