User's Manual Part 2
Troubleshooting
G
ATEKEEPER SYSTEMS INC.
2007
CART CONTAINMENT MANUAL
Page 73
Setting Up a Test Loop
When setting up a test loop, you bypass the perimeter antenna and attempt to lock a cart wheel using a small
local antenna hooked directly to the CentralTransmitter (CT).
1. Power off the CT by pulling the plug from the wall outlet or de-energizing the circuit breaker at the panel.
2. Disconnect the perimeter antenna terminals from the terminal block.
3. Create a small local loop by connecting 10-15 feet of 14AWG antenna wire to the antenna terminal blocks.
4. Make sure the Field Strength Adjustment potentiometer knob is turned all the way to zero (0).
5. Power up the CT.
6. Place a cart with a working Gatekeeper wheel about three (3) feet from the loop.
7. Slowly turn up the Field Strength Adjustment knob and listen for the sound of the wheel beginning to lock.
8. If the wheel has not locked by the time you reach about a quarter turn on the knob, the CT probably needs
to be replaced. It is usually not a good idea to turn the field strength any higher, as you may risk locking
carts in nearby store areas.
9. When finished, return to the Main Troubleshooting Flow Chart on page 66.
Coupling
Definition: Coupling is the association of two circuits or systems in such a way that power may be transferred
from one to the other.
In the context of Gatekeeper Systems, coupling may be present when the 7.8 kHz signal transfers from the
antenna cable to surrounding conductive materials. Conductive materials can include conduits, data cables,
pipes, and even moist ground. When the antenna crosses the path of any conductive material a signal is coupled
onto this material. The degree of coupling is determined by how efficient a conductor the material is and how
much output is being generated by the Gatekeeper CentralTransmitter.
A drain pipe (medium efficiency conductor) in the ground will absorb the signal but will travel only a small
distance. A conduit with conductors inside (good conductor) will carry the signal much further; if the circuits
inside the conduit are energized and carrying current, the signal will carry even further still. If the antenna path
runs parallel to the conductive material within the field of the signal, the coupling is stronger than if the paths
cross.
The best way to avoid coupling is to eliminate it in the installation process. By following the installation steps in
the manual you will avoid a high percentage of coupling issues. In some instances coupling cannot be detected
until the installation is complete. Due to the construction and remodel of retail establishments it is impossible to
foresee all coupling scenarios. It is in dealing with these situations that the following troubleshooting techniques
should be applied to eliminate this phenomenon.
Tools you will need:
• SmartKey GS
1.1
and GS
2
• Toner and Amplifier,
• Cable Tracker,
• Wheel and CartKey.
1. When you arrive at the store, find out from store personnel in which area(s) of the store or parking lot the
carts are locking and if it is occurring on a regular basis.
2. Take a cart from the store’s fleet and a matching test wheel from your stock, and any test device you may
have for this system. Some stores have a mixed fleet. The most common is GS
1
mixed with GS
1.1
. The GS
1
is the most sensitive wheel and should be your test wheel. A Smart Key will work with the GS
1.1
and GS
2
. An
inductive amplifier will work on all circuits if there is not a lot of electrical noise.