I found an interesting observation about the early use of SD RADAR in Blair's book, "Silent Victory": Pearl Harbor, December, 1941; First Patrols to Empire Waters":
". . . In addition to her Mark VI magnetic exploders, Plunger carried another secret weapon into combat: a primitive radar set known as the SD. The SD was new. It had extremely limited range, 6 to 10 miles. It was "nondirectional," useful primarily for detecting enemy aircraft. Its mast could be poked up before the boat surfaced.
Like many submarine skippers, (Dave) White was leery of the SD. In limited tests, he had found it temperamental and unreliable. It gave off a powerful signal which could be picked up by Japanese RDF stations. Unsparing use of the SD, White believed, was tantamount to breaking radio silence. It would make his presence known and reveal his exact location. The Japanese could send antisubmarine vessels or aircraft to attack him and route their shipping well clear of him. White preferred to depend on alert lookouts for spotting Japanese planes."
Now I know why those pesky patrol/float planes always seem to be vectored right at me - THEY ARE!
The SD RADAR is always on in the game while surfaced, and I regularly do a search for aircraft with extended antenna at periscope depth before surfacing.
If I spot a plane while submerged, I just lower the antenna and dive to around 150'. If I spot a plane on the surface, then I crash dive and make a 90 degree turn to right or left at 40' and continue down to 160' at flank speed, then slow to 1/3 ahead and continue down to below 200'. The planes do sometimes drop bombs or DCs, but I haven't been hit yet.
This is the first time I've seen the RDF triangulation problem noted anywhere.