Data Sheet

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tag from idle to track or from monitor to track any other active tags will
disappear from the display, this allows you to concentrate on tracking the
selected tag.
Low Battery Alarm
Each time the locator communicates with a tag, the tag sends back its battery’s
charge status to the locator. If the tag’s battery is low then the Low Battery
message will appear on the display and there will be one short beep once every 5
seconds. At the time that the low battery alarm is displayed the tag still has
enough battery capacity to stay in monitor mode or idle mode for about two more
days or track mode for about 8 hours. If you are not using the locator to monitor
your tags then you should check the battery status of each tag once a week by
turning the tag off and back on and observing the number of times the status light
flashes when the tag starts up. 1 flash means a low battery condition, 2 flashes is
half charged and 3 flashes indicates more than half charged. You can also check
to make certain the tag’s battery is not low by putting it into track mode from the
locator and checking to see if the Low Battery icon is shown on the locator’s
display.
Notes on Radio Frequencies
The Marco Polo system uses frequency hopping spread spectrum (FHSS) on 50
frequencies between 902.5MHz and 906.5MHz. The maximum transmission time
on a single frequency is 50msec.
When the tag is in idle mode (status light is flashing once every 10 seconds) it
does not transmit any RF energy - it only switches on its receiver once every 10
seconds to search for a signal from the locator. In this mode the tag can be co-
located with other RF transmitters and receivers without fear of the tag
interfering with those systems.
To achieve the maximum range of operation of the Marco Polo system it is
important that strong radiators in the 900MHz band are kept away from both the
locator and the tag. If battery powered transmitters are used in the 900MHz band
near the tag then it may be necessary to wait until the battery power is depleted
before searching for the tag. When possible, use the 2.4GHz or 5.8GHz bands for
equipment that will be nearby the tag and switch off any 900MHz transmission
sources near the locator.