Hello, Dave,
Actually, these 433 MHz devices have been "mainstream" for quite some time.
These devices are FCC Certificated under Part 15 rules as "periodic
emitters." The ones I have look at transmit for about 50 milliseconds every
30 seconds or so. Most operate on 433.92 MHz, a European Industrial,
Scientific and Medical band. To date, I have no reports of harmful
interference to Amateur communications from legal devices. One fact that is
not well understood amongst amateurs is that all amateur spectrum is shared
with somebody. Part 15 devices can legally operate on any amateur
frequency (and most non-amateur frequencies, too) at the various levels
defined in the rules. They are unconditionally secondary to other radio
services.
The whole matter then becomes one of actual harmful interference. If there
is interference, the operator of the Part 15 device is required to correct
the interference. Merely hearing a Part 15 signal in "our" bands, though,
does not meet the standards of interference as defined in the rules. This
is not necessarily a bad thing. On 70 cm, we are secondary to the government
users; on 30 meters, we are secondary to commercial users. How would we feel
if they said, "We can hear the hams on 'our' bands, so they gotta' get out?"
The periodic emitters are not to be confused with some of the data
transmitters and video transmitters that also operate on 433 MHz. From what
I have seen, these are NOT Cerftificate, nor could they be at the ranges the
manufacturers claim.
For ARRL info on Part 15, see:
http://www.arrl.org/tis/info/part15.html
73,
Ed Hare, W1RFI
ARRL Lab
225 Main St
Newington, CT 06111
Tel: 860-594-0318
Internet: w1rfi@arrl.org
Web: http://www.arrl.org/tis
73,
Ed Hare, W1RFI
ARRL Lab
225 Main St
Newington, CT 06111
Tel: 860-594-0318
Internet: w1rfi@arrl.org
Web: http://www.arrl.org/tis
> -----Original Message-----
> From: David O Hachadorian [mailto:k6ll@juno.com]
> Sent: Monday, December 17, 2001 3:43 AM
> To: rfi@contesting.com
> Subject: [RFI] 433 Mhz Wireless Thermometer
>
>
> Sunday's Target ad has a Wireless Thermometer, whose
> "Transmitter has a 100' range." A picture of the unit
> clearly shows "433 Mhz wireless" on the face of the unit.
>
> It's only $18.88, so it looks like the 70 cm. intruders
> are going mainstream.
>
> Dave Hachadorian, K6LL
> Yuma, AZ
> K6LL@juno.com
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>
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