Microhard Systems IP-921 Operating Manual page 157

IP9xx Series
7.0 Installation
Frequency
The 900MHz frequency range is not effected by rain to any signifi-
cant degree, and is also able to penetrate through foliage and
‗around obstacles' to a certain degree. This being the case, some
may choose to scrimp on the physical deployment, particularly when
it comes to antenna (tower) heights. Path calculations provide re-
sults which specify ‗required' antenna heights. For cost savings and
in taking advantage of the characteristics of the 900MHz frequency
range, sometimes the height requirements are not adhered to: this
may result in unreliable communications.
Power Requirements
The IP Series accepts a range of DC input voltages (keep in mind
that supply current requirements must also be met). In some deploy-
ments, power consumption is critical. Power consumption for the IP
Series may be minimized by reducing the transmit power, given the
receive sensitivity of the distant modem.
Interference
The frequency hopping spread spectrum (FHSS) operation of the IP
Series modem most often allows it to work well in an environment
within which there may be sources of inband interference. Fre-
quency Restriction is a built-in feature which may be utilized to avoid
specific frequencies or ranges of frequencies; the built-in Radio
Channels Noise Level tool may be used to identify areas of potential
interference. Cavity filters are also available if required: contact Mi-
crohard Systems Inc. for further information.
© Microhard Systems Inc. CONFIDENTIAL 157