It would have to be a very large, very high capacity UPS, in order to handle the current the transmitters draw. This would be very expensive. Maybe you could install a battery bank with a good quality four stage charger to power the repeaters. When the power drops, since the repeaters are already running on batteries, the switchover would be seamless. Your IRLP computer could be powered with a 1500 watt or better UPS. This should allow sufficient runtime, plus the higher capacity should get you out of the cheapo consumer grade UPS category. As Eric suggests, you could plug the serial cable into the computer, and with the right software, the node could monitor the battery voltage when it is running on the UPS, then shut the computer down gracefully if the voltage drops too low. Richard <http://www.n7tgb.net/> www.n7tgb.net
_____ From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of Eric M. Sent: Sunday, July 13, 2008 9:25 PM To: [email protected] Subject: Re: [Repeater-Builder] Switching a Repeater Betwen AC Sources Why not use a UPS? Plug the repeater and equipment into the UPS and then plug the UPS into the receptacle of choice. Might be cheaper and easier to do this then to design, test, get permission from the hospital to install, install it and maintain it. I am sure that the hospital is going to want to make sure what you install is approved for such use. Some ups's provide a serial port for communication to a serial device, maybe you can access it remotely via packet to check status, logs and battery condition. Eric. Laryn Lohman wrote: We have two repeaters, plus an IRLP computer, on one emergency-fed circuit at a hospital. There are normally no problems with this. During a recent storm, the AC panel circuit breaker tripped, taking everything down in the middle of our Skywarn net. There are two receptacles near our equipment. One is normal power, the other is the red Critical Power receptacle. What problems would anyone see if we would feed everything from the normal power circuit, and if it would ever trip off, switch to the red receptacle. That way, if lightning trips the normal circuit, we would instantly feed our equipment from the red receptacle. This sounds so simple, and I'm inclined to build such a setup, but am I missing something obvious that could cause problems? Any better ideas? Laryn K8TVZ
