Dave,
In the "Through the Looking Glass" section of the website, there is a picture of what is said to be the S-42 fitted with what is obviously the slotted antenna of SJ-1 radar. Flanking it are what appears to be to S-18 subs, also with the SJ-1 radar antenna. Do you or your cohorts know when that pic was taken? I've pored through the patrol reports for the S boats and can't find any mention of SJ-1.
The pic in question is this one:
http://www.pigboats.com/subs/s42conn.jpg