Page 2 of 2
RE: Radar DETECTORS
Posted: Mon Jul 15, 2019 10:56 pm
by spence
The Japanese had RADAR that displayed "A" and "B" scans. It would give you a bearing but generally not a good range.
Modern surface search radar gives a really good ranges but the bearing is not so good. We would routinely take several ranges off prominent points and structures on land and fix our position thereby. Three ranges would give a very tiny triangle for their intersections but 3 bearings would result in a much larger triangle due to estimation of the bearings.
The older style fire control radars required one to point the radar directly at the target to get a decent return signal (we had a Mk 52 FC on my first ship in 1973 which so old the USN had no parts).
RE: Radar DETECTORS
Posted: Mon Jul 15, 2019 11:04 pm
by spence
Allied radar advanced very quickly, though, and by the Battle of Surigao Strait radar fire control was lethal.
It took a while to train operators to use radar FC but the CO of USS Washington trained his gunners hard and the results were plain in the damage to the HIJMS Kirishima in NOV 1942.
www.navweaps.com/index_lundgren/Kirishi ... alysis.pdf
RE: Radar DETECTORS
Posted: Tue Jul 16, 2019 6:11 pm
by AW1Steve
ORIGINAL: spence
The Japanese had RADAR that displayed "A" and "B" scans. It would give you a bearing but generally not a good range.
Modern surface search radar gives a really good ranges but the bearing is not so good. We would routinely take several ranges off prominent points and structures on land and fix our position thereby. Three ranges would give a very tiny triangle for their intersections but 3 bearings would result in a much larger triangle due to estimation of the bearings.
The older style fire control radars required one to point the radar directly at the target to get a decent return signal (we had a Mk 52 FC on my first ship in 1973 which so old the USN had no parts).
I'll have to disagree somewhat on that point. From 1977 (using a 1960 vintage RADAR) to the 1980's (using a 1970's RADAR) till the mid 1990's (using an then experimental, now standard RADAR) I was able to make successful RADAR "run-in's" on periscopes from up to 40NM's based upon a single "hit". [:)]
RE: Radar DETECTORS
Posted: Tue Jul 16, 2019 11:36 pm
by Rusty1961
ORIGINAL: jdsrae
Research then led to the radar detector detector
Now how does that work given the majority of detectors are passive and only receive?
RE: Radar DETECTORS
Posted: Wed Jul 17, 2019 1:04 am
by USSAmerica
ORIGINAL: Rusty1961
ORIGINAL: jdsrae
Research then led to the radar detector detector
Now how does that work given the majority of detectors are passive and only receive?
Ooh, ooh! I know the answer to that one. I guess working on ECM gear during my time in the Navy was good for something. [:D]
RE: Radar DETECTORS
Posted: Wed Jul 17, 2019 8:39 am
by tarkalak
ORIGINAL: USSAmerica
ORIGINAL: Rusty1961
ORIGINAL: jdsrae
Research then led to the radar detector detector
Now how does that work given the majority of detectors are passive and only receive?
Ooh, ooh! I know the answer to that one. I guess working on ECM gear during my time in the Navy was good for something. [:D]
Most targets are passive as well but radars still detect them. Hmmm. [&:]
I would use the power of wild guessing and say that the radar detector reflects some of the radar emissions in a detectable way.
RE: Radar DETECTORS
Posted: Wed Jul 17, 2019 10:57 am
by Korvar
Tarkalak,
You can find
the answer here.
RE: Radar DETECTORS
Posted: Wed Jul 17, 2019 10:59 am
by Rusty1961
ORIGINAL: tarkalak
ORIGINAL: USSAmerica
ORIGINAL: Rusty1961
Now how does that work given the majority of detectors are passive and only receive?
Ooh, ooh! I know the answer to that one. I guess working on ECM gear during my time in the Navy was good for something. [:D]
Most targets are passive as well but radars still detect them. Hmmm. [&:]
I would use the power of wild guessing and say that the radar detector reflects some of the radar emissions in a detectable way.
Care to elaborate on your hypothesis. This is very interesting.
RE: Radar DETECTORS
Posted: Wed Jul 17, 2019 11:05 am
by tarkalak
RE: Radar DETECTORS
Posted: Wed Jul 17, 2019 11:12 am
by tarkalak
ORIGINAL: Rusty1961
ORIGINAL: tarkalak
ORIGINAL: USSAmerica
Ooh, ooh! I know the answer to that one. I guess working on ECM gear during my time in the Navy was good for something. [:D]
Most targets are passive as well but radars still detect them. Hmmm. [&:]
I would use the power of wild guessing and say that the radar detector reflects some of the radar emissions in a detectable way.
Care to elaborate on your hypothesis. This is very interesting.
I come from the axiom that the Radar detector is detected.
If the target is passive and does not emit, it has to reflect or distort to be detected.
This is how astronomers detect dark matter as far as I know. Other then that I am not knowledgeble enough in the field to know.
EDIT: In retrospect my answer is not useful in practice.
If you can detect the radar detector's echo you can probably detect the much bigger vehicle it is attached to. Unless you want to specifically detect the presense of the radar detector itself, as is the case with the link in the above post.
RE: Radar DETECTORS
Posted: Wed Jul 17, 2019 11:49 am
by Korvar
Apparently radar detectors have an oscillator which radiates, which means they are not an entirely passive sensor; the 'active' component is simply a leaking bi-product of signal conversion. Although it would probably be precluded from commercial products, I would guess a lead shell would mitigate this? As long as the receiving antenna(s) are outside, the internal circuitry "should" be able to be shielded without issue. Commercial radar detectors can get around their detection (without using lead) by having a second detector which listens for 'detector detector' emissions, and it shuts down the primary oscillator when detected.
Electronic Warfare quickly becomes a quagmire of a countermeasure race. I think it ultimately boils down to which 'side' has the most knowledge of the other's EW capabilities, who can build the most sensitive equipment, and who is willing to spend the most to achieve the last countermeasure layer.
I don't claim any EW expertise either, and I think the problem with obtaining a thorough answer will be related to my 1st reply - those who DO know won't be able to tell us. [:D]
RE: Radar DETECTORS
Posted: Wed Jul 17, 2019 11:55 am
by Korvar
Some more information regarding the Superheterodyne Receiver technology which is the basis for commercial radar detection:
RE: Radar DETECTORS
Posted: Wed Jul 17, 2019 6:05 pm
by Rusty1961
ORIGINAL: Korvar
Apparently radar detectors have an oscillator which radiates, which means they are not an entirely passive sensor; the 'active' component is simply a leaking bi-product of signal conversion. Although it would probably be precluded from commercial products, I would guess a lead shell would mitigate this? As long as the receiving antenna(s) are outside, the internal circuitry "should" be able to be shielded without issue. Commercial radar detectors can get around their detection (without using lead) by having a second detector which listens for 'detector detector' emissions, and it shuts down the primary oscillator when detected.
Electronic Warfare quickly becomes a quagmire of a countermeasure race. I think it ultimately boils down to which 'side' has the most knowledge of the other's EW capabilities, who can build the most sensitive equipment, and who is willing to spend the most to achieve the last countermeasure layer.
I don't claim any EW expertise either, and I think the problem with obtaining a thorough answer will be related to my 1st reply - those who DO know won't be able to tell us. [:D]
The amount of leakage is miniscule compared to that of the radar which the detector is designed to detect. It's about power and the inverse square of the intensity.
If a radar has a 35,000 yard range, say that we're dealing with a radar in with these WW2 DDs in the game, the detectors can detect said radar almost 3x as far. There is no way the radar unit would detect said leakage unless the detector was very close. leakage in circuitry is very weak.
RE: Radar DETECTORS
Posted: Wed Jul 17, 2019 6:17 pm
by Korvar
Yes, oscillation emissions are typically discussed in the context of a civilian, commercial application (i.e. highway vehicle usage) where distances are much shorter. In any case, I'm not aware of any detection countermeasures besides jamming which date back to WW2.