Leica mojoRTK How-To Manual page 2

High gain antennas on the base and/or the console can improve
communications. High gain antennas do not provide any extra power
when transmitting or receiving. What they do is transmit into and listen
from a more directed field resulting in stronger signals to and from that
direction. It should be noted that there are cases where higher gain
antennas can cause problems with radio performance. Points to note
regarding high gain antennas on the base/console radio antennas:
You should avoid using a high gain antenna on the vehicle
when the vehicle is working on steep terrain (due to the effect
shown in Figure 3 later)
Also note that in some countries and regions higher gain
antennas are prohibited on certain radios or licenses may be
required to use them. When using high gain antennas it is
important to make sure that you are using the correct antenna
for the job. You should consult local communications
companies to guide you towards the right antenna.
Poor placement of the base station can result in radio reflections
which interfere with the direct signal. There are situations where the
base station can be placed in a position with a clear view of the sky for
good GPS reception but still be close to a tree, shed, silo, or with a hill
behind the base. The problem with having something behind the base
station is that the console can receive the direct signal from the base as
well as the signal reflected off the object behind the base. This can
cause interference patterns in the field which can be very disruptive to
the performance of the radio communications.
Use of good cables and connectors. When you are putting the
mojoRTK base station antenna at the top of a tower you should use
good quality cables so that the signal is not significantly weakened
before it reaches the transmitting antenna. Again, you should consult
local communications companies to guide you towards the right
equipment when extending RF cables. See the 'How To Guide' for fixed
base stations with external antenna.
Be aware of possible interference from other sources. Sometimes
the communications between the base station and the console may be
severely affected by radio interference from an external source or
possibly even another mojoRTK base station nearby. The first thing you
can try is to change the channel on the base station
have channels 0 to 3 to choose from with the European 868MHz
systems and 0 to 19 on the 900MHz North American and Australian
systems. Also note the following:
For more information
www.mojoRTK.com
Page 2/9 Document #1060 rev1.0
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