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[RFI] 433 Mhz Wireless Thermometer

To: <rfi@contesting.com>
Subject: [RFI] 433 Mhz Wireless Thermometer
From: w1rfi@arrl.org (Hare,Ed, W1RFI)
Date: Tue, 18 Dec 2001 17:55:58 -0500
The biggest hope I can see is that if they cannot use  433.92 MHz worldwide,
we may be able to talk them into using a different frequency in the US. The
hams in the auto industry can just imagine the outcry of "questions" they
will get from hams if they use a ham frequency.  I have done what I can to
reinforce that understanding. :-)

Under US rules, they can really use any frequency they want. If they decide
to follow the regs for periodic emitters, they can use any frequency above
70 MHz, except for the restricted bands.

BTW, the wireless thermometers are "periodic emitters." See
http://www.arrl.org/tis/info/part15.html. As noted here, hams have not
experienced harmful interference from the legal devices, although an ATV
receiver on 70 cm might have a brief burst every 30 seconds or so. I DON'T
want to ask the FCC if this crosses the threshold to being deemed "harmful
interference" in the regulatory sense. :-)

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: Ian White, G3SEK [mailto:G3SEK@ifwtech.com]
> Sent: Tuesday, December 18, 2001 12:21 PM
> To: rfi@contesting.com
> Subject: Re: [RFI] 433 Mhz Wireless Thermometer
> 
> 
> Hare,Ed, W1RFI wrote:
> >As a follow-up, a ham I know who works in the auto industry 
> had to do a 
> >bit of research on 433.92 Mhz. The auto industry is 
> considering using 
> >that frequency (among others) with their tire-pressure 
> sensors (a few 
> >milliseconds of transmission every several minutes).  He 
> reported to me:
> >
> >> 433.92 appears not to be permitted in Australia, Chuna, Hong Kong,
> >> Indonesia, Malaysia, New Zealand, Singapore, South Korea.  Probably
> >> most of Asia/Pacific included.
> >
> >I have not verified this info.
> 
> Thanks for forwarding my earlier message, Ed.
> 
> That's  an interesting list of countries, and I hope they can 
> "hold the 
> line" to keep 433.92MHz a ham frequency. However, since Japan 
> is not on 
> the list, and that frequency is liable to be used in imports 
> from Europe 
> and the USA, I don't hold out much hope for the long term...
> 
> 
> -- 
> 73 from Ian G3SEK          Editor, 'The VHF/UHF DX Book'
>                            'In Practice' columnist for RadCom (RSGB)
>                             http://www.ifwtech.com/g3sek
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