PowerFlarm at Uvalde?

[snip]

Who said anyone was "highly disturbed"? I didn't.

OK you said "very disturbing". I am highly disturbed at all the
melodrama.

Can you cite any other GPS based gliding equipment that requires the
GPS
antenna to be installed more than 30cm from any other GPS antenna?

Classic FLARM product documentation for years has talked about 25cm
separation. So hopefully this type of spec is not a surprise to many
folks who have been interested in FLARM for a while. And there are
thousands and thousands of classic FLARM systems flying and those pilots
have managed to live with 25cm separation specs and the very occasional
need to jigger things around to reduce any interference issues.

The Flarm transmitter is ~1Ghz (~915 MHz in the USA). GPS receivers are
very sensitive and operate on 1.2/1.5 GHz and when you mix these things
together in a close environment there is just always going to be some
chance of interference. And I am not as worried about the engineering of
FLARM products as much as I am that of other systems that might suffer
interference. There are many shoddy/badly designed and installed devices
out there in the wild wild west of glider cockpit avionics.

The need in the USA for a permanently attached FLARM antenna was the
FCC's requirement not something FLARM wanted to do.

give a rat's arse about the compass but I do care that my other GPS
receivers (currently 3 of them behind or on the panel) continue to
work and
there are reports from Uvalde of interference to other GPS based
equipment.

Sure FLARM is covering their arse. If there are problems of
interference
with other equipment the first question will be "Did you meet the
antenna
separation requirements?"

Just install the unit, in the unlikely event you do have interference
issues move the GPS antennas and fix it. FLARM just cannot engineer a
transmitter that is guaranteed not to interfere with any random GPS or
other electronic product out there. And the first response from any
vendor in that type environment (where they have no control over the
engineering and installation of the other boxes) had to be to tell users
to first try separating the antennas.

I expect many pilots may well replace one existing GPS receiver as they
want the FLARM enhanced NMEA data. That obviously does not remove need
for other receivers or backup receivers but if you do happen to end up a
having problems and have three existing GPSAnyhow just install the unit,
in the unlikely chance you do have interference issues move the GPSs
antennas and fix it. FLARM just cannot engineer a transmitter that is
guaranteed not to interfere with any random GPS or other electronic
product out there. And the first response from any vendor in that type
environment (where they have no control over the engineering of the
other boxes) had to be to tell users to first try separating the
antennas.

if you do happen to end up with problems and really have three existing
receivers and a fourth in the FLARM it may be time to clean up/simplify
your avionics!

Why would anyone buy a piece of equipment knowing that they could not
meet
the installation requirements? Why would anyone build equipment with
strict antenna separation requirements and then make the radiating
antenna
non removable thus preventing it's relocation?

PowerFLARM has to work with closer antenna separation that 30cm. If
it
cannot, it needs a design change. If it can, the user manual needs to
be
revised.

The user manual could better explain the reasons these limits are there.


Darryl