Assuming that you also want the s spaces followed by a J as well, then
^\s{5}J\s.{22}\S
will do it. If there are multiple lines in the text that you are scanning, then you will also need to use 'multiline' mode so that the '^' will apply to the start of each line, not just the start of the text.
If you just want to find a non-blank in column 30, then
^.{29}\S
will work. If you want to match the characters in columns 30 to 35 then
^.{29}(\S(6})
Because you question is quite loosely worded, I may not have captured your requirements. If not, then try playing with the various components of the samples above, and if that is not enough, then get back with the exact requirements and some real sample text for us to test.
Also, please read the posting guidelines in the sticky note at the start of this forum for guidance on how to ask your question. I've tried to use generic regex commands so that this should work whatever your regex and language, but there are no guarantees.
Susan