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Jeff Liebermann wrote: My guess(tm) is that the higher power 433MHz devices can only be sold in Europe. Yet, that's not apparent on any of the sites selling 433MHz data radios. "FCC Compliance testing Using the MICRF112" http://www.micrel.com/_PDF/App-Notes/an-55.pdf Page 9 has the calcs for a typical key fob transmitter. 36 microwatts. I've run into interference in a local shopping mall parking lot, which is sufficient to almost completely block 433 MHz car keyfobs from working. It comes from a local noodle restaurant, which uses a wireless order-taking system... from the sound of the transmissions over the air, I think the central node is polling the hand-held order entry units 3-4 times per second (well in excess of the Part 15 periodic radiator limit). It's quite audible for about a city block around the restaurant, in at least some directions. I got a look at one of the handheld terminals, and did not see any sort of FCC licensing or type-acceptance sticker. -- Dave Platt AE6EO Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
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