Radar warning

rtr82 · 11-17-15, 04:23 PM

Hi,

How should I adjust Metox radar warning sensor so that it only detects aircraft radar, not radar used by destroyers .

I already tried adjusting the MinHeight value, but then rw did not work at all.

Thanks!

Aktungbby · 11-17-15, 06:10 PM

rtr82!

I'm confused by the question; the metox could only detect Air-to-surface radar from Allied aircraft...aircraft for use as the MkII "1½-metre ASV

Quote:

the British fitted the RAF Mk II AI (Airborne Interception) radar into Coastal Command aircraft for use as the MkII "1½-metre ASV". The radar's known AI weaknesses — problems due to land clutter and inability to determine height effectively, which caused its failure in night fighters — were no handicap in this new role. With two range scales, 0–9 and 0–36 miles, it could detect surfaced U-boats at up to 12 miles (19 km) and land at up to 70 miles, though a typical U-boat detection range was 5 miles. The radar had a fairly crude display by today's standards, but was able to give the range and an approximate direction within an arc either side of the aircraft heading. Returns were lost in sea clutter once the aircraft was within about 1 mile of the U-boat, but usually by then, the aircraft was within visual range —- and the U-boat was well into a crash dive.The Metox sets received the transmitted pulses from the ASV and rendered them as audible beeps. It enjoyed the usual advantage of radar detectors over radar in that the signal is direct and only had to travel one way whereas the radar has to detect the very weak reflection from the submarine. Most radars increase the number of pulses and decrease the width of the pulses when switched to a shorter range, the shorter pulse widths allow the radar to look at closer objects. The Metox exploited the fact that once the radar operator changed the range indication from 36 miles (58 km) to 9 miles (14 km), the pulse repetition frequency of the radar's transmitter doubled. Radar cannot detect any reflections returned earlier than half a pulse width so when the U-boat was closer than 9 miles (14 km) the operator would change to the shorter scale. If the Metox set started beeping at twice the rate, the U-boat knew that they had been detected. By the time the aircraft was close enough to the U-boat's position to energise the Leigh light, the U-boat was well under the water. As a bonus, the Metox set would also provide warning in excess of visual range in daylight.

Required reading:http://uboat.net/technical/detectors.htm

rtr82 · 11-17-15, 06:35 PM

Hi, Aktungbby

Yes, Metox could only detect air-to-surface radar, but in SH3 it detects both, aircraft and destroyer radar.

So is there way to adjust that sensor so that it does not detect destroyer radar, only aircraft?

HW3 · 11-17-15, 10:06 PM

rtr82 is right, it does detect both.

Jimbuna · 11-18-15, 08:02 AM

Quote:

Originally Posted by HW3

rtr82 is right, it does detect both.

Rgr that.

Quote:

Originally Posted by rtr82

Yes, Metox could only detect air-to-surface radar, but in SH3 it detects both, aircraft and destroyer radar.

So is there way to adjust that sensor so that it does not detect destroyer radar, only aircraft?

I'm not aware of any current fix.

HanSolo78 · 11-18-15, 08:54 AM

In the sensors.dat file there should be values for metox radar. Have a look at the min height values. They should be higher than stock.

rtr82 · 11-20-15, 05:08 PM

Quote:

Originally Posted by HanSolo78

In the sensors.dat file there should be values for metox radar. Have a look at the min height values. They should be higher than stock.

I tried that, if I set MinHeight value above 4 meters rwr just stops working completely.

Fahnenbohn · 11-21-15, 06:57 AM

Why was the Metox not able to detect radar signals from destroyers ?

CaptBones · 12-20-15, 01:30 PM

Because surface ship radars operate on different frequencies, have different sweep rates, different sweep heights, different pulse repetition rates, different pulse width, etc....all of which makes them very different from radars installed in aircraft. Like all detection devices, METOX could only "see" what it was looking for and its designers didn't know everything that they needed to design it to look for...

Leitender · 01-10-16, 10:15 PM

The french Metox R600 had a bandwith from 0,65m to 2,65m. Together with its first interim "biscay cross" antenna it could detect signals from 1,2m to 1,8m, no matter from where they had been emitted. E.g. not only airbased ASV MkI and MkII were within this range, but also ship based meter radar types 286 and 290/291 (1,4m, both simulated in SH3). Also the american meter radar type SC (1,36m, also included in SH3) could be detected.

The original range of Metox was 10-12km with biscay cross antenna and up to 18km with later Bali antenna (0,75m-3,00m) against planes or ships. Land based radar sets could be detected at up to 100km. The original value in SH3 (4.000m) is much to less and does not represent the effectiveness of that rwr.

An early fine-tuning was done by Stiebler in his "radar detection mod" from 2005. You may read the included description.

LGN1 · 01-11-16, 01:49 PM

Hi,

the main problem with RWRs in SH3 is that different wavelengths are not modeled, i.e., Metox also detects cm radar sets

At the time Metox entered service ships already used cm radars. It would be great to know how many ships carried cm and how many ships carried m radar sets in '42.

Regards, LGN1

Leitender · 01-13-16, 02:34 AM

Hi LGN1,

yes, this is true. In SH3, none of the RWR sets differentiate between wavelengths. Some time ago, h.sie and Stiebler tried to create a workaround for this, where the range of the Metox was reduced time by time, using the SH3 Commander´s abilities. There were some estimates about the efficiency, then puplished in h.sie´s thread.

From what we can read in different internet resources, the type 271 decimeter set was ordered 350 times and equipped at 236 ships by the sommer of 1942 (more ore less every escort ship, I assume).

But there should be many other ships equipped with meter radar at that time. We can read about many observations of meter signals from ships with the Metox apparatus. On the other hand, we can read about at least one operator which only have searched in the ASV band (around 170cm), not in the ship´s radar band (130-140cm) with his Metox, obviously because he didn´t consider the ships as a letal threat (see www.uboatarchive.net).

LGN1 · 01-13-16, 03:53 PM

Hi Leitender,

thanks for the information! Do you have some links with reports about ship detection by metox? I could never find such reports and would be very much interested.

I'm wondering why the KM never (at least to my knowledge) wanted to use RWR for shadowing ships/convoys (at least in SH3 this works great :-) ).

Best, LGN1

Leitender · 01-15-16, 02:20 AM

Hi LGN1,

in interrrogation reports of survivors or in "KTB"s (after action reports), beginning from August, 1942 at www.uboatarchive.net, you may find many notes about the "FUMB" called RWR. E.g. here:

http://www.uboatarchive.net/KTB160-3.htm

Search for "detection" (in this case, radar detection is meant. The german term is "Ortung" for radar detection). At 04.11.42 you will find

Quote:

Detection on 168 cm horizontally polarized. Dived, no attack. Detection immediately steady tone, abruptly grew louder

That was a ASV radar from an airplane. The 07.11.42, Lassen wrote:

Quote:

Patrol vessel in sight bearing 250°T (the one previously observed through the periscope). At the same moment, detection on 138 cm horizontally polarized wavering in volume. Patrol vessel put astern, tone was weaker, the Fu.M.B. antenna shows directivity, since detection is only audible when the context is transverse. In addition when the patrol vessel passes out of sight the detection is even fainter and stops altogether (low range?). Range at coming in sight of the patrol vessel about 2000-4000 meters, on passing out of sight about 6 nm.

138 cm (exactly at 136cm) is the wavelength of the american SC meter radar on ships (also represented in SH3). Later, there is a note about another radar at 258cm, eventually land based radar.

The interrogation report of the radio operator mentioned in my earlier post can be found here:

http://www.uboatarchive.net/U-517INT.htm

In Chapter IX, "GERMAN SEARCH RECEIVER" you will also find a table about some known wavelengths:

Quote:

50 cm. (about) German land-based H/A R.D.F.
80-90 cm. German surface craft R.D.F.
130-135 cm. British destroyer R.D.F.
168-172 cm. British aircraft A.S.V.
242 cm. German land-based coastal R.D.F.

Greetings

Frank

Leitender · 01-15-16, 02:33 AM

None of the german RWR could give a range, and barely a bearing (round dipole "Bali" not at all, later "Athos" round detectors were splitted into quadrants), so the commanders couldn´t use the RWR for homing purposes. It was a just a warning device.

I wonder how you manage to shadow convoys with a RWR in SH3, because information about range or bearing isn´t given by the Metox either and theres is only a written warning, no audible warning by the crew (big disadvantage!) - and this warning only comes one time. The player cannot order the radio operator to repeat or to follow the contact. Maybe you use the radar instead? With it, shadowing is possible, but even the radar was used as a warning mean. Due to the fear of beeing homed in on own radar signals, the radar was often switched off near enemy vessels or convoys.

11-17-15, 04:23 PM	#1
rtr82 Nub Join Date: Nov 2015 Posts: 3 Downloads: 1 Uploads: 0	Radar warning Hi, How should I adjust Metox radar warning sensor so that it only detects aircraft radar, not radar used by destroyers . I already tried adjusting the MinHeight value, but then rw did not work at all. Thanks!

11-17-15, 10:06 PM	#4
HW3 Navy Seal Join Date: Apr 2005 Location: Gresham Oregon Posts: 6,439 Downloads: 453 Uploads: 0	rtr82 is right, it does detect both. __________________ "Some ships are designed to sink...others require our assistance." Nathan Zelk

11-18-15, 08:54 AM	#6
HanSolo78 Sea Lord Join Date: Apr 2005 Location: Austria Posts: 1,842 Downloads: 100 Uploads: 3	In the sensors.dat file there should be values for metox radar. Have a look at the min height values. They should be higher than stock. __________________

11-17-15, 06:35 PM	#3
rtr82 Nub Join Date: Nov 2015 Posts: 3 Downloads: 1 Uploads: 0	Hi, Aktungbby Yes, Metox could only detect air-to-surface radar, but in SH3 it detects both, aircraft and destroyer radar. So is there way to adjust that sensor so that it does not detect destroyer radar, only aircraft?

11-21-15, 06:57 AM	#8
Fahnenbohn Ace of the Deep Join Date: Sep 2013 Location: France Posts: 1,072 Downloads: 155 Uploads: 0	Why was the Metox not able to detect radar signals from destroyers ?

12-20-15, 01:30 PM	#9
CaptBones The Old Man Join Date: Nov 2010 Location: Rockton, IL Posts: 274 Downloads: 208 Uploads: 0	Because surface ship radars operate on different frequencies, have different sweep rates, different sweep heights, different pulse repetition rates, different pulse width, etc....all of which makes them very different from radars installed in aircraft. Like all detection devices, METOX could only "see" what it was looking for and its designers didn't know everything that they needed to design it to look for...

01-10-16, 10:15 PM	#10
Leitender Planesman Join Date: Nov 2011 Posts: 191 Downloads: 50 Uploads: 0	The french Metox R600 had a bandwith from 0,65m to 2,65m. Together with its first interim "biscay cross" antenna it could detect signals from 1,2m to 1,8m, no matter from where they had been emitted. E.g. not only airbased ASV MkI and MkII were within this range, but also ship based meter radar types 286 and 290/291 (1,4m, both simulated in SH3). Also the american meter radar type SC (1,36m, also included in SH3) could be detected. The original range of Metox was 10-12km with biscay cross antenna and up to 18km with later Bali antenna (0,75m-3,00m) against planes or ships. Land based radar sets could be detected at up to 100km. The original value in SH3 (4.000m) is much to less and does not represent the effectiveness of that rwr. An early fine-tuning was done by Stiebler in his "radar detection mod" from 2005. You may read the included description.

01-11-16, 01:49 PM	#11
LGN1 Ace of the Deep Join Date: Mar 2006 Posts: 1,138 Downloads: 147 Uploads: 12	Hi, the main problem with RWRs in SH3 is that different wavelengths are not modeled, i.e., Metox also detects cm radar sets At the time Metox entered service ships already used cm radars. It would be great to know how many ships carried cm and how many ships carried m radar sets in '42. Regards, LGN1

01-13-16, 02:34 AM	#12
Leitender Planesman Join Date: Nov 2011 Posts: 191 Downloads: 50 Uploads: 0	Hi LGN1, yes, this is true. In SH3, none of the RWR sets differentiate between wavelengths. Some time ago, h.sie and Stiebler tried to create a workaround for this, where the range of the Metox was reduced time by time, using the SH3 Commander´s abilities. There were some estimates about the efficiency, then puplished in h.sie´s thread. From what we can read in different internet resources, the type 271 decimeter set was ordered 350 times and equipped at 236 ships by the sommer of 1942 (more ore less every escort ship, I assume). But there should be many other ships equipped with meter radar at that time. We can read about many observations of meter signals from ships with the Metox apparatus. On the other hand, we can read about at least one operator which only have searched in the ASV band (around 170cm), not in the ship´s radar band (130-140cm) with his Metox, obviously because he didn´t consider the ships as a letal threat (see www.uboatarchive.net).

01-13-16, 03:53 PM	#13
LGN1 Ace of the Deep Join Date: Mar 2006 Posts: 1,138 Downloads: 147 Uploads: 12	Hi Leitender, thanks for the information! Do you have some links with reports about ship detection by metox? I could never find such reports and would be very much interested. I'm wondering why the KM never (at least to my knowledge) wanted to use RWR for shadowing ships/convoys (at least in SH3 this works great :-) ). Best, LGN1

01-15-16, 02:33 AM	#15
Leitender Planesman Join Date: Nov 2011 Posts: 191 Downloads: 50 Uploads: 0	None of the german RWR could give a range, and barely a bearing (round dipole "Bali" not at all, later "Athos" round detectors were splitted into quadrants), so the commanders couldn´t use the RWR for homing purposes. It was a just a warning device. I wonder how you manage to shadow convoys with a RWR in SH3, because information about range or bearing isn´t given by the Metox either and theres is only a written warning, no audible warning by the crew (big disadvantage!) - and this warning only comes one time. The player cannot order the radio operator to repeat or to follow the contact. Maybe you use the radar instead? With it, shadowing is possible, but even the radar was used as a warning mean. Due to the fear of beeing homed in on own radar signals, the radar was often switched off near enemy vessels or convoys.