Installation Guide Part 3

NGL FX Installation Manual Rev. * 71 of 84
2. Racks – Clothing racks would exhibit the same affect as door frames. When the racks
move false alarms could occur.
Just about any metal structure close to our system could have the same affect as the two items
listed above. Other sources of this type noise could be merchandise close to, or passing through,
our pedestals. In most cases merchandise is the hardest items to identify and because they are
meant to pass through our pedestals, could be the worst offender of false alarms.
The idea is to reduce the affects of the noise above by either reducing the noise at the source or
desensitizing our system to the source of noise. The following sections will give some guidance
for tuning when either type of noise is present.
Note
During installation leave the Sam Option "Enable Sweeper Immunity" off until the system is tuned so that that DMS A
view will accurately show any interfering noise characteristics. Once the system has been tuned, this option can be
set.
Analog View
The Field Service DMS application displays live data to assist the technician in adjusting the
Reader for optimal performance. The Analog View is the best display for observing short duration
noise and stationary environmental resonances. The signals from each pedestal (PAB and SAB)
are displayed left to right. Because of the nature of the ECO system, both 2-3 loops for each
pedestal are combined in each view with each port adjustment affecting both loops in a pedestal.
In the Analog View, there are a total of four different points within the signal processing chain that
can be viewed. The Filter View switch controls which level of signal processing can be displayed.
Typical Tuning Procedure
A typical environment would be one free of random noise and resonances.
This may involves adjusting TX Power, RX Gain and RX Hardware gain for the PAB and SAB in
the following order:
1. Adjust TX Power for PAB and SAB pedestals according to the regulation maximum. For
best performance, TX Power should be set equal for both pedestals.
2. Flip to View D and adjust RX Gain individually for each pedestal, until the noise floor
disappears under the Analog View.
3. Flip to View C and adjust RX Gain individually for each pedestal, a few more notches
down until the background resonances (if any) just about disappear. Because of the
natural resonance for the TR4215, the view should look like figure 40. The RX Hardware
gain in most typical cases will not need to be adjusted and should be set to 31.