Kimmo, I thought you may be in Europe. I think you may be correct
about developing a dipole antenna. I've had an amateur radio license
for over 50 years, and have made several antennas over that time. The
dipole is a simple design and does not require a ground plane. Flarm
in the US uses a different frequency and the antenna would be to be
cut to a different length.
I have no arguement with Flarm in other areas of the world, were it
has been widely implemented. However, because of the late start for
Flarm in the US, I think it is doing a disservice to pilots here. The
range problem should be resolved in the future. Even if it had 10 km
range, it's the wrong product for US airspace.
Charlie
On Mar 24, 8:07*pm, Kimmo Hytoenen wrote:
Charlie,
I am located in Finland, Northern Europe.
Idea of FLARM is good, and when correctly installed (in both
planes approaching) it is a very good system. We have invested
a lot of money into these equipment, and trying to get best use
of those. It is not easy in all planes.
What I would like to see is a streamlined antenna housing, which
is installed into the nose of a glider plane, with build-in dipole
antenna, or half dipole.. Something looking likehttp://www.pharad.com/uhf-to-c-band-uav-antenna.html
It should not be to difficult to make those out of class-fiber, or
special plastic. Dipole antenna design is well known.
Possibly we should start another noncommercial project
developing those. Metal foil/PCB antenna in middle or some-kind
composite, streamlined plate. Mounting trough two 5 mm holes.
This should not be rocket-science, and cost should be less than
astronomical (I did ask prices from Pharad... 
-kimmo
At 23:58 23 March 2012, cfinn wrote:
Kimmo, you didn't say where you are located. However, I think
you are
outside the US. *The Power Flarm being pushed in the US is a
different
device then the Flarm units being used successfully in Europe
and
other areas.
Also, I think those that are pushing Power Flarm use in the US
are
doing a disservice to pilots. The US is mandated to use ADS-B
in most
aircraft by 2020. The UAT version of ADS-B was developed
specifically
as a lower cost system for general aviation. In addition to
traffic
alerts, it also provides ID to ATC, and other services such as
weather
and TFR's. It's true that ADS-B in it's raw form doesn't provide
the
same alert suppression that Flarm does for gliders. However, it
would
not be difficult to add those routines to soaring software in a
PDA,
etc. After all, the processor in the Flarm is fairly low power.
Think of what the Power Flarm is trying to do verses what the
standard
European Butterfly Flarm. In Europe, the only consideration is
Flarm
to Flarm information, including air to air and ground hazards.
PowerFlarm is trying to add transponder and ADS-B
information. Now we
require more receivers, more antennas and more processing
power. The
software becomes more complicated because of the need to
integrate
three entirely different systems. With ADS-B, you have one
receiver,
one antenna, etc., and only need to process the ADS-B
protocol. I did
neglect to say, both also have a GPS receiver.
I'm not about to become involved in a big discussion (read
bitch
session) about why ADS-B won't work for gliders. Some people
have
vested interests in pushing Flarm.
Charlie
On Mar 23, 6:57=A0pm, Kimmo Hytoenen *wrote:
I have installed several FLARM units. Most installations have
been
successful, i.e. the detection range is larger that the green
area
indicated in the FLARM range analysis. However in one LS-7
I have
not been able to locate antenna right yet. It looks like the
compass
of that plane, located on top of the instrument panel, is
blocking the
field into 11 clock direction.
My opinion is, that FLARM is a good tool when the antennas
are
correctly positioned. It might give you that critical 10
seconds time
to react. However. antenna positioning remains largely
unsolved
problem. I await with interest the development of two
antenna
systems for PowerFLARM.
We use LED based simple FLARM displays which show the
nearest
airplane, green when no danger, and red/alarm in danger.
Additionally we are building connections to devices like
Winpilot or
XCSoar to show all nearby traffic detected by FLARM. That is
also
great when you are flying with other people - you know
where they
are, and what they are doing. Each FLARM unit has it's own
code,
and you can nickname them. You might like to know if it's
the local
von Richthofen approaching from sun's direction, or
someone more
friendly.
At least I know couple pilots who - uh - need more
clearance, I
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