Transponder Antenna

[Rick Fuller]

I'm seriously considering installing a transponder
in our Discus CS. Does anyone have any experience
with the dipole antenna model L2 made by Advanced Aircraft
Electronics (AAE) and sold on the Wings & Wheels web
site? It seems like a good solution for an internal
antenna in a fiberglass fuselage. Mounting location?
Orientation? Test results?

Thanks in advance.

Rick 'CL'

[[email protected]]

I installed an L2 antenna in the forward side wall of my cockpit
(LS-8) with my Becker transponder. I attached it to the side of the
cockpit with velcro. It has worked perfectly. The Reno tower reads
my transponder in all orientations to the tower and has no problems
when I am circling. The antenna will work with any placement as long
as there is no carbon in the panel the antenna is mounted on.

Guy Acheson "DDS"

[Darryl Ramm]

On Jan 29, 6:30 pm, wrote:
> I installed an L2 antenna in the forward side wall of my cockpit
> (LS-8) with my Becker transponder. I attached it to the side of the
> cockpit with velcro. It has worked perfectly. The Reno tower reads
> my transponder in all orientations to the tower and has no problems
> when I am circling. The antenna will work with any placement as long
> as there is no carbon in the panel the antenna is mounted on.
>
> Guy Acheson "DDS"

The main thing is peopel are using transponders, fantastic (esp.
around places like Reno).

But as for "any placement" SSR radar transponder signals are
vertically polarized. So for best performance you should have the
antenna aligned roughly vertically, as opposed to say lying along the
longitudinal axis of the glider. Even though average power levels are
low I personally would not position a transponder antenna close to my
body.

My advice, as mentioned before, is to look up and try to follow the
glider manufactured recommended installation procedure. Schempp-Hirth
publishes transponder antenna information for their aircraft including
the Discus CS. In this case they recommend an external stub antenna.

The key issue raised in the original post was "test results" - lots of
do it yourself transponder installs all report "it works fine". The
problem is without really complex (=impractical) measurements it is
really difficult to determine how well an antenna install is really
working.

Once concern with dipole antennas is interference from metallic
objects like landing gear structures close to the antenna.
Conventional quarter wave antennas have a benefit of being relatively
easy to shield from these by their ground plane. But as long as the
dipole antenna is a few antenna lengths away from metallic objects you
should be fine.

Darryl

[[email protected]]

On Jan 29, 8:27 pm, Rick Fuller >
wrote:
> I'm seriously considering installing a transponder
> in our Discus CS. Does anyone have any experience
> with the dipole antenna model L2 made by Advanced Aircraft
> Electronics (AAE) and sold on the Wings & Wheels web
> site? It seems like a good solution for an internal
> antenna in a fiberglass fuselage. Mounting location?
> Orientation? Test results?
>
> Thanks in advance.
>
> Rick 'CL'

Please guys, contact the manufacturer (or rep) and get a
properly designed and approved installation. Antennas
transmitting near the panel will yield unhappy results
with your other avionics and PDAs and gadgets.
Really.

Hope this helps,
Best Regards, Dave

PS: Here's an example of a proper installation,
though you cannot see the internal reinforcements
etc:
http://www.nadler.com/antares/DaveLandingAntares.jpg

[JJ Sinclair]

On Jan 30, 4:26*am, wrote:
> On Jan 29, 8:27 pm, Rick Fuller >
> wrote:
>
> > I'm seriously considering installing a transponder
> > in our Discus CS. *Does anyone have any experience
> > with the dipole antenna model L2 made by Advanced Aircraft
> > Electronics (AAE) and sold on the Wings & Wheels web
> > site? *It seems like a good solution for an internal
> > antenna in a fiberglass fuselage. *Mounting location?
> > *Orientation? *Test results?
>
> > Thanks in advance.
>
> > Rick 'CL'
>
> Please guys, contact the manufacturer (or rep) and get a
> properly designed and approved installation. Antennas
> transmitting near the panel will yield unhappy results
> with your other avionics and PDAs and gadgets.
> Really.
>
> Hope this helps,
> Best Regards, Dave
>
> PS: Here's an example of a proper installation,
> though you cannot see the internal reinforcements
> etc:
> * *http://www.nadler.com/antares/DaveLandingAntares.jpg

Good point, Dave.......................I know of one case where the
L-2 antenna interfered with the GPS antenna because they were too
close to each other (both under the hood). The L-2 manufacturer tells
us to keep it 5 feet away from pilot or passengers. I'd make a curved
plate from the provided balsawood (they don't want it glued directly
to fiberglass) and locate it as far back in the tail boom as I could
reach with a 5' stick. It should be vertical and this can be
accomplished by curving the balsa plate to match your fuselage side.
Put it on the side away from the elevator push-rod. Easiest done with
fuselage on its side.Epoxy the antenna to your balsa plate first and
have the lead all hooked up, then goop up the plate with epoxy and
place it in the desired location and let gravity keep it there until
the epoxy dries. One wrap of masking tape will keep the antenna on
your stick and can be removed after epoxy cures. Remember to support
the lead (RGU-58) about every 3', so it can't flop around. Could slide
a plastic tie down your pneumatic tubes and secure the lead to them.
Best to have the output checked...................which I haven't got
around to, yet, but Reno,Sacramento and Oakland are reading my squawk
and with my PCAS telling me who's close and I feel quite safe these
days. It even lets me know when someone (7V) leaves the
thermal........................Leaching aid!
JJ

[Brian Bange]

I put mine down in the tail boom. I mounted a paint
stick sized piece of wood in the vertical position
and tie wrapped the antenna to it. It passed inspection
and seems to work fine. I wanted it as far away from
my body as possible. The Microair manual gives very
clear instructions as to cable length, mounting and
material. It is a nice antenna, and does not require
you to drill holes in your ship.

Brian
>> > I'm seriously considering installing a transponder
>> > in our Discus CS. =A0Does anyone have any experience
>> > with the dipole antenna model L2 made by Advanced
>>>Aircraft
>> > Electronics (AAE) and sold on the Wings & Wheels
>>>web
>> > site? =A0It seems like a good solution for an internal
>> > antenna in a fiberglass fuselage. =A0Mounting location?
>> > =A0Orientation? =A0Test results?
>>
>> > Thanks in advance.
>>
>>

[[email protected]]

On 30 jan, 03:30, wrote:
> I installed an L2 antenna in the forward side wall of my cockpit
> (LS-8) with my Becker transponder. *I attached it to the side of the
> cockpit with velcro. *It has worked perfectly. *The Reno tower reads
> my transponder in all orientations to the tower and has no problems
> when I am circling. *The antenna will work with any placement as long
> as there is no carbon in the panel the antenna is mounted on.
>
> Guy Acheson *"DDS"

Hi,

Pls be very very very carefull if you place a transponder antenna
inside your cockpit.

The radiation of such antenna is really strong, if you do not want to
have an extreme increased chance on cancer you really need to place
the antenna away from your body.

It's hundreds time more strong than the radioation of a mobile phone,
and if no scientific persons wants to say mobile phones are safe, then
transponder antenna's aren't definately not safe.
a 5 hour flight with the antenna next to your body is the same than 5
hours calling with 100 mobile phones at the same time

I have installed it after the bay doors of my engine, there is 2m and
a engine, fuel tank and 2 carbon wings between me and my
transonderantenna