European manufacturers of collision avoidance hardware for sailplanes are
proposing to use 433 MHz for the signals from their aircraft mounted transmitters.

These would use a propriatary (secret) signal protocol to transmit position,
altitude, velocity, and other tracking information to other aircraft with their
equipment on board.

While it is a sense of "radiolocation", it is not radar in the sense of current
radiolocation activities on the band.

Note that the transmitters and receivers will be located in aircraft (not just
sailplanes), and will cover a wide area. As collision avoidance equipment they
would likely be considered safety of life, and not get along well with shared
frequencies.

I have not heard of this in the amateur community, and I doubt that the ARRL
knows about it, though they have been objecting to ground based robots operating
on those frequencies.

It sounds like a camel nose in the tent.

Alan
wa6azp



From: Westbender
Newsgroups: rec.aviation.soaring
Subject: Flarm in the US
Date: Thu, 12 Aug 2010 18:10:50 -0700 (PDT)

On Aug 12, 4:48=A0pm, Dave Hoppe wrote:
I'm waiting for one more response regarding flarm frequency and
approval status in the US.

And here it is:

Dave,

no problems, I'm very glad to help you!

It is a free frequency (SRD). In Europe we use 868Mhz, in the US it
will be 433Mhz. PowerFLARM automatically chooses the right frequency
for the place you are at - this means you can also use yours in europe
e.g. on competitions without having to change settings.

FCC approval is on its way and is going to be done before first units
start shipping.

Cheers
Marc