User's Manual

54 MDS Mercury 16E Technical Manual MDS 05-6302A01, Rev. B
GPS Cabling & Antenna
The antenna to be used with the transceiver’s built-in GPS receiver
should be a 16 or 26 dBi active antenna designed for the GPS satellite
band. The GPS antenna connector delivers a 3 Vdc supply to power the
electronics in the active antenna.
6.7 Conducting a Site Survey
If you are in doubt about the suitability of the radio sites in your system,
it is best to evaluate them before a permanent installation is underway.
This can be done with an on-the-air test (preferred method); or indi-
rectly, using path-study software.
An on-the-air test is preferred because it allows you to see firsthand the
factors involved at an installation site and to directly observe the quality
of system operation. Even if a computer path study was conducted ear-
lier, this test should be done to verify the predicted results.
The test can be performed by first installing a radio and antenna at the
proposed Base Station (BS) site (one-per-system). Then visit the Sub-
scriber site(s) with another transceiver and a hand-held antenna. (A PC
with a network adapter can be connected to each radio in the network to
simulate data during this test using the PING command.)
With the hand-held antenna positioned near the proposed mounting
spot, a technician can check for synchronization with the Base Station
(shown by a lit LINK LED on the front panel) and measure the reported
RSSI value. (See “Antenna Heading Optimization” on Page 56 for
details.) If adequate signal strength cannot be obtained, it may be neces-
sary to mount the station antennas higher, use higher gain antennas,
select a different site or consider installing a repeater station.
6.8 A Word About Radio Interference
The transceiver shares the RF spectrum with other services and devices.
As such, near 100% error-free communications may not be achieved in
a given location, and some level of interference should be expected.
However, the radio’s flexible design should allow adequate perfor-
mance as long as care is taken in choosing station location, configura-
tion of radio parameters and software/protocol techniques.
In general, keep the following points in mind when setting up your com-
munications network.
• Systems installed in rural areas are least likely to encounter interfer-
ence; those in suburban and urban environments are more likely to
be affected by other devices operating in the same spectrum.
• Use a directional antenna at remote sites whenever possible.