Astro Fade Tolerance; Conventional Talkgroup Operation - Futurecom PDR8000 Manual

o If a common antenna is used for transmit and receive, then a duplexer is typically
employed to provide the needed isolation between the Tx/Rx paths.
•
In a half-duplex configuration:
o If separate transmit and receive antennas are used, a sufficient physical antenna
separation is required to provide the needed isolation.
o If a common antenna is used for transmit and receive, then the transmit/receive
isolation must be provided by either a duplexer, or other circuitry that can break
connection to the receive path during a transmission.
o A standalone PDR8000 has internal circuitry used to isolate transmit and receive
paths. When the external transmit Booster Pack is added, the PDR8000 can
provide control for an antenna switch located in the Booster Pack to provide the
needed isolation.
o A configuration parameter is provided in the Futurecom Repeater Configurator
(FRC) to control the operation of the Antennal Switches in PDR8000 and Booster
Pack for half-duplex channels. Antenna Switch control logic should be set to
Enabled for single-antenna, no duplexer operation, and Disabled for operation
with two antennas or a duplexer.
•
In a simplex configuration:
o Simplex operation utilizes the same antenna for both transmit and receive
operation.
o A standalone PDR8000 utilizes its internal circuitry to isolate transmit and receive
paths. When the external transmit Booster Pack is added, the PDR8000
provides control for an antenna switch located in the Booster Pack that keeps the
Booster amplifier in-line during a transmission, but bypasses the Booster
amplifier during receive.
PDR8000 has an external Auxiliary port, which provides a control mechanism between the
PDR8000 and a Booster Pack, as needed for some of the scenarios explained above (see
example hardware topologies in 2.1.3 and 2.1.6).
6.20 ASTRO F
When receiving a digital P25 RF signal, PDR8000 continuously determines whether an ongoing
transmission is being received. The loss of a certain number of consecutive ASTRO
superframes is treated like the end of a transmission. Due to environmental factors in the area
surrounding the PDR8000 antenna, certain fade conditions may occur which cause the RF
signal to temporarily drop out. PDR8000 has a configurable ASTRO Fade Tolerance
configuration parameter to provide a means of setting sensitivity to lost packets before the
PDR8000 assumes that a transmission has ended.
6.21 C
ONVENTIONAL
In some cases, multiple agencies or user groups may share a transmit/receive channel, and yet
require the conversations from each group to be heard only by other members of that group.
The P25 concept of Conventional Talkgroups allows this sharing of the physical channel, and
provides a level of group partitioning of the voice traffic. This is similar to the way that PL/DPL
is sometimes used on analog conventional channels.
2021-11-15
T
ADE OLERANCE
T
ALKGROUP
PDR8000® Portable Digital Repeater Product Planner
O
PERATION
Document 8K088X02 R5.0
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