Actually 18.301 says the following:
"ISM equipment may be operated on any frequency above 9 kHz except as
indicated in Sec. 18.303."
and...
Sec. 18.303 Prohibited frequency bands.
Operation of ISM equipment within the following safety, search and
rescue frequency bands is prohibited: 490-510 kHz, 2170-2194 kHz, 8354-
8374 kHz, 121.4-121.6 MHz, 156.7-156.9 MHz, and 242.8-243.2 MHz.
It is also interesting to read 18.305 relating to Field Strength Limits,
especially the following (in part):
(a) ISM equipment operating on a frequency specified in Sec. 18.301
is permitted unlimited radiated energy in the band specified for that
frequency.
(b) The field strength levels of emissions which lie outside the
bands specified in Sec. 18.301, unless otherwise indicated, shall not
exceed the following:<snip>
Industrial heaters and <5,725 MHz Any Power 10 uv/m at 1,600 meters
RF stabilized arc welders. >5,725 MHz Any Power (\2\)
<snip>
\2\ Reduced to the greatest extent possible.
They're all available here:
<http://www.access.gpo.gov/nara/cfr/waisidx_03/47cfr18_03.html>
27.1 MHz +/- 163 KHz covers CB channels 1 through 27 almost perfectly.
Just call it a welder! ;-)
73, Tony W4ZT
Dave Haupt wrote:
>27.12 MHz is one popular ISM frequency.
>
>13.56 MHz is probably the most popular. Tune any
>receiver to 13.56 MHz and you'll always hear a
>carrier, usually a bit wobbly and often with AC hum.
>Gigawatts of power are used at 13.56MHz as
>lumber-drying kilns in the Pacific Northwest, and it
>is the most-used frequency for plasma etch processing
>in semiconductor fabrication. There are thousands of
>50kW 13.56 MHz generators sold every year into the
>semiconductor industry.
>
>The ISM frequencies, per FCC rule 18.301 are:
>
>ISM Frequency Tolerance
>6.78 MHz +/- 15.0 kHz
>13.56 MHz +/- 7.0 kHz
>27.12 MHz +/-163.0 kHz
>40.68 MHz +/- 20.0 kHz
>915 MHz +/- 13.0 MHz
>2,450 MHZ +/-50 MHz
>5,800 MHz +/-75.0 MHz
>24,125 MHz +/- 125.0 MHz
>61.25 GHz +/- 250.0 MHz
>122.50 GHZ +/- 250.0 MHz
>245.00 GHz +/-1.0 GHz
>
>Generally, on an ISM frequency, you can generate as
>much power as you want, and even radiate it, as long
>as you are NOT using the energy for communicating.
>So, you could be doing radar, or you could be drying
>lumber, searching for cancerous tumors, or other such
>things, but you can not be sending information (voice,
>data, CW, RTTY, etc). No license required.
>
>Note that 6.78, 13.56, 27.12, and 40.68 are all
>harmonically related - this is intentional. A "cheap
>dirty" power generator on 13.56 is likely to generate
>harmonics, therefore the harmonic frequencies are as
>legally uncontrolled as the fundamental.
>
>Perform a Google search on any of those frequencies
>(e.g. "27.12 MHz") and you'll come up with lots of
>links to experiments about using RF energy to weld
>plastic, seal bags, cure cancer, and so on.
>
>73,
>
>Dave W8NF
>Not at Dayton this year....
>
>
>
>Yahoo! Mail
>Stay connected, organized, and protected. Take the tour:
>http://tour.mail.yahoo.com/mailtour.html
>
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>
>
>
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