User Manual
Confidentoial
Patent #’s 7,420,471
5,939,986 and 6,810,353
Patent Pending
Page 4 of 9
Strata Proximity Systems Underground PAD Users Manual v1.0
Confidential and Proprietary
September 1,
2011
If the PIC determines that the received field is above the threshold level, it sends a logic signal
and data to an internal RF Transmitter Board. The RF Transmitter Board contains a LINX TXM-
916-ES transmitter Integrated Circuit. The TXM-916-ES generates and frequency modulates a
916.48 MHz carrier with the data sent from the PIC microcontroller on the PAD System Board.
The RF Transmitter board has no alignment procedure as the TXM-916-ES treanmitter has a self
contained crystal controlled PLL oscillator. This transmitted 916.48 MHz signal will alert the
vehicle or machinery that generated the 73 kHz field that was received, that this particular
Underground PAD unit is coming within an unsafe distance of the vehicle or machinery. If the
PIC determines that the 73 kHz field strength is below the threshold level, it will cause the RF
Transmitter to transmitt the unit’s status and identification data once every 10 seconds.
Along with generating the RF signal to alert the machinery or device, the Underground PAD will
also alert the person wearing the PAD with both an audible sound and a visual indicator that
they are in an area that is too close to the vehicle or machinery. The audible and visual
indicators are located on a Warning Unit Board which is also within the Underground PAD.
1.2 Frequency of Operation
The PAD will transmit as a frequency of 916.48 MHz in the ISM Band.
1.3 Approvals
1.3.1 MSHA Approval
The MSHA approval number is HA-PAD-2100.
1.3.2 Pennsylvania Approval
The Pennsylvania approval number is BFE69-11.
1.3.3 West Virginia Approval
The West Virginia approval is expected Q4 2011.
1.4 Label Information
The Underground PAD label is located on the front center of the unit. A picture of the Strata
label and MSHA label is below: