Standard refresh interval of SDT ( tables with info about channels and services ) spans each 4 hours regardless of changes,
new version number (rolling from #00 to #31) begin spooling:
1 am PDT
5am PDT
9am PDT
1pm PDT
5pm PDT
9pm PDT.
If there are any changes, new SDT will come any time.
Last days the time when new tables start spooling:
Time - sections - version
4/15/08
[01:00:16 am] 435 15
[03:10:16 am] 434 16
[05:00:16 am] 434 17
[09:00:11 am] 434 18
[10:40:11 am] 428 19
[01:00:12 pm] 428 20
[02:20:12 pm] 428 21
[05:00:12 pm] 428 22
[09:00:13 pm] 428 23
4/16/08
[01:00:13 am] 428 24
[03:10:14 am] 429 25
[05:00:13 am] 429 26
[09:00:14 am] 429 27
[09:45:14 am] 431 28
[01:00:15 pm] 431 29
[02:00:14 pm] 433 30
[05:00:15 pm] 433 31
[09:00:16 pm] 433 00
...