SEA 235, Operator'S Manual

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GENERAL OPERATIONS
3
UNDERSTANDING CHANNEL MEMORY
CHANNELS
Nearly 1000 frequency pairs are stored as permanent channels in the SEA 235.
These channels are recalled by their assigned ITU or SEA channel number. ITU
numbers are known internationally and include all duplex frequency pairs
starting at 4 MHz and ending with 25 MHz. SEA numbers are assigned to those
frequencies that do not have an assigned ITU number. Currently all 2 to 3 MHz
frequencies and all simplex frequencies are assigned SEA channel numbers.
It is important to note that not all radios use the same channel numbers for
simplex or 2 to 3 MHz frequencies. Some radios use an “A”, “B”, “C” channel
assignment for frequencies not assigned an ITU channel number. For example,
if you refer to the SEA simplex channel 451 during communications, the person
you are communicating with may not have a channel 451. Their radio may have
the same frequency (4146.0 KHz) assigned to channel “4A”. For reliable
communications, always refer to the frequency when referencing simplex
channels or frequencies below 4 MHz.
BINS
In addition to the permanent memory, 200 user programmable channels known
as bins have been assigned for “scratchpad” memory. Approximately 170 of
these 200 channels have been programmed by SEA but may be changed at any
time. Bins may be programmed with any frequency, mode of transmission and
given a name tag besides a bin number.
SCAN CELLS
Consecutive bin numbers that have the same first three characters in their name
tag, are known as “scan cells”. SEA has programmed 170 of the 200 possible
bins into 23 different scan cells. Scan cells may be as short as one bin or as long
as 200 bins but should be kept to a reasonable length for scanning efficiency.
Each scan cell is organized with frequency pairs that are related to one another.
For example, bins 13 through 30 have been programmed with frequencies
assigned to the coast station KMI. Since the name tag’s first three characters are
“KMI”, and the bins are consecutively numbered, the bins may be scanned as a
group. If the bins do not have the same first three characters, the scan cell will
be split into two different cells. For instance, if bin 20 is renamed to “SEA 1”,
the KMI scan cell will be split into two cells. One cell will contain bins 13
through 19, while the other cell will contain bins 21 through 30. Bin 20 will be a
single channel scan cell called “SEA”. Scanning “KMI” could be done by
scanning bins 13 through 19
OR
bins 21 through 30 but not both at the same
time.
Care should be given that a scan cell is not split unintentionally. Bins that will
not be scanned can be given any descriptive name tag.