Mantracourt Electronics Limited
T24-SAf Fast Strain Gauge Acquisition Module User Manual
16
Installation
Overview
Radio performance at microwave wavelengths is very dependent upon the operating environment; any
structure within the operating region of the radios will give rise to three effects:
Obscuration.
Obscuration will result in reduced range and occurs when an obstruction masks the line-of-sight
between radios.
Aberrations to the horizontal and vertical space patterns
. Distortion of these patterns may occur if
structures or objects are placed in the near or intermediate field of the antenna. The effect will be to distort
the coverage patterns, adversely affecting range and link quality.
Reflection.
Any object placed in line-of-sight of the transmit antenna will result in signals arriving at the
receiver by an indirect path. Degradation of performance due to reflection (multipath effects) appears as
reduced range or poor link quality.
Any of the above will cause poor RSSI figures, an increase in the packet loss rate and in extreme cases
complete loss of signal. Fortunately, if consideration is given to these effects at the integration stage then a
good quality link will be obtained.
Guidelines for product design:
When selecting materials for product enclosures, preference should be given to fibreglass, light coloured ABS or
Polypropylene; at the wavelength of 2.4GHz radio other materials will adversely affect the signal by
attenuation, refraction or change in polarisation.
If the application demands that the radio is fitted inside a metal enclosure then ensure that the specified
clearances are maintained around the antenna and design in a fibreglass RF window at least as large as the
clearance dimensions but ideally as large as possible.
RAD24i radios fitted inside a product should be oriented so that the chip antenna will be vertical when the
product is in its normal operating position.
Guidelines for installation:
When planning installations ensure that line-of –sight between nodes is maintained and that objects or
structures are kept at least one metre away from antennae wherever possible.
To avoid poor link quality between a RAD24i radio and a handheld device ensure that the RAD24i is mounted so
that the chip antenna is vertical. Improvement may also be obtained by altering the height above ground of the
RAD24i; a small increase or reduction in antenna elevation will often improve reception.
Range underwater is only a decimetre or so depending on packet rate. Best performance underwater is
obtained by using low packet rates and immersing water-proofed antennae rather than water-tight enclosures
containing the antennae.
