revisiting the 434 MHz band

Wolfgang Spraul wolfgang at
Wed Jul 21 07:08:23 EDT 2010


> This leaves two choices: 1) either live with a design that operates
> in different bands, depending on location, or go to what appears to
> be the only globally safe place, the 2.4 GHz band.

If you read long and contradictory regulating paperwork long enough,
you will always find a reason not to do something.
Am I reading the Wikipedia article correctly in saying that "ISM rules
prohibit using ISM for communications"?
What is 'communications'? Is a Skype call over Wi-Fi actually illegal?
Or are there other regulatory documents that override this?

For the German articles you are pointing to, the distinction between
'voice application', 'data application' and 'technical application'
indeed does sound very German to me :-) Glad I don't have to enforce this,
and glad I'm in China where we are just making millions of stuff that works,
and others can find the regulatory paragraph this falls under :-)

What are our priorities:

1) Build hardware that is globally unique.
2) Move logic to comply with local regulations into software.

Why have we started to look at the 433 MHz band in the first place? Because
we find readily available and cheap RF ICs working in that band. Your
suggestion of building hardware that can operate in both 868 and 915 is
interesting, although I would feel better, technically and legally, if we
wouldn't be the first ones doing such a design. Do you know RF ICs or
modules that can do this?
For now the 433 MHz band is a very established, high-volume band with many
of applications, in the whole world. I will mail you a few HopeRF modules...

In parallel, nothing against 2.4 GHz, let's see whether we can find an RF IC
that meets our needs in that band. Any leads?


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