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Wireless

Wireless Fire Station

The ISP-Wireless list discusses hooking up a fixed wireless antenna using the power line connected to a fire station's siren, right there on the roof.

[July 31, 2000]

On the ISP-Wireless list in July, PF asked about tapping off rooftop power for wireless:

"Since rooftop electrical (for lighting, sirens, etc.) is usually 220VAC or higher, has anyone come across an outdoor step down transformer for using the in-place power for wireless?"

A number of respondents had concerns about this:

[RS warned] "I wouldn't expect anyone to let you tap off their rooftop cooling units; the extra load probably wouldn't be welcome."

[MS added] "Use a very good UPS unit, as you'll likely see some big spikes."

[RK worried] "After a power failure, that UPS will pull quite a load while recharging. I've seen some poorly-designed 'data centers' blow all kinds of breakers after a fifteen-minute power failure because a couple dozen UPS's are overtaxing the circuits they're on. You're better off being on your own circuit."

So PF clarified his original question:

"It's a siren on a fire company, tested and installed, so it's a reliable source of A/C. It's three floors up in the middle of a roof. They have to use the hook-and-ladder to get us up there, so I really don't want to run my own conduit/cable. I was hoping there would be an easy way to tap into the 220 and use that for power."

[But SV noted] "I would worry about the noise created on the circuit when the rooftop unit kicks on."

[BM warned] "The fact that it's only accessible by aerial equipment makes it seem to me that there would only be power at the siren location when it's activated. Internet access would not be marketable for thirty-second durations at random times during the day! :-)"

[PF answered] "No, this one has a line coming right off the utility box, goes straight up to the siren."

Finally, JR offered a basic solution, with a link to a site selling a step down transformer weighing fifteen pounds:

"Kind of heavy, but for $49 who's complaining: http://www.220giftcenter.com/750a.htm. It would be a matter of cutting the plug off the end and tapping into their 220. Being on a separate breaker would be great, but I don't think with this device it would be necessary."

 —End