I'm familiar with the purpose of the ISM band. My question is why is it
important that the ISM band be the same around the world? I've looked
at the FCC site and the ITU and I didn't find an answer.

Kensei

wrote in message
ups.com...
I'm familiar with the purpose of the ISM band. My question is why is it
important that the ISM band be the same around the world? I've looked
at the FCC site and the ITU and I didn't find an answer.

Kensei


Because the ISM equipment is shipped around the world and the interference
from such equipment can cause interference which can also propagate around
the world.

Consider 27MHz, this is an ISM band and diathermy machines make a hell of a
racket. When propagation is good, only a few watts is required for
international communications. These machines leak RF and it can cause RF
interference around the world, that is, unless the rest of the world is also
using the same frequency.

It reduces the cost of manufacture if all the medical machines use the same
frequency bands instead of having to redesign them to suit each country.
Same applies to industrial and scientific applications. It's called band
planning.

Brad.

Thanks. That's basically what I thought. Also, some very mobile
equipment which are not ISM equipment but use this band (e.g., laptops
running some version of 802.11) could also interfere with critical
communications in another country if ISM were not standardized. But, as
you have pointed out, the ISM band was originally developed for the use
of ISM equipment so they could be shipped and moved around the world.
It seems to me the later use of this band by other equipment (e.g.,
mobile laptops) was done to capitalize on the fact that no license is
needed to broadcast in this band and broadcasts will not interfere with
other critical communications when moving from country to country.

Thanks,

Jeff

In article . com,
wrote:
I'm familiar with the purpose of the ISM band. My question is why is it
important that the ISM band be the same around the world? I've looked
at the FCC site and the ITU and I didn't find an answer.

I suppose you could see if you could find some sort of report or
proceedings from the treaty meeting that set up the bands as they
are. Probably in the 1950s, but it could have been earlier.

I'd go with "just because". Or the common sense reason: if you can
radiate unlimited power...

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)