US Power FLARM Antennas

On Jun 20, 7:07*pm, John Cochrane
wrote:
On Jun 20, 2:27*pm, FLARM wrote:

Mounting the FLARM antenna in front of the compass is by far the best location unless you have metal or carbon vent outlets forward of it at the same height.

We will publish an 'Antenna Installation' application note this week.
Don't worry too much about the ADS-B antenna, the signals it receives are pretty strong.

FLARM

"FLARM" You're listening! *Please please please find a better antenna
than this ugly center-fed dipole with plastic attachment that goes
right in our field of vision. The RAS thread found lots of bottom-fed
and bottom-mounted dipoles. Please check that one of them works and
send an antenna that even plausibly is suited for a bottom-fed
installation on a glider glareshield!
John Cochrane

I agree with John. I would like a bottom-fed installation as well.

I'm wondering if an external solution would be the best way to go.

The Butterfly PF site has some interesting external antennas, but they look kinda hi-drag to my uneducated eye:

http://www.butterfly-store.de/en/Col...LARM/Antennas/

Seems to me that a streamlined bottom-fed dipole mounted on top of fuselage just behind the canopy would provide the best coverage (nothing in front or back of it) and minimal drag (less than the TE probe), without cluttering up the cockpit. For gliders with carbon fiber fuselages, might need to add a bottom antenna. What we need is an antenna that can be removed easily from it's socket, so it will not interfere with the top of the trailer when the glider is derigged.

Make the socket a pass-through, plug in the antenna (held in place with an O-ring?), connect the co-ax in the fuselage, done.

Nothing in the field of view in the cockpit (whiskey compasses on the glareshield? really? when was the last time you ACTUALLY used that relic), easier to clean the inside of the canopy, etc. After all the point is to make it EASIER to see traffic!

Anybody know someone who makes custom antennas? How about an SSA non-profit initiative? Or better yet, Bumper, you reading this?

Kirk
66

On 6/20/2012 5:29 PM, Andy wrote:

Hope the antenna installation guide considers that most pilots like
to clean the inside of the canopy before every flight. On many
modern gliders the glareshield is attached to the canopy leaving
little space for a hand and cloth even when no antenna is present.

"Most"? I'm really curious about what is making the inside of your
canopy so dirty it requires such frequent cleaning? Do you tow from a
dirt airstrip?

I clean mine once a year, and I usually can't tell the difference;
however, if I cleaned it before every flight, I'd worry the
inside would be covered with fine scratches after 17 years and 100's of
flights.

Just to be clear, I'd like the antennas to be smaller or placed
somewhere else, so I'm not looking or taking pictures through them. But,
I'm getting use to them.

It's a bit surprising that people think the PCAS antenna
positioning is not important. I understand that the signal is
stronger that the FLARM signal, but ZAON is quite emphatic about the
need for proper positioning of the MRX PCAS antenna.

The signal is about 150watts/0.020watts = 7500 times stronger -
transponder signals are a lot stronger! My MRX manual isn't as emphatic
as yours, apparently, saying only:

"The preferred placement for MRX is on the glare shield of your aircraft
with the antenna angled vertically. This configuration affords MRX the
best possible sensitivity and accuracy. Position MRX at least 2” away
from any magnetic compass to avoid potential magnetic interference."

It also has a shorter antenna, and perhaps that makes it's positioning
more important than the PowerFlarm PCAS antenna.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

I spent the day installing my FLARM brick today. The antennas were added to the side of the glare shield (Discus 2b) VIA a $1 door stop and Velcro to give it a reasonable vertical orientation without banging on my canopy. I was leaning to balsa wood, but in my small town I couldn't find any. I will spruce up the installation a bit by painting the door stops with textured black paint. Since independent analysis shows the antenna orientation only marginally affects reception and rotating the antenna in the same location does more damage than moving it off of vertical, this should be good enough. It isn't blocking my forward view like some of the "recommended" installations have shown. Of course, it is a work in progress like all other folks out there. If things go to pot, I'll make changes and let you know the results.

Craig