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.
Such use would be legal under FCC Part 15. Note:
Section 15.103 Exempted devices.
The following devices are subject only to the general conditions of
operation in Sections 15.5 and 15.29 and are exempt from the specific
technical standards and other requirements contained in this Part. The
operator of the exempted device shall be required to stop operating the
device upon a finding by the Commission or its representative that the
device is causing harmful interference. Operation shall not resume until
the condition causing the harmful interference has been corrected. Although
not mandatory, it is strongly recommended that the manufacturer of an
exempted device endeavor to have the device meet the specific technical
standards in this Part.
(a) A digital device utilized exclusively in any transportation
vehicle including motor vehicles and aircraft.
(b) A digital device used exclusively as an electronic control or
power system utilized by a public utility or in an industrial plant. The
term public utility includes equipment only to the extent that it is in a
dedicated building or large room owned or leased by the utility and does not
extend to equipment installed in a subscriber's facility.
(c) A digital device used exclusively as industrial, commercial, or
medical test equipment.
(d) A digital device utilized exclusively in an appliance, e.g.,
microwave oven, dishwasher, clothes dryer, air conditioner (central or
window), etc.
(e) Specialized medical digital devices (generally used at the
direction of or under the supervision of a licensed health care
practitioner) whether used in a patient's home or a health care facility.
Non?specialized medical devices, i.e., devices marketed through retail
channels for use by the general public, are not exempted. This exemption
also does not apply to digital devices used for record keeping or any
purpose not directly connected with medical treatment.
(f) Digital devices that have a power consumption not exceeding 6
nW.
(g) Joystick controllers or similar devices, such as a mouse, used
with digital devices but which contain only non?digital circuitry or a
simple circuit to convert the signal to the format required (e.g., an
integrated circuit for analog to digital conversion) are viewed as passive
add?on devices, not themselves directly subject to the technical standards
or the equipment authorization requirements.
(h) Digital devices in which both the highest frequency generated
and the highest frequency used are less than 1.705 MHz and which do not
operate from the AC power lines or contain provisions for operation while
connected to the AC power lines. Digital devices that include, or make
provision for the use of, battery eliminators, AC adaptors or battery
chargers which permit operation while charging or that connect to the AC
power lines indirectly, obtaining their power through another device which
is connected to the AC power lines, do not fall under this exemption.
(i) Responsible parties should note that equipment containing more
than one device is not exempt from the technical standards in this Part
unless all of the devices in the equipment meet the criteria for exemption.
If only one of the included devices qualifies for exemption, the remainder
of the equipment must comply with any applicable regulations. If a device
performs more than one function and all of those functions do not meet the
criteria for exemption, the device does not qualify for inclusion under the
exemptions.
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: Hare,Ed, W1RFI [mailto:w1rfi@arrl.org]
> Sent: Tuesday, December 18, 2001 10:58 AM
> To: rfi@contesting.com
> Subject: FW: [RFI] 433 Mhz Wireless Thermometer
>
>
>
> -----Original Message-----
> From: Ian White [mailto:G3SEK@ifwtech.com]
> Sent: Tuesday, December 18, 2001 2:59 AM
> To: w1rfi@arrl.org
> Subject: Re: [RFI] 433 Mhz Wireless Thermometer
>
>
> Hello Ed
>
> The RFI reflector blocked the following posting for some
> reason. Please
> could you forward it, before it loses all relevance.
>
>
> Hare,Ed, W1RFI wrote:
> >
> >Actually, these 433 MHz devices have been "mainstream" for
> quite some
> >time.
> >
> And in Europe for even longer. It all started with one
> country allowing
> 433.92MHz for car keys, and then the pressure was on, because
> no country
> can realistically stop people at its borders because their
> cars use the
> wrong frequency. Very soon, 433.92MHz was all over the European Union,
> and made into an official ISM band (see below). Next thing we
> know, it's
> world-wide. Welcome to the global economy.
>
> >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.
>
> You need to keep a strong watch on that, because
> transmissions in Europe
> have gradually crept up from the "one-shot" requirements of
> car keys to
> near-continuous broadcasts of traffic data (an acknowledged mistake in
> licensing, but still a precedent for other intensive uses).
>
> >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.
>
> Last Christmas I was horrified when the in-laws in the USA bought my
> wife an Oregon Scientific radio-linked thermometer for her outdoor
> greenhouse. Horrified, because I operate moonbounce on
> 432MHz, and this
> gadget operates on... you guessed it!
>
> Well, it has worked out fine. With about 50ft separation between the
> remote transmitter and my EME array, there is nothing to be heard.
> Neither does 1kW on 432.01 interfere with the data link on 433.92.
>
> This doesn't mean that all 433.92MHz modules would be equally good -
> there are some very cheap and nasty superregen designs out there - but
> it proves that coexistence can be possible.
>
> The real trouble is close to amateur digipeaters and packet
> nodes using
> that frequency intensively. Some car owners find themselves
> locked out,
> and it's a major problem for the breakdown services. Other frequencies
> outside the European ham band are also used (the band is narrower than
> in the USA) but that means that the interference to car
> locking systems
> comes from police and military services - who are much tougher to deal
> with than hams!
>
> --
> 73 from Ian G3SEK Editor, 'The VHF/UHF DX Book'
> 'In Practice' columnist for RadCom (RSGB)
> http://www.ifwtech.com/g3sek
>
> --
> 73 from Ian G3SEK
> _______________________________________________
> RFI mailing list
> RFI@contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
>
|