Step 8. Are You Being Jammed - ashtech Z-Xtreme System Manual

Not within range specifications
Move within range. Either move closer to the base system, or move the base
system closer to you.
Within range specifications
Move closer to base to test system. Since radio range is difficult to predict
due the varying effects of local conditions, try moving closer to the base in an
attempt to resolve the problem.
If by moving closer you find that the rover radio begins to receive data, the
previous location is out-of-range of the radio system. You will need to elevate
the base radio antenna or move the base to a location closer to you to solve
the problem.
Go to step 8 below if the problem is not yet resolved.

Step 8. Are you being jammed?

When working with UHF/VHF radios, it is possible that the frequency you are using is
being shared with other people in your vicinity. Traffic on this frequency can interfere
with the rover system's ability to receive data from the base. The effect may be no
reception of base data or intermittent reception of data. Both are detrimental to
proper operation of the RTK system. Interference is more a problem with UHF/VHF
radios than with spread-spectrum radios.
There are two methods to determine if there is traffic on the frequencies you wish to
use. The best method is to acquire a handheld scanner and to listen for traffic on the
frequency you plan to use. The second method is to observe the receive LED on the
base or rover radios. The base and rover radio will receive any traffic on the fre-
quency they are set to causing the receiver LED to flash. This is best done before
setting up the base system to transmit data. Any flashing of the receive LED indicates
some traffic on your frequency. If the base is transmitting data, the rover receive LED
will flash once per second if receiving data from the base. If you observe more ran-
dom flashing of the receive LED, this is an indication of traffic on the frequency other
than the base transmissions.
Not being jammed
Go to step 9 below.
Being jammed
1. Lower sensitivity of rover radio. Some field application software packages let
you change the sensitivity of the rover radio. If your software has this
capability, lower the sensitivity of the rover to medium or low. If the traffic on
your frequency is not strong in power, lowering the sensitivity of the rover
82 Real-Time Kinematic Surveying