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[OT] ISM Band

Technical Forum: PicBasic List 07/2001 to 12/2001: [OT] ISM Band

By Anonymous on Sunday, August 26, 2001 - 11:09 am:

Hi All

Do we have any radio hams on the list? Where can I get information about
the 433 MHz band (433.92 MHZ to be exact) licensing requirements? I've tried
the FCC page, part 15 etc, but ended up more confused than when I started.
I'd like to find out:
1. Is this a licensed band in the US?
2. Is it classified as usable for ISM applications?
3. What are the requirements for licensing at this frequency in the US, if

If someone could point me in the right direction to get the info I'm looking
for, I'd appreciate it.

Thanks in advance

By Anonymous on Sunday, August 26, 2001 - 05:04 pm:

I'm a radio man. I get all my info from the FCC. Don't
get the info anywhere else. 433.92 MHZ is not used
for ISM as far as I know. This is a license free band if
used according to part 15. If you exceed the power that
is allowed under part 15 or exceed any other spec. you
have just entered the 420-450 MHZ amatuer radio band
and licensing is required along with meeting the other long
list of requirements such as bandwidth, harmonics, type of
modulation, etc, etc.
What are you doing ? The only other qualified
source of info for this is the ARRL in Newington, Ct.
go to www.remote.arrl.org

By Anonymous on Sunday, August 26, 2001 - 05:11 pm:

Hello Fritz:

The short answer to your question is:
YES, the ISM bands are regulated even though "unlicensed" for certain specific
applications. It depends of the frequency and the transmitting power you intend
to use. The use of rf sub-assemblies manufactured by reputable OEM and intended
for unlicensed wireless applications are usually exempted from any
certification, provided you don't go commercial with your final device. Your
question is not of the realm of Radio Hams but of communication engineers... and
lawyers :-p. It is part 18 (not 15) of the FCC that covers your intended
use. And yes, even after 20 years in the trade, I still find the regulations

Read on for the longer answer, if necessary.

The allotment of radio bands and their usage is administered by an international
organization - the International Telecommunications Union (ITU). The planet is
divided into Radio Zones, which further define the allotment of radio bands and
their usage. It is up then to the national governments, through agencies and
departments, to specify, regulate, and adminsiter the use of the allocated bands
of the radio spectrum in the zone where the country is located. One of the most
important aspect of the regulation of the radio spectrum is to protect the bands
intended for applications such as radionavigation, radiolocation, distress
calling, and satellite links. Regulations are also in place for the protection
of licensed users, such as broadcasters.

In Canada, the radio spectrum is administered by the Canadian Government through
a department called Industry Canada. The regulated radio spectrum range from 9
kHz to 400 GHz. The unlicensed wireless low power devices regulations are
edicted under the Regulation RSS-210. More information and document download is
available directly from their Web sites at http://strategis.gc.ca/spectrum and
www.ic.gc.ca BTW, these regulations are a bit clearer than their FCC
counterpart ;-)

In the US, the radio spectrum is administered by the American Government through
an agency called the Federal Communications Commission (FCC). The regulated
radio spectrum range from 9 kHz to 3 THz. The unlicensed wireless low power
devices regulations are edicted under the Part 18 (A-C) of 47 CFR Ch. 1, pages
712-720. More information and document download is available directly from their
Web site at www.fcc.gov.

The manufacture and use of radio transmitters is strictly regulated. It does not
matter if the manufacturer of the transmitting sub-assembly claim that its use
is licence-exempt or not: it is your final responsibility as the ultimate
designer to insure compliance with the regulations. To determine if you need a
licence, you must consider the following criteria:
- Is the frequency you intend to use is restricted or for licensed users only
- If the frequency you intend to use is allowed without licensing, do you plan
to use an acceptable transmitting power (unlicensed wireless devices MUST be LOW
POWER - regulations specifies what power is permitted at which frequency)
- Is your mode of signalling and modulation acceptable for that specific band
(if you intend to transmit continuously, the permitted power level and frequency
choice is quite different than if you intend to signal by short bursts almost
- Finally, how many units do you plan to put "on the market" (onesies and
twosies are of much less concern than if you plan to innundate the planet with
your gizmo).

Wireless Low power Devices ARE regulated even though they are unlicensed. You
must check the applicable regulations to your intended apparatus as the
penalties are often quite steep, especially if you radio-jam a licensed user
because of a faulty or unauthorized design. Also, remember that unlicensed
really means that Low Power Devices are required to operate on a
“no-interference no-protection” basis, i.e. they may not cause radio
interference and cannot claim protection from interference.

The Radio Control and ISM bands most commonly used in North America are located
at 27, 40, 72 (model aircraft only), 75, 303-315, 418, 433, 902-928 (if using
spread spectrum), 916.5 MHz, and, for spread spectrum mode only, 2.4, and 5.1
GHz. In North America, it is a good idea to stay away from 418-433 MHz as you
are very close to bands allocated for powerful radiobeacons. In the US and
Canada, the 916.5 MHz band is usually the best choice for digital designs.
433.92 MHz ISM is more commonly used in the UK and Europe.

For 418, 433 and 916 MHz sub-assemblies, rule of thumb for unlicensed
trouble-free designs are:
1. you use a radio sub-assembly from a reputable manufacturer, and the specs
indicate an unlicensed final use;
2. your implementation of the sub-assembly is strictly in accordance with the
OEM specs
2. your antenna design is conform to the specs of the sub-assembly manufacturer
3. you do not use any kind of signal booster or weird radiator
4. you do not radiate at more than a few hundred feet (at the exception of
spread spectrum devices).
5. and finally, you do not commercialize your devices.

It is always a good idea to avoid continuous transmission - try to keep your
signalling momentarily, in bursts, even random if possible.

If you do build your device for commercial applications (as defined in Canada as
more than 5 units built - check for US requirements), then join the club of
frustrated rf designers: you will have to submit your gizmo and technical specs
to an accredited testing laboratory for the obtention of an FCC certification
and label, even though your device will not require any form of licensing from
your potential end-users. Beware, it is an expensive (and often painful)

I can't give you much more guidance unless you tell me exactly what you intend
to do.

Hope this help a bit.

(s) Normand Delisle

By Anonymous on Sunday, August 26, 2001 - 06:15 pm:

Thank you all for very thorough answers


By Anonymous on Monday, August 27, 2001 - 01:26 am:

Hi Fritz,

I have been developing a product for export to US and UK. Using a 433.92 RF
transceiver, my understanding is that this is an unlicensed ISM frequency,
however you must obtain certification within your country. The same applies
in the UK. In Australia, you only need to obtain C-tick compliance for the
regulations. This costs nothing. In your country, I have been told that it
will cost around $900 US for production devices. However, if you produce
and use a very small number of units, then you are exempt from
certification. The FCC specifies this in their regulations. Of course when
you fit an antenna to any OEM radio module, testing is required to ensure
that the device complies with the unlicensed regulations. This applies in
ALL countries. This gets complicated, however unless I obtain testing and
certification from an authorized testing centre in Australia, I am not
allowed to export to the US or the UK. I guess that means that if you use
an unlicensed frequency, then you have to obtain certification. HOW IS THAT
for simplicity!!!


By Anonymous on Monday, August 27, 2001 - 12:18 pm:

Someone else may know more, but I believe that range is amateur primary allocation
in the U.S.
So you'd need to have a control operator with at least a technician class
amateur ticket for each transmitter.
Sorry not familiar with "ISN"
Check the ARRL web site, digging around may find more help
Not sure of the exact bnad plans for satelite and/or weak signal usage but
I think 433MHz is in the weak signal range so remote control applications
could create a real conflict.
Hope you get better help

By Anonymous on Tuesday, August 28, 2001 - 01:39 am:

Hi Fritz,

It looks like it's ok...


Being ISM it means you don't have to licence the equipment - the
manufacturer does, so if you use a commercial module it should be fine.


By Anonymous on Tuesday, August 28, 2001 - 02:45 am:

CORRECTION! You may only use an RF module as is provided you use the
original antenna as supplied by the manufacturer and certified by a
governing body. If you purchase a Radiometrix module, RFM or anything else
and attach your own antenna, you MUST have it certified by your local
authority. This is YOUR responsibility!. This is because the antenna
design determines the effective radiated power out, and it is this that
determines whether you are within regulations. A power reading of +10dBm
out of a module means nothing without knowing the antenna specifications and
radiation patterns that is being used with such modules.


By Anonymous on Tuesday, August 28, 2001 - 06:03 am:

There are also limitations on unintentional radiation, which may be at other
frequencies than those intended-0-spurious emissions. there are many fine
labs around the USA and Europe that do this kind of testing for a fee. TUV
comes to mind--an international company with many offices. there are big
fines along with possible injunctions if you ignore this process. There are
also restrictions and labeling requirements.


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