Yamato's radars
Posted: Sat Sep 20, 2008 4:00 pm
The Yamato was equiped with three different types of radar. None of these radars were firecontrol specific designs. A 10cm fire control design known as the Mk3Model2, developed from the Mk2Model2, never made it into operation before the end. These were the active radars installed:
Mk1Model3 This was a long range Air Early Warning design. It operated on 2 meters wave length with pulse widths of up to 10 micro seconds, and a power of 10kw. The Antenna was a dipole array hung off the tripod main mast aft of the funnel.
Mk2Model1 This was a general tactical radar used for both surface surveilance and air warning and operated on a wave length of 1.5 meters.These sets used the antennas mounted to the arms of the main 15 meter rangefinder apparatus. Musashi had one set of the Mk2Mod1 as early as mid 1942. During test shoots off Katsura Island in Sept 1942 the radar was always knocked out by the concussion of the 18" salvoes, that sent complaints to the Naval Technical Research Lab for a remedy. The radar was upgraded at least three times with power reaching 13kw in the later models. The range resolution was 450 meters. The range often listed is only 20km, but that may not be correct at least for a large target radar cross section such as a BB or a CV. In 1944, there were actually two sets of the Mk2Model1 installed with the antennas for each radar installed on the left hand and right hand arms of the main range finder. This is most interesting because it could have allowed a precise fix of an isolated target's bearing by maximizing the signals from the left and right hand radar sets. The horizontal beam width was wide however.
Mk2Model2 This was a centimetric radar operating on a wave length of 10cm. It was a general tactical, sea surveilance, and air warning set. This radar was first made operational in the summer of 1942. The transmitter was a cavity magnetron producing 2-5kw of power. The antenna wave guide windows were small round horns (looking much like fog horns), one for transmission and one for receive. The Yamato had two sets installed with the antennas installed on platforms extending from the left and right sides of the tower bridge structure. These horns are so small that they can't be easily seen in photos, or if noticed at all are often mistaken for fog horns or loud speakers. Brown says that it probably compared well to the early model British 10cm Type 271 radars without PPI. The range attainment listed in the literature vary widely from only 20km for a detecting a BB, to 34, 34.5, and 35 km for large surface ships. The 35km figure is plausable even with the low power and small antennas, if it used long pulse widths, as reported in some circles. Long pulse widths increase the illumination energy because the energy is the power multiplied by the pulse width, and because long pulse widths require much less band width at the reciever, essentially making the reciever much more sensitive. Since this was a general tactical radar fine precision wasn't required of it.
Mk1Model3 This was a long range Air Early Warning design. It operated on 2 meters wave length with pulse widths of up to 10 micro seconds, and a power of 10kw. The Antenna was a dipole array hung off the tripod main mast aft of the funnel.
Mk2Model1 This was a general tactical radar used for both surface surveilance and air warning and operated on a wave length of 1.5 meters.These sets used the antennas mounted to the arms of the main 15 meter rangefinder apparatus. Musashi had one set of the Mk2Mod1 as early as mid 1942. During test shoots off Katsura Island in Sept 1942 the radar was always knocked out by the concussion of the 18" salvoes, that sent complaints to the Naval Technical Research Lab for a remedy. The radar was upgraded at least three times with power reaching 13kw in the later models. The range resolution was 450 meters. The range often listed is only 20km, but that may not be correct at least for a large target radar cross section such as a BB or a CV. In 1944, there were actually two sets of the Mk2Model1 installed with the antennas for each radar installed on the left hand and right hand arms of the main range finder. This is most interesting because it could have allowed a precise fix of an isolated target's bearing by maximizing the signals from the left and right hand radar sets. The horizontal beam width was wide however.
Mk2Model2 This was a centimetric radar operating on a wave length of 10cm. It was a general tactical, sea surveilance, and air warning set. This radar was first made operational in the summer of 1942. The transmitter was a cavity magnetron producing 2-5kw of power. The antenna wave guide windows were small round horns (looking much like fog horns), one for transmission and one for receive. The Yamato had two sets installed with the antennas installed on platforms extending from the left and right sides of the tower bridge structure. These horns are so small that they can't be easily seen in photos, or if noticed at all are often mistaken for fog horns or loud speakers. Brown says that it probably compared well to the early model British 10cm Type 271 radars without PPI. The range attainment listed in the literature vary widely from only 20km for a detecting a BB, to 34, 34.5, and 35 km for large surface ships. The 35km figure is plausable even with the low power and small antennas, if it used long pulse widths, as reported in some circles. Long pulse widths increase the illumination energy because the energy is the power multiplied by the pulse width, and because long pulse widths require much less band width at the reciever, essentially making the reciever much more sensitive. Since this was a general tactical radar fine precision wasn't required of it.