User's Manual

USER MANUAL 1.34

STM 300 / STM 300C / STM 300U

4.6 Positioning of the whip antenna

Positioning and choice of receiver and transmitter antennas are the most important factors

in determining system transmission range.

For good receiver performance, great care must be taken about the space immediately

around the antenna since this has a strong influence on screening and detuning the an-

tenna. The antenna should be drawn out as far as possible and must never be cut off.

Mainly the far end of the wire should be mounted as far away as possible (at least 15 mm)

from all metal parts, ground planes, PCB strip lines and fast logic components (e.g. micro-

processors).

Do not roll up or twist the whip antenna!

Radio frequency hash from the motherboard desensitizes the receiver. Therefore:

 PCB strip lines on the user board should be designed as short as possible

 A PCB ground plane layer with sufficient ground via is strongly recommended

 Keep antenna away from noise generating parts of the circuit. Problems may especially

occur with switching power supplies!