SkyHunter406 SKYHUNTER 406 HF - Manual (Page 33)

MANL:INS:SH:X:XX August 8 ,2013
Rev 25
6-15
6.5.4 Ground Plane Requirement (Wood/Fabric and composite aircraft)
The following has been reproduced from AC 43.13-2B, please refer to for a more up to date
version.
6.5.4.1 When the antenna is not mounted to a
conductive surface capable of providing a
required ground plane for operation, a ground
plane must be fabricated.
6.5.4.2 Most antennas require a ground plane of
approximately 24” by 24”. While the rule of
thumb is to provide a minimum of ¼
wavelength of the operation frequency, larger
is better and ground plane symmetry is critical.
Gaps in antenna coverage or performance may
occur if a ground plane is not symmetrical.
6.5.4.3 Wire mesh is the best material to use when a
solid plate is not practical. Heavy aluminum foil
can also be used. In all cases, electrical
continuity from the ground plane to airframe
ground is essential.
6.5.4.4 Be sure the ground plane is well attached to the
airframe with cement or epoxy if not otherwise
supported. This will prevent noise problems or
erratic operation that could occur as an
antenna base is separated from its ground
plane. This may distort antenna coverage or
operation.
6.5.5 Ground plane sizing
The ground plane should be as large as possible but when size is restricted, the following should
be used as a guideline.
Frequency Wavelength ¼ Wavelength
121.5 Mhz 97 inches 24 inches
406.037 Mhz 29 inches 7 inches
Therefore the ground plane should be at least 24 inches in diameter.