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Old July 24th 12, 07:16 PM posted to rec.radio.amateur.antenna
Dave Platt Dave Platt is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 464
Default 315mhz/433mhz transmitter

In article ,
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
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