I was going through the included documentation of FotRSU, I happened upon CapnScurvy’s paper on radar and sonar. I’m impressed with methodology he used to develop such authenticity. Now that I have a few months of ‘sea time’ under my belt and have used the radar extensively, I wanted to comment CapnScurvy’s superior modelling of the radar, especially the US SJ and SJ-1 sets.
I was conducting an intercept of a merchant during a heavy rain and high wave condition. Visibility was down to about 500 yds. The merchant was maneuvering in a classic ‘zig-zag’ to make a torpedo firing solution difficult. After tracking for several miles and determining his turn frequency, I had a solid bearing and range and I closed on the target. I considered a torpedo shot, but with the sea condition, broaching was almost certain. Instead, I called the gun crew to quarters. I had them open fire around 500 yds and the ship was on fire and taking water after about 12 rounds. A lot of work for a 1400 ton freighter. Tonnage is tonnage!
While the radar was painting the target, pip’s faded in and out due to the heavy rain. Exactly what a real radar set would do! I was using the ‘A’ scope frequently to verify range. On the display of the ‘A’, the triangular pip would shorten and become hard to see in the background noise. Again, exactly how a radar set IRL would behave. This is pretty cool! Radar sets, up until in introduction of computers, used a simple Signal to noise cancellation circuit. The algorithm: Signal+Noise/Noise. I am really amazed with how true this model performs.
The SJ units were superbly designed radar sets and very much ahead of it's time! It’s operating frequency is 3 GHz (S band) which makes the set a true microwave design. As the electromagnetic spectrum goes, the higher the frequency, the more directional and focused the energy is. As compared to the German FuMO 29 & 30 sets which operated at 368 MHz: the SJ is a laser pointer and the FuMO is a flashlight!
The range accuracy of the SJ was 25 yds +/- 0.1%. Bearing +/- 0.3%. Compared to the FuMO 30: bearing 100 m +/- 5°. This system is perfect for accurate gun laying and torpedo solutions! Germany did a considerable amount of R&D radar in the early 30’s. It fell by the wayside due to the attitude of ‘is this really necessary?’ Realizing their error, they spent the rest of the war playing catch up while the allies really made effective use of this system.
Enough babbling! I just wanted to send a Bravo Zulu to CapnScurvy and the rest of the FotRSU team for such a great mod!