New to radar (PPI and A-Scope)

[HertogJan]

I finally made it to July 42 and been offered a new sub.

USS Tambor SS-198 has been assigned to me and before leaving dry-docks it's been fitted with a 5" Bow mounted gun, Twin 20mm AA gun and surface radar :smug:.

Errrrrr...:hmmm: uhmmmm, I have no idea how to use the radar, the PPI in relation with the A-scope is something totaly new to me :oops:.

If undertood correctly, PPI give you targets bearing.

This below gives you range but what's what?
Could someone please explain this to me in very simple terms, thanks

0__________15__________30__________45__________60 (x 000y) :06:
|
|_____4_____8____12____16____20____24____28____32 :06:
|
|_________1000________2000________3000________4000 (M x 100):06:

[in_vino_vomitus]

The radar screens have been tweaked in various mods, so depending on what - if any - mods you're running will depend on the screen you see.

PPI is pretty straighforward, but without [for want of a better term] range rings you need to refer to the A scope.

The scale on the vanilla A scope is logarithmic, so when estimating distance with it, bear that in mind. OTC makes radar far more user friendly, and the 3D tdc mod in TMO includes a precision mode on the A-scope that once again, makes accurate ranging possible. The display you're illustrating looks like OTC.

Anyway - you have multiple scales, one for each range bracket on the range selector switch. You rotate the beam until you have a blip on the PPI and a spike on the A scope, and the position of the spike, on the appropriate scale, gives you the range. In your illustration, the top scale would be 0-60K [yards] the middle would be 0-32K and the bottom would be 0-4K [I suspect the middle scale should have X000 next to it, and the bottom scale doesn't need a multiplier]

[CapnScurvy]

HertogJan, you should tell us what mods you're using (although I know this answer quite well).

Optical Targeting Correction (http://www.subsim.com/radioroom/showthread.php?t=181172) puts these range marks onto the A-Scope radar screen to correct the stock games attempt at having nothing more than "eye candy" for radar use. Using the stock game, the A-Scope range ruler has the ranges wrong. You'll not come close to getting a range estimate using the stock A-Scope scale. To correct it, the three range lines you're asking about were "added" to the scope with the OTC mod. Depending on which radar power distance you select (with the switch below the screen), you will read the "spike" return at one of the three different range scales on the scope.

The three different "ranges" for the A-Scope radar are 4,000 yards, 32,000 yards, and 60,000 yards. The 60,000 yard distance is read off the top line, the 32,000 yard scale is in the center, the 4,000 yards distance is read on the lower line.

http://i175.photobucket.com/albums/w132/crawlee/USA-Scope.jpg


It's impossible to remove the stock scale line at the very bottom of the screen, so ignore it (although with it, you can see just how much of an error it gives in range to a target compared to OTC's correction).

With the above return "spike", if the range setting were at the 4000 yard distance, the target is exactly 3,000 yards away (when you read the lower 4,000 yard scale). If your radar range setting were on the 32,000 yard distance (the medium power setting), you would read the figure off the center line of the "spike". The target would be calculated to be 24,000 yards away.

In the below image, the A-Scope uses a "Bearing Meter" (placed on the wall, above the scope screen) to display a targets position in relationship to the sub. Like the scope views, OTC allows you to zoom-in the view to get a better view of the device.

http://i175.photobucket.com/albums/w132/crawlee/USAscopeStation.jpg


Sorry for the image clarity (I simply in-larged the previous image), this close-up view shows the "arrow" of the Target Bearing is pointing at 10 degrees. The target "spike" of the A-Scope screen is 10 degrees off the Starboard bow of the sub.

http://i175.photobucket.com/albums/w132/crawlee/389106e5-af32-47d6-9dc9-70fd39a634d7_zpsf2582dfe.jpg


The below image describes the parts to the "Bearing Meter". The "arrow" (or Radar Indicator) rotates with the radar antenna, giving a relative bearing of the target when compared to the outer dial. The subs true heading (the inner dial) rotates with the subs direction of travel as compared to true north (at the top of the outer dial).

http://i175.photobucket.com/albums/w132/crawlee/SH4Img2008-05-31_212932_703.jpg


Since you're using OTC, please read the Documentation that's included with the mod. The manual called "Using Radar" should be of assistance.

[HertogJan]

Thanks for the quick response Vino,

Yes this is OTC.

So if I understand correctly everything is in yards on the range scales.

The top scale 0-60 is for when you 've set the PPI range selector to 80.000yrds, the middle scale for 32.000yrds and 0-4000 for when you've set the range selector to 4000yrds.

Leaves me to do some math when I get a bliep on the PPI...:doh:
[Edit] looked it up and 2025.37.... = 1Nm

PS_ The middle scale doesn't have a multiplier but its placed infront just behind the 0 on the lower scale, maybe due to lack of space.


[Second Edit]:har:

Was typing this and when I saved CapnScurvy posted some other help

Thanks guys really appreciate it!!

[Third edit]

Since you're using OTC, please read the Documentation that's included with the mod. The manual called "Using Radar" should be of assistance.

Will do!!

[CapnScurvy]

As you've found out, the PPI station has different power ranges for the radar "Range Selector" switch than the A-Scope. The below image shows the OTC three power ranges of the PPI as being 8,000 yards, 32,000 yards, and 80,000 yards. The function of the range selector switch gives the same result on each radar unit......a low, medium, and high power range distance.......although the actual readable ranges are different (its the way this game set up the radar :down:).


http://i175.photobucket.com/albums/w132/crawlee/PPIScreenforforum.jpg


With the OTC PPI station, both range and target bearing can be quickly known when using the correct power range scale on the screen. The low (x000 yards), and high power range scales are displayed on the left side (the high power scale has an additional zero added; x0,000)....the medium power scale (32,000 yards, or x000) are displayed on the right scale.

If the power "Range Selector" switch were put on the PPI's 8,000 yard distance (which is the same as the 4,000 yard distance of the A-Scope....the low power setting) the below "blips" range would be found using the left hand "low" power scale (x000). The "blip" is at the 3,000 yard distance line, on a 10 degree relative bearing (use the leading edge of the sweep line to just contact the blip...follow the leading edge to the outer ring, relative bearing). Just like the previous post example of the A-Scope station, the target is found at the same range and bearing.


http://i175.photobucket.com/albums/w132/crawlee/USPPI.jpg


Once you understand the differences in range divisions for the two stations (yet learning the similarities of the power settings) you should be coming up with accurate radar information no matter which station you choose.

[HertogJan]

I'm getting one of those: Ohhhh, aaah.... uhu moments :D.

:up: Thanks again, going to swing the game in to gear tonight and see if that 'moment' is permanent.

Shouldn't be a problem testing, I've been send 30Nm NNW of Truk should get some 'blieps' at Truk on radar by the time I get there.

[HertogJan]

Leaving Midway I wanted to see if all the ships around were showing and tested my newly acquired skill.
They were and everything seemed to be working so I set sail for Truk by way of Wake Island and turned on radar.

When I got to Wake I didn't get any contact report what so ever (didn't check for myself either tho) just my luck :doh: so I continued to Truk.

1024-ed to Truk and when 40Nm from patrol area I set normal time, cautiously crept in closer on the surface but again no radar contacts...

Maybe I set radar at its lowest range so checked that and made a manual sweep while I was on station... It revealed 6 stationary vessels :o.
I kept on sneaking in and and was hoping to get some report from radar stations. I got within 10Nm on a very clear day when the watch crew shouted "Ship spotted, sir" :shifty:.

Is something wrong or doesn't the game 'see' stationary vessel like watch crews sometimes don't seen vessels at long range when you can?


My MOD soup installed in this order:

TMO 2.5
TMO 2.5 Small Patch
IJN Rad_Fix for TMO2_Betaupdate
OTC for TMO 2.5
OTC 8to5 Aspect ratio_TMO
TMO Smoke Mod
ISE Stock Env_v2
ISE New clouds+waves
ISE Realistic Coulors
TDW_ DC_Water_Disturbance v2_0_SH4

[CapnScurvy]

Your asking the crew to find targets for you is like asking them to fire the deck gun and expecting a hit every time........it won't happen.

You want a kill with the deck gun without using all your ammunition.......do it yourself.

You want to use the radar to find targets........use it yourself.

Same with sonar......use it yourself. :D

The game take's into account your crews efficiency points, among several other things, to render a percentage of success in what its tasked to do. Having a radar operator finding the same targets you'll be able to do is dependant on his skill and efficiency rating. A green crew is pretty much useless.

One thing I didn't change with the radar was the variables the crew efficiency factors have on their task of reading radar. Maybe I should have, but then you wouldn't have the fun of using the radar for yourself!

Thinking about it, if you became dependant on the crew to do all that's expected of them, the game might as well not have the Deck Gun, Sonar Station, Radar Stations available for user control. You could sit back and let the crew do its thing, while you just shout out orders. I think we would grow tired of the game very quickly.

[HertogJan]

Your asking the crew to find targets for you is like asking them to fire the deck gun and expecting a hit every time........it won't happen.

You want a kill with the deck gun without using all your ammunition.......do it yourself.

You want to use the radar to find targets........use it yourself.

Same with sonar......use it yourself. :D

The game take's into account your crews efficiency points, among several other things, to render a percentage of success in what its tasked to do. Having a radar operator finding the same targets you'll be able to do is dependant on his skill and efficiency rating. A green crew is pretty much useless.

Ahhhh, the still wet behind their ears (Dutch expression), Unexperienced youth. I'll have to do something about that :arrgh!:.

Ok, the gismo is pretty new July '42 so I'll give them a bit of slack but you'd expect the crew comming fresh from Navy bootcamp to have some understanding of how it works wouldn't you?
I mean, think of it.... crewman turns the range switch to 80.000yrds..sees a bliep on the edge of the red thingy, looks at green thingy sees a spike (or two) but thinks... Noway I'm gonna tell the Captain I saw something weird on the new gismo... Who'd believe me? :88)

As a for this Capt... Brand new command, new gismo's... you can't expect Him to grasp the workings of it after just getting back from a 3 month patrol now can you? :smug:.
(had to put this in otherwise I'd get hammered).

:hmmm:... Maybe switching 2/3 of my crew wasn't that good of a idea after all..
(I tossed all but 7 officers and 7 petty officers to be able to do the crew management myself, hate getting the "to many (petty) officers" message).


One thing I didn't change with the radar was the variables the crew efficiency factors have on their task of reading radar. Maybe I should have, but then you wouldn't have the fun of using the radar for yourself!.

I'd still use it, like I still use sonar, hydrophones, AA-gun and deckgun, use rudders, set the speed, ID the traget myself, enter target solutions, set giro angle and depth, switch depth.... Ohhhh wait... I Do everything myself. :rotfl2:
But I get your point

Thinking about it, if you became dependant on the crew to do all that's expected of them, the game might as well not have the Deck Gun, Sonar Station, Radar Stations available for user control. You could sit back and let the crew do its thing, while you just shout out orders. I think we would grow tired of the game very quickly.

True, I'd be sitting behind a radio giving orders from home :rock:... Errrrr, doing that already also. :woot: