From: John Bampfylde, INTERNET:jbamfyld@netlink.co.nz
Cruising through past messages on aerials has only brought on more
confusion, so I thought a new set of questions were required:
The transponder aerial is a stubby little creature with a ground plane of 8
inches (?) diameter.
Q1: Am I right that the aerial should point vertically downwards?
YES
Fibreglass is transparent to radio waves, and therefore for good looks, low
drag and less breakable bits the aerial should be inside the fuselage.
Q2 Is the optimal position for the aerial near the bottom of the hull?
YES . . . BUT NOT AS TRANSPARENT AS YOU MIGHT LIKE
If the aerial points downwards, the groundplane will be a horizontal dish a
few inches (the length of the aerial) above the fuselage hull floor.
Q3 Have people built a 'shelf' in the fuselage to mount the aerial?
YES . . . I'VE SEEN IT DONE EFFECTIVELY IN GLASAIRS
The Aeroelectric connection talks about using copper tape as the
groundplane, and this tape can be glassed into the shelf (or hull if the
aerial sticks out).
Q4 Have most people followed this process or bought a ready made groundplane?
FOR THIS APPLICATION, MAKE THE GROUNDPLANE FROM AN ALUMINUM OR COPPER
DISK 5.2 INCHES IN DIAMETER (SAME RADIUS AS HEIGHT OF ANTENNA).
Regards,
Bob . . .
AeroElectric Connection
////
(o o)
| |
| Go ahead, make my day . . . |
| Show me where I'm wrong. |
72770.552@compuserve.com
http://www.aeroelectric.com
|