Operations Manual

OPERATIONS 4-10
O&M of the MCC-545B PACKET DATA RADIO
12/2000
SYNTH,ON
You can then display/set the TX and RX frequencies using the following command:
FREQ{UENCIES{,aaaa,bbbb}}
where: aaaa = Tx Frequency (e.g., 4053 for 40.53 MHz)
bbbb = Rx Frequency (e.g., 4153 for 41.53 MHz)
IMPORTANT
Componentry in the MCC-545B limits the usable frequency range to a 2 MHz bandwidth. If
frequencies are to be changed outside this bandwidth, hardware modifications must also be made
to the MCC-545B.
If the synthesizer is unable to establish phase-lock when the SYNTH,ON command is entered,
the MCC-545B will respond UNLOCKED to the request and turn off the TX key. It will try
once a minute thereafter to establish phase-lock. If it fails, the message Synthesizer unlocked
will be displayed; if it succeeds, the MCC-545B will respond LOCKED and turn on the TX key.
4.2.9 Defining Data Relays
Performance at meteor mode Remote units having poor communication paths with a Master
Station due to ambient noise conditions, etc., can be enhanced by using an MCC-545B PACKET
DATA RADIO located in a quiet location line of sight with the Remote units as a data relay.
When used as a data relay, the 545B will concentrate data reports from one or more Remote units
and forward them to the Master Station.
When used as a relay, the MCC-545B must be defined as a Master Station and the Remote units
to be relayed use the relay as their preferred Master. The relay will receive MCC-550C sensor
data GROUP reports (see MCC-550C Operations Manual), repackage them and forward them to
the Master Station. A relay unit can handle up to a total of sixteen GROUP reports. These
reports can be in any combination; i.e., four groups from each of four Remote units, one group
from each of sixteen Remote units or any combination in between. Substitution tables must be
established in both the relay unit and also the Master Station to manage the relay function.
When a designated GROUP report is received at the relay, it will substitute its own ID and group
number in the report as defined in its substitution table and forward the data to a 520B Master
Station using 550C RF format rather than standard 545B message format. When relayed data is
received at the 520B, it will reconstruct the original data report based on its own substitution
table and route the report as required.
The following command is used to define entries in the substitution table for a relay unit: