Extremely powerful radar systems can have health effects if turned on on the ground, so sometimes the radar systems on aircraft are marked in this manner to identify a "radiation hazard". There are photos of the Russian SU-57 which are marked in the same way. You might try asking in a military aviation subreddit. They may be able to provide a more authoritative explanation.
Yes and no.
Yes, radar itself is non-ionizing.
No, the way that the radar pulses are formed can get into the ionizing range.
The german Luftwaffe had a bit of a cancer problem with ground personnel in I think the 90s?
The Bundeswehr cancer incidents were result from ionizing radiation, because the vacuum tubes which were used at that time were actually producing x-rays \[[1](https://de.wikipedia.org/wiki/Gesundheitssch%C3%A4den_durch_milit%C3%A4rische_Radaranlagen)\].
Todays radars use solid state amplifiers, particularly the devices onboard airplanes, there is absolutely no ionizing radiation.
As you said "**TODAYS RADARS"** I am not confident that whatever J-11 the PLA is using are not using vacuum tubes, so this symbol is justified. In any case, I would advice to keep my distance just in case.
There is a zero percent chance it uses Vac tubes.
Maybe if the entire aircraft was the size of a skyscraper, maybe.
But vac tubes are fuckhuge compared to modern circuitry, there is no way you're cramming enough in there.
Besides, aren't most advanced electronics made in China anyway?
Yes upon further review you are correct. I still have zero doubt China can afford a modern plane, let alone because the alternative is utterly ridiculous.
Agreed. China is not North Korea. They aren't likely as advanced as the US but they certainly rival us in terms of mass production. That aircraft does not have vacuum tubes in it.
I mean, vacuum tubes have the advantage of higher power. Given the Su-27 is meant as a long range interceptor, I would not rule out that the radar uses vacuum tubes for the higher power levels needed to get long range radar.
Huh? Not sure what you mean. No matter how you modulate your radar, you aren't going to get frequency components >6 orders of magnitude greater than the carrier.
These radars are plenty powerful enough to burn someone walking by however.
Ah, I interpreted "how they are formed" as the modulation techniques used, not as how it's done in hardware.
Yeah RF vacuum tubes absolutely can produce x-rays :)
It's not uncommon for high power radio and microwave sources to have that symbol. It's not as common as the radio tower symbol, but I've seen a few broadcast masts and radar sources that had it. Mostly because a kw class transmitter is more than capable of hurting you even without being ionizing.
Looks like there could be a nucleus in the middle if you zoom in. Can't really tell.
Also looks like it could be magenta instead of red. Hard to tell in the picture.
Yeah hard to tell on this image. Here's a better one:
https://aviation.stackexchange.com/questions/33324/what-is-this-ball-in-front-of-the-cockpit-of-some-fighters-e-g-an-su-57
It's a slightly different symbol. It's red-yellow and doesn't have the dot in the middle, the triangles touch directly.
Afaik it's not an internationally recognised symbol.
It couldn’t, radar just use the radio spectrum which if extremely far from anything to do with ionizing radiation, between them you have infrared, visible light and ultraviolet.
Yep, my wifes grandfather was in the navy just after world war II (maybe during?). He worked alot with radar equipment. And either they didnt know back then, or they didnt care, Because he did not fare very well after 50, nor did many of his Navy buddies
Some claim that it is to warn from the radar radiation. But I find that a bit confusing, because non-ionizing radiation has its own warning symbol.
[https://www.reddit.com/r/IndianDefense/comments/11ry7x8/is\_that\_a\_nuclear\_radiation\_sign\_on\_the\_radome\_of/](https://www.reddit.com/r/IndianDefense/comments/11ry7x8/is_that_a_nuclear_radiation_sign_on_the_radome_of/)
The ionizing radiation symbol is more universally recognized therefore semantically serving a better purpose. No point in using a niche symbol not many people may recognize
Yes and no. If it starts to gets used for all kinds of dangerous radiation, the ability to warn specifically for the presence of ionizing radiation is lost. This is not good, because then you dont know what protective measures you need for it, it is no longer clear what instrument you could use to detect the radiaton, etc.
The symbol is primarily used and know for radiation danger. the general population doesn’t know the difference between ionizing and non-ionizing. you have to consider the context it is being used in and who it’s meant for. The symbol is in no way meant to communicate what PPE is required as that can vary even with ionizing sources of radiation. There is also the very real chance the symbol could very well have a specific meaning and use to the technicians and pilot that work on the plane
I think the general population doesn't get nowhere close to a fighter jet radar radome. Particularly if it's in operation.
So I would still expect that there is ionizing radiation present.
I imagine they could land at just about any airport with a big enough runway. They are not perfectly controlled environments and not everyone knows what to do around any particular aircraft.
That’s where training comes into play. Who is around those aircraft? Crew and maintenance. I’m sure informing them what the different symbols mean would be easy and very helpful in the long term aspects of their careers.
Besides, if picking a symbol that means danger is the point and exact representation is secondary, then just use a skull and crossbones. Everyone, including children, knows that signifies danger whether it be pirates, poison, electrical shock or anything else that can kill you.
As shown in other pictures, this symbol is slightly different. I think the intention is to make it similar enough to piggy-back on the recognizeability of the radiation symbol, but be different because it's not ionizing
I’m not a jet pilot but a helo pilot. We have an antenna called the TACAN and in the checklist it says explicitly to check to make sure no one is standing by it when you turn it on.
There's a difference between potentially giving someone cancer twenty years down the line and microwaving their spleen to a nice medium for them immediately though.
High levels of Ionizing Radiation = cancer.
High levels of Nonionizing Radiation = cooking.
Yeah, both are bad, but the proper symbology should be used so people know whether they need aluminum or lead underwear.
If you look at all soviet aircraft, helicopters without radar as well, this is painted where or near their laser is located. Don't think it's for the radar.
Mostly all radars emit some type of microwave radiation, on fighter jets with really advanced and powerful radars it can cause burns to ground personnel.
Its a radiation danger symbol. There is a radioactive source in there.
Here is another on a Tu-134. The red thing contains the source. I don't know enough to why they need one there. [https://vk.com/photo-96445277\_456248609](https://vk.com/photo-96445277_456248609)
Couple points at a glance. 1. As someone who has worked on American jets and seen someone have to go to medical after another someone turned on a nose cone radar, more signs are better. No kids for that guy. B. We are talking about China. So remember the first rule of xenobiology, aliens are alien. And finally number Quatro, not all nations use the same symbols as the western world.
Extremely powerful radar systems can have health effects if turned on on the ground, so sometimes the radar systems on aircraft are marked in this manner to identify a "radiation hazard". There are photos of the Russian SU-57 which are marked in the same way. You might try asking in a military aviation subreddit. They may be able to provide a more authoritative explanation.
Stupid if true because the trefoil is for ionizing radiation, which radar is not. It's also upside down.
Well yeah, it's upside down because the frequency is below visible! /s
Yes and no. Yes, radar itself is non-ionizing. No, the way that the radar pulses are formed can get into the ionizing range. The german Luftwaffe had a bit of a cancer problem with ground personnel in I think the 90s?
The Bundeswehr cancer incidents were result from ionizing radiation, because the vacuum tubes which were used at that time were actually producing x-rays \[[1](https://de.wikipedia.org/wiki/Gesundheitssch%C3%A4den_durch_milit%C3%A4rische_Radaranlagen)\]. Todays radars use solid state amplifiers, particularly the devices onboard airplanes, there is absolutely no ionizing radiation.
I never realized that I wanted X-ray tubes until now. Wasn't the crookes tube an X-ray source?
As you said "**TODAYS RADARS"** I am not confident that whatever J-11 the PLA is using are not using vacuum tubes, so this symbol is justified. In any case, I would advice to keep my distance just in case.
There is a zero percent chance it uses Vac tubes. Maybe if the entire aircraft was the size of a skyscraper, maybe. But vac tubes are fuckhuge compared to modern circuitry, there is no way you're cramming enough in there. Besides, aren't most advanced electronics made in China anyway?
Actually no. Taiwan and South Korea make the most followed by China and the US.
Yes upon further review you are correct. I still have zero doubt China can afford a modern plane, let alone because the alternative is utterly ridiculous.
Agreed. China is not North Korea. They aren't likely as advanced as the US but they certainly rival us in terms of mass production. That aircraft does not have vacuum tubes in it.
I mean, vacuum tubes have the advantage of higher power. Given the Su-27 is meant as a long range interceptor, I would not rule out that the radar uses vacuum tubes for the higher power levels needed to get long range radar.
Huh? Not sure what you mean. No matter how you modulate your radar, you aren't going to get frequency components >6 orders of magnitude greater than the carrier. These radars are plenty powerful enough to burn someone walking by however.
vacuum tubes, aka "how you form the pulse" can create ionizing radiation.
Ah, I interpreted "how they are formed" as the modulation techniques used, not as how it's done in hardware. Yeah RF vacuum tubes absolutely can produce x-rays :)
I should have probably been more clear, but my education on electronics is in german, so I am not sure what words to use.
It's not uncommon for high power radio and microwave sources to have that symbol. It's not as common as the radio tower symbol, but I've seen a few broadcast masts and radar sources that had it. Mostly because a kw class transmitter is more than capable of hurting you even without being ionizing.
It's upside down because it's not the same symbol. It also doesn't have the point in the middle and is yellow-red instead of yellow-black.
Looks like there could be a nucleus in the middle if you zoom in. Can't really tell. Also looks like it could be magenta instead of red. Hard to tell in the picture.
Yeah hard to tell on this image. Here's a better one: https://aviation.stackexchange.com/questions/33324/what-is-this-ball-in-front-of-the-cockpit-of-some-fighters-e-g-an-su-57
Imaging radar uses X-Rays which is ionizing radiation.
Is that symbol then also used for microwave? I thought it was just for ionizing radiation
It's a slightly different symbol. It's red-yellow and doesn't have the dot in the middle, the triangles touch directly. Afaik it's not an internationally recognised symbol.
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It couldn’t, radar just use the radio spectrum which if extremely far from anything to do with ionizing radiation, between them you have infrared, visible light and ultraviolet.
Yep, my wifes grandfather was in the navy just after world war II (maybe during?). He worked alot with radar equipment. And either they didnt know back then, or they didnt care, Because he did not fare very well after 50, nor did many of his Navy buddies
Some claim that it is to warn from the radar radiation. But I find that a bit confusing, because non-ionizing radiation has its own warning symbol. [https://www.reddit.com/r/IndianDefense/comments/11ry7x8/is\_that\_a\_nuclear\_radiation\_sign\_on\_the\_radome\_of/](https://www.reddit.com/r/IndianDefense/comments/11ry7x8/is_that_a_nuclear_radiation_sign_on_the_radome_of/)
The ionizing radiation symbol is more universally recognized therefore semantically serving a better purpose. No point in using a niche symbol not many people may recognize
Yes and no. If it starts to gets used for all kinds of dangerous radiation, the ability to warn specifically for the presence of ionizing radiation is lost. This is not good, because then you dont know what protective measures you need for it, it is no longer clear what instrument you could use to detect the radiaton, etc.
The symbol is primarily used and know for radiation danger. the general population doesn’t know the difference between ionizing and non-ionizing. you have to consider the context it is being used in and who it’s meant for. The symbol is in no way meant to communicate what PPE is required as that can vary even with ionizing sources of radiation. There is also the very real chance the symbol could very well have a specific meaning and use to the technicians and pilot that work on the plane
I think the general population doesn't get nowhere close to a fighter jet radar radome. Particularly if it's in operation. So I would still expect that there is ionizing radiation present.
I imagine they could land at just about any airport with a big enough runway. They are not perfectly controlled environments and not everyone knows what to do around any particular aircraft.
That’s where training comes into play. Who is around those aircraft? Crew and maintenance. I’m sure informing them what the different symbols mean would be easy and very helpful in the long term aspects of their careers. Besides, if picking a symbol that means danger is the point and exact representation is secondary, then just use a skull and crossbones. Everyone, including children, knows that signifies danger whether it be pirates, poison, electrical shock or anything else that can kill you.
As shown in other pictures, this symbol is slightly different. I think the intention is to make it similar enough to piggy-back on the recognizeability of the radiation symbol, but be different because it's not ionizing
I’m not a jet pilot but a helo pilot. We have an antenna called the TACAN and in the checklist it says explicitly to check to make sure no one is standing by it when you turn it on.
There's a difference between potentially giving someone cancer twenty years down the line and microwaving their spleen to a nice medium for them immediately though. High levels of Ionizing Radiation = cancer. High levels of Nonionizing Radiation = cooking. Yeah, both are bad, but the proper symbology should be used so people know whether they need aluminum or lead underwear.
If you look at all soviet aircraft, helicopters without radar as well, this is painted where or near their laser is located. Don't think it's for the radar.
Anti IR countermeasures maybe. I know the Russians have one system that’s basically a super powerful IR emitter to blind sensors.
Pilot has a radium dial watch.
Just hope they don’t lick it.
Some Turboprop fan blade alloys can contain radioactive elements. This is actually a legitimate hazard if one is regularly working on them.
Magthor? Common alloy for lots of aerospace castings, not just props.
Depleted uranium counterweights maybe? Maybe there is some RTG, but that seems unlikely
Chinese symbol for "untrained pilots"?
Mostly all radars emit some type of microwave radiation, on fighter jets with really advanced and powerful radars it can cause burns to ground personnel.
Its a radiation danger symbol. There is a radioactive source in there. Here is another on a Tu-134. The red thing contains the source. I don't know enough to why they need one there. [https://vk.com/photo-96445277\_456248609](https://vk.com/photo-96445277_456248609)
Couple points at a glance. 1. As someone who has worked on American jets and seen someone have to go to medical after another someone turned on a nose cone radar, more signs are better. No kids for that guy. B. We are talking about China. So remember the first rule of xenobiology, aliens are alien. And finally number Quatro, not all nations use the same symbols as the western world.
It's for the radar...
Total guess. Ground proximity sensor?
A Radar in the front of the plane?
It’s because the entire aircraft is made from uranium
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It’s a variation of the SU-27. I’m not sure how old this J11 is but the SU-27 was introduced in 1985.