glider transponder

[Chris Marren]

Can anyone (maybe a Dutch gliderpilot) offer advice
to fitting a 175watt Becker transponder to a Ventus?
This is new to us in the UK. Type of aerial and the
best location for it? Does a carbon fibre fuselage
give problems? I'm thinking of putting the aerial in
the wheel bay.

[Dale and Rosemary Thompson]

We've got our transponder antenna mounted in the ventilation air duct
in the nose. Works just fine. Plane is a Russia, with no carbon
fiber.
On 3 Dec 2003 14:26:39 GMT, wrote:

>Can anyone (maybe a Dutch gliderpilot) offer advice
>to fitting a 175watt Becker transponder to a Ventus?
>This is new to us in the UK. Type of aerial and the
>best location for it? Does a carbon fibre fuselage
>give problems? I'm thinking of putting the aerial in
>the wheel bay.
>
>

Rosemary

To reply by e-mail, remove the "Nospam" from my address

[Rod]

My antenna is mounted outside - just off the center of the fuselage, near
the main wheel door

Regards,
Rod

[Eric Greenwell]

Chris Marren wrote:
> Can anyone (maybe a Dutch gliderpilot) offer advice
> to fitting a 175watt Becker transponder to a Ventus?
> This is new to us in the UK. Type of aerial and the
> best location for it? Does a carbon fibre fuselage
> give problems? I'm thinking of putting the aerial in
> the wheel bay.

The wheel bay is a bad location if it's a carbon fiber fuselage, and
even in a fiberglass fuselage, all the metal bits could easily interfere
with the signal in many directions.

On my ASH 26, the factory mounts it a couple of inches behind the wheel
well a few inches off center. No ground plane, as they say the carbon
fiber fuselage is adequate. Seems to work. The antenna is the common ~3"
wire rod with a little ball on top. Cheap, and it bends easily if it
hits anything. The airfoil shaped units won't bend, and might damage the
fiberglass, so I decided not to use that style. Swoopy looking, though.

The Feb and March 2002 issues of Soaring Magazine had a complete article
on transponders, antennas, and installation.

--
-----
Replace "SPAM" with "charter" to email me directly

Eric Greenwell
Washington State
USA

[bumper]

The transponder antenna should be mounted vertically as the signal is
vertically polarized, and preferably on the underside of the aircraft so the
aircraft structure doesn't interfere with the radiation pattern. Many pilots
prefer the antenna be located as far a practicable, within reason, away from
passengers to minimize any potential adverse effect from exposure to the
radiated energy - - may not be a factor, but why take chances. It's
important to use low-loss coax cable, follow manufacture's recommendations,
when remotely locating antenna..

Like Eric's, my transponder antenna is located on the belly just aft of the
gear doors, and the 175 watt Becker works well.

bumper

"Dale and Rosemary Thompson" > wrote in
message ...
>
> We've got our transponder antenna mounted in the ventilation air duct
> in the nose. Works just fine. Plane is a Russia, with no carbon
> fiber.
> On 3 Dec 2003 14:26:39 GMT, wrote:
>
> >Can anyone (maybe a Dutch gliderpilot) offer advice
> >to fitting a 175watt Becker transponder to a Ventus?
> >This is new to us in the UK. Type of aerial and the
> >best location for it? Does a carbon fibre fuselage
> >give problems? I'm thinking of putting the aerial in
> >the wheel bay.
> >
> >
>
> Rosemary
>
> To reply by e-mail, remove the "Nospam" from my address

[Ian McPhee]

Also good article in "Antennas by Jim" by Jim Weir of USA where he
mentions to use a 5 1/2 inch disk as ground or other huge multiples.
Keep out of line of your main body but legs would be less of a worry
Ian McPhee
Australia

[Ruud Holswilder]

On 3 Dec 2003 14:26:39 GMT, Chris Marren
> wrote:

>Can anyone (maybe a Dutch gliderpilot) offer advice
>to fitting a 175watt Becker transponder to a Ventus?

Just now the Dutch authorities have decided tot postpone the
obligation to carry a transponder till 2008.
By that time mode-s will be the one and only standard.