John S wrote:
On 7/24/2012 12:12 PM, Jeff Liebermann wrote:

Microwatts doesn't seem to make sense as there are products being sold
that advertise 10mw and 100mw output power levels. Obviously they are
not being certified under Part 15. However, I can't find another US
service on 433MHz that qualifies (except ham radio). FCC frequency
allocations table is of no use:
http://ecfr.gpoaccess.gov/graphics/pdfs/er27ja12.018.pdf
433MHz is an ISM band, but only in region 1 (Europe) and not in region
2 (US).
http://en.wikipedia.org/wiki/ISM_band
My guess(tm) is that the higher power 433MHz devices can only be sold
in Europe. Yet, that's not apparent on any of the sites selling
433MHz data radios.

It appears that we have both looked very hard and have come to the same
conclusion. I now wonder if the US suppliers are unaware of the region
1/region 2 thing.

Here in Europe, 10mW ERP is allowed on 433 MHz. This of course does
not mean that all devices have that much power. I can understand that
a 13dBm transmitter device is allowed with an inefficient antenna and
still result in 10mW ERP or less. 100mW seems to be a bit off the
scale, who would want to waste that much power.

Unfortunately, "allowed" and "in use" are different things. It is
allowed to used 10mW handy talkies on 433 for unlicensed use, but in
reality those users have the wellknown Chinese devices (Wouxun etc)
that output 4 watts. Or they use a 50W standard HAM mobile transceiver.
Without license. On the amateur bands.