LWAMI and FFG sonar displays broken?

Fishbreath · 11-15-14, 05:33 PM

With LWAMI 3.11 and DW 1.04 on Steam, I find that I frequently am missing contact lines on my towed array waterfall—I won't even see the line for myself, although I am in the contact list with a SNR of 60. I see it fine if I disable LWAMI.

Something similar happens with sonobuoy displays—if I see myself at a distance because of a high-speed run, when I slow down below a certain threshold I instantly drop off the display, without any tailing off.

Something possibly related happens with active sonar. For poor contacts, I'll hear the echo sound effect, but won't see anything on the display. Only solid contacts show up. It seems like, when I install LWAMI, I'm missing graphics for faint contacts.

Anyone else had something similar, or have any ideas for a solution? I'm too used to having AI helos with dipping sonar to be altogether happy playing without LWAMI.

Molon Labe · 11-15-14, 09:39 PM

I'm not 100% sure because this was a change made before I was on the mod team, but I think LW turned down the sensitivity of the broadband on the TA while boosting it for the spherical/cylindrical arrays, so that is probably the most salient factor. Also it's just possible that the changes in base signal, sound-speed relationship, and sensor sensitivity just mean the contact is fainter.

With the FFG active sonar, I don't believe there is such a thing as a faint active contact in stock DW. It literally detects anything within 10 nm not in the baffles (although not necessarily cross-layer--man, it's been too long, I should know this for sure). With LWAMI, it's rare to ever get a contact as strong as you'll get in stock DW because it's set up so that aspect and target size make a huge difference. But, it's all the same audio whether the contact is weak or strong.

Fishbreath · 11-16-14, 12:08 AM

Thanks for the explanation on the active sonar. A lot of the instances of weak contacts I came across were Kilos, probably bow- or stern-on.

For the FFG's towed array, though I don't think it's a sensitivity tweak as much as a display problem. I did some testing, running at ten knots and streaming the towed array, and looking at the ownship contact.

The LWAMI version took longer to pull the contact out of the noise while coming out of the noisy zone behind the frigate, but otherwise, they performed nearly the same. Both stock and LWAMI show a contact with signal to noise ratio in the 60-70 range, but LWAMI wasn't showing it on the waterfall for me.

Edit: here are some screenshots to illustrate what looks like a problem case to me. I'm wondering if there's just something wrong with my installation, maybe? I'll try reinstalling stuff.

Fishbreath · 11-17-14, 12:37 AM

Reinstalling stuff doesn't seem to have done anything. I'll have a poke around the databases, maybe, and see if I can see if there's anything in particular up.

Fishbreath · 11-17-14, 11:08 AM

The only differences in the database for the towed array sensor seem to be the detection curve (which I assume means sensitivity?) and Nrd, which changed from -10 in the stock database to 0 in the LWAMI database. (Every other passive sonar in the first page of sensors also has a negative Nrd.) I set it back to -10, and I now have a TA waterfall contact for ownship again.

What does Nrd mean?

Fishbreath · 11-17-14, 04:13 PM

It seems to be a general sensitivity parameter. 0, instead of a more sensitive -<something>, seems off to me for the ship's primary ASW sensor, especially when 0 means that the towed array can't detect its own frigate at 1500 feet away before washing out. In acoustically perfect conditions, -10 yields a poor contact on a 15kt 688i at 14,000 yards and a faint contact on the FFG from one to four knots (strong above that). I don't know what expected ranges ought to be, though.

Assuming Nrd is sensitivity and smaller/more negative numbers are better, are passive sonobuoys really as poor as they're modeled, a good deal worse than any other passive sonar system out there?

jaop99 · 11-18-14, 12:55 PM

I don't know if it is is more real the LWAMI mod, but it's more difficult in every aspect, for example, in the SubGuru's campaign "Red Storm Rising", the mission to make the russian sub surface while you play in the FFG, with LWAMI I lost several times the russian diesel sub contact even with a lot of sonobuoys deployed from the FFG and two helos at the same time!, but I have no problem detecting the diesel sub without LWAMI and with the RA 1.38 mod.

Regards!

11-15-14, 05:33 PM	#1
Fishbreath Watch Join Date: Jan 2010 Posts: 22 Downloads: 14 Uploads: 0	LWAMI and FFG sonar displays broken? With LWAMI 3.11 and DW 1.04 on Steam, I find that I frequently am missing contact lines on my towed array waterfall—I won't even see the line for myself, although I am in the contact list with a SNR of 60. I see it fine if I disable LWAMI. Something similar happens with sonobuoy displays—if I see myself at a distance because of a high-speed run, when I slow down below a certain threshold I instantly drop off the display, without any tailing off. Something possibly related happens with active sonar. For poor contacts, I'll hear the echo sound effect, but won't see anything on the display. Only solid contacts show up. It seems like, when I install LWAMI, I'm missing graphics for faint contacts. Anyone else had something similar, or have any ideas for a solution? I'm too used to having AI helos with dipping sonar to be altogether happy playing without LWAMI.

11-15-14, 09:39 PM	#2
Molon Labe Silent Hunter Join Date: Jun 2004 Location: Along the Watchtower Posts: 3,810 Downloads: 27 Uploads: 5	I'm not 100% sure because this was a change made before I was on the mod team, but I think LW turned down the sensitivity of the broadband on the TA while boosting it for the spherical/cylindrical arrays, so that is probably the most salient factor. Also it's just possible that the changes in base signal, sound-speed relationship, and sensor sensitivity just mean the contact is fainter. With the FFG active sonar, I don't believe there is such a thing as a faint active contact in stock DW. It literally detects anything within 10 nm not in the baffles (although not necessarily cross-layer--man, it's been too long, I should know this for sure). With LWAMI, it's rare to ever get a contact as strong as you'll get in stock DW because it's set up so that aspect and target size make a huge difference. But, it's all the same audio whether the contact is weak or strong. __________________

11-18-14, 12:55 PM	#7
jaop99 Loader Join Date: Feb 2014 Location: Cancun, Mexico Posts: 89 Downloads: 26 Uploads: 0	LWAMI 3.11 I don't know if it is is more real the LWAMI mod, but it's more difficult in every aspect, for example, in the SubGuru's campaign "Red Storm Rising", the mission to make the russian sub surface while you play in the FFG, with LWAMI I lost several times the russian diesel sub contact even with a lot of sonobuoys deployed from the FFG and two helos at the same time!, but I have no problem detecting the diesel sub without LWAMI and with the RA 1.38 mod. Regards!

11-16-14, 12:08 AM	#3
Fishbreath Watch Join Date: Jan 2010 Posts: 22 Downloads: 14 Uploads: 0	Thanks for the explanation on the active sonar. A lot of the instances of weak contacts I came across were Kilos, probably bow- or stern-on. For the FFG's towed array, though I don't think it's a sensitivity tweak as much as a display problem. I did some testing, running at ten knots and streaming the towed array, and looking at the ownship contact. The LWAMI version took longer to pull the contact out of the noise while coming out of the noisy zone behind the frigate, but otherwise, they performed nearly the same. Both stock and LWAMI show a contact with signal to noise ratio in the 60-70 range, but LWAMI wasn't showing it on the waterfall for me. Edit: here are some screenshots to illustrate what looks like a problem case to me. I'm wondering if there's just something wrong with my installation, maybe? I'll try reinstalling stuff.

11-17-14, 12:37 AM	#4
Fishbreath Watch Join Date: Jan 2010 Posts: 22 Downloads: 14 Uploads: 0	Reinstalling stuff doesn't seem to have done anything. I'll have a poke around the databases, maybe, and see if I can see if there's anything in particular up.

11-17-14, 11:08 AM	#5
Fishbreath Watch Join Date: Jan 2010 Posts: 22 Downloads: 14 Uploads: 0	The only differences in the database for the towed array sensor seem to be the detection curve (which I assume means sensitivity?) and Nrd, which changed from -10 in the stock database to 0 in the LWAMI database. (Every other passive sonar in the first page of sensors also has a negative Nrd.) I set it back to -10, and I now have a TA waterfall contact for ownship again. What does Nrd mean?

11-17-14, 04:13 PM	#6
Fishbreath Watch Join Date: Jan 2010 Posts: 22 Downloads: 14 Uploads: 0	It seems to be a general sensitivity parameter. 0, instead of a more sensitive -<something>, seems off to me for the ship's primary ASW sensor, especially when 0 means that the towed array can't detect its own frigate at 1500 feet away before washing out. In acoustically perfect conditions, -10 yields a poor contact on a 15kt 688i at 14,000 yards and a faint contact on the FFG from one to four knots (strong above that). I don't know what expected ranges ought to be, though. Assuming Nrd is sensitivity and smaller/more negative numbers are better, are passive sonobuoys really as poor as they're modeled, a good deal worse than any other passive sonar system out there?