Did anyone ever consider putting radio homing beacons like those used on aircraft carriers on cruisers or battleships (or U-Boats) during World War II so that friendly fighter planes (or bombers) could find them at night and already be overhead to provide air cover (or attack a convoy) at dawn?
The scenario I'm imagining is around 2:00AM on August 9, 1942, a bunch of specially trained Zeros and G4Ms take off from Rabaul, form up using their running lights, fly east, and home in on the beacon once they detect it. The sun comes up and Admiral Turner finds his transports sharing Ironbottom Sound with Admiral Mikawa's cruisers and a squadron of G4M torpedo bombers with a swarm of Zeroes protecting the lot while all of Admiral Crutchley's cruisers are at the bottom of the sea. (alternatively, this happens on October 13, only now there's two Kongo class battleships hanging out in Ironbottom Sound instead)
One of the main reasons Mikawa turned around instead of hitting the transports was because he didn't think he could reform his squadron, sink the transports, and get out of range of Fletcher's carriers before the sun came up and exposed him to air attack since he didn't know Fletcher had already pulled out. Pulling something like this off would at least give him air cover during his withdrawal. Did anyone ever try it, did no one think of it, was the technology just not there yet, or was there some other reason it wasn't done (to my knowledge at least)?
The technology for radio beacons for night navigation existed, and was already in use before the war, with the Lorenz system installed at Tempelhof airport in Berlin in 1932. Lorenz was too short-ranged to be used for navigation for night bombing over England, but new systems were developed early in the war, and counter-measures to stop them (this was the "Battle of the Beams" of 1940 and 1941).
Apart from the immediate problem of no such system being available to the Japanese to guide aircraft from Rabaul to Guadalcanal, nor trained pilots to make use of it, it wouldn't have been useful. The problem was that Guadalcanal was at the extreme combat radius of the A6M2 Model 21 Zero. They could reach Guadalcanal (and therefore could be used to escort bombers), but they couldn't stay there for long enough to provide air cover for Japanese ships there. The Zeros flying from Rabaul to Guadalcanal often flew without radios to reduce weight and therefore increase range, which made them less likely to run out of fuel before getting back to Rabaul. The newer, more powerful A6M3 Model 32 Zero (AKA Hamp) had thirstier engines and less range, and after their first few missions to Guadalcanal demonstrated that they were unlikely to make it back, only the A6M2 Model 22 was used.
The G4M Betty had much greater range than the Zero, and could loiter over Guadalcanal, but would have been at the mercy of US fighters. The G4M crews who flew missions to Guadalcanal got a rude shock from the defensive firepower of US ships - even the transports were typically armed with 4 40mm AA guns (usually 2 twins) and 10 to 18 20mm AA guns, together carrying more light AA guns than HMS Prince of Wales and Repulse when they were sunk the year before.
When Rabaul first received news of the US invasion force on the 7th of August, the immediate response was an air attack. Coincidentally, aircraft were already armed for a raid on Milne Bay in New Guinea, and these aircraft were sent to Guadalcanal instead. This included 9 Vals for which it would be a one-way mission, as they lacked enough range to return (and the same applied to the A6M3 Model 32 Zeros which flew on the raid). The G4M Bettys, armed with bombs for the Milne Bay raid, dropped their bombs from high altitude and kept clear of effective anti-aircraft fire, missed their targets, and 5 of 32 Bettys were lost to defending fighters. (One Val hit the destroyer Mugford with a bomb.)
The next raid was the next day, on the 8th, and this time the Bettys carried torpedoes. 29 Bettys were available for the raid, 9 more having arrived on the 7th making up for the day's losses. Of these, 24 reached Guadalcanal, with 3 of these being shot down by fighters before beginning their torpedo attack runs. The quick-firing light AA, especially the plentiful 20mm guns, shredded the incoming Bettys; 5 of them returned to Rabaul. One destroyer, Jarvis, had been hit by a torpedo, and was badly damaged, and one Betty crashed into the transport George F. Elliot, and was scuttled soon after.
Even without defending fighters to stop them, a loitering force of Bettys might not have been able to achieve much against the US ships. If the US carriers were still present, Zeros could not have provided air cover against them, and Bettys would have faced both fighters and AA guns. Rabaul could attempt to hit US ships, but could not protect Mikawa even if radio beacons and pilots trained for night operations were available. Mikawa's retreat might or might not have been a mistake, but it wasn't a decision that could have been meaningfully affected by Rabaul.