4: Radio Programming
4-18 PRC1099A-MSOP
Net Self
Note 1
Slot numbers are determined by the number of stations on the net. Each station
is assigned a separate slot number by the Net Control Station. Slot 00 is
preassigned to all net members and used to tune their transmitters for
emergency purposes.
Net Self
Note 2
Slot timing is the time required by a radio to process the network call and the
network response. To determine the slot time, each ALE word is equal to 3
characters (392 ms). For example, a 15 character ID requires 5 ALE words
(1.96 sec).
It is recommended that each net member set its slot time to a value that allows
room for the largest combination of net responses. The length of each response
is determined not only by the length of each member’s own ID, but by the
length of the ID of the calling station. This gives any net member the capability
to call the entire net. Use the largest ID on the net to begin determining the slot
time.
The example below describes the process of determining a slot time.
1. Determine the IDs for all net members.
Example Net IDs: ABC, DATRONWLD, DEF, XYZ
2. Determine the largest ID on the net.
Example: DATRONWLD
3. Convert the largest ID on the net to ALE words.
Example: DAT RON WLD = 3 ALE words
4. Calculate the time by multiplying the ALE words by 392 ms.
Example: 3 x .392 = 1.18 seconds. Largest ID on the net = 1.18 seconds
5. Double this result to compensate for both the initial call and response.
Example: 2 x 1.18 sec = 2.36 seconds
6. Add another 1.18 seconds to allow for the repetition of the destination
address during the call.
Example: 2.36 + 1.18 seconds = 3.54 seconds
7. Add 392 ms to compensate for receiving stations requiring a minimum
amount of dead air time to determine the end-of-transmission.
Example: 3.54 + .392 = 3.932 seconds
Total slot time for each net member = 3.932 seconds
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