New Manty ship ideas.

Montrose Toast wrote:As a Retired USN IS [ret 2003], that used to teach this.
Solberg is on the money.

Active = a transmitter with a receiver working together.

Passive = just a receiver.

Semi-Active = a seperate transmitter and receiver [ship's radar lighting up the target and the missile's radar receiver homing in on that target's radar reflection.]

Note that you can use active systems to passively collect data by turning off the transmitter but, you need your target to be active ATT.

You just inspired a thought about Honorverse missile guidance. We have all been at least somewhat frustrated by Weber's handwavium regarding limited numbers of missile control links and increasing lag time for missile control links making missiles less accurate as range
increases. Perhaps Honorverse missiles have semi active guidance systems that depend on the ship lighting up the target?


Also, while radar reflection signal strength is limited by the inverse squared relationship, Honorverse ships have huge RADAR and LADAR arrays compared to wait we use (100 meters across vs 10 meters across) and no doubt enormous transmitter power averaging Gigawatts or even Terrawatts output. These two factors do increase detection range.

namelessfly wrote:You just inspired a thought about Honorverse missile guidance. We have all been at least somewhat frustrated by Weber's handwavium regarding limited numbers of missile control links and increasing lag time for missile control links making missiles less accurate as range
increases. Perhaps Honorverse missiles have semi active guidance systems that depend on the ship lighting up the target?

Any system capable of doing that at the ranges we've seen combat take place would be functionally indistinguishable from a directed energy weapon at closer ranges. A system like that would also be incredibly easy to spoof, given the capabilities of Honorverse ECM tech.

Relax wrote:

solbergb wrote:A telescope is a passive sensor. All it does is collect light. SNIP quibbles after this first main point.

A telescope is NOT a sensor at all! Let alone a passive one! A telescope is 100% separate from a sensor or emitter passive or active!

Ok fine. The eyeball is the sensor. The telescope enhances the eyeball's ability to collect visible light. Telescope+eyeball=passive sensor.

Telescope+eyeball+light source controlled by person who owns the eyeball = active sensor.

Better?

In my physics class "light" included everything from gamma-ray to radio waves. Light is photon "particles" which also behave as "waves" of various wavelenghts (which is the only thing that distinguishes an X-ray from a microwave..wavelength). The EM spectrum combines this concept with electron energy and Maxwells equations get involved, but since we were talking about telescopes, I assumed "optical telescope used by a human", not something like radio astronomy.

Optical telescopes, which I assumed we were discussing, do not work with magnetic fields (like an electron microscope) and while eyes do use electrochemical means to interpret photons most people don't consider the use of the telescope+eyeball to use anything other than light, as opposed to the EM (electromagnetic, as in dealing with movement of electrons to form electric current or magnetic fields, rather than various wavelengths of photons).

So now that we're talking about the telescope "collector" and eye "sensor", and flashlight/spotlight/etc "emitter" we can perhaps have an actual conversation from the same assumptions without the "xxx is WRONG" wording, please.

Relax wrote:NO, active sensors do NOT have higher resolution than passive. What they do have is a higher Signal to Noise ratio! More signal is coming BACK. Noise either remains the same or goes up slightly due to active emissions. Resolution remains the same. Resolution is determined by the lenses used along with the sensor! Optics 101. The data is there, but with a higher S/N ratio, you get useful information instead of "fuzz."

Resolution is not signal to noise ratio? That seems to me a distinction without a difference. More information is there to be interpreted by the brain behind the sensor, rather than being lost in the noise or having too few data points (ie, darkness) to understand what the eye+telescope is presenting.

I'm using this definition of the word (6a). Are you using (6b)?

6 a : the process or capability of making distinguishable the individual parts of an object, closely adjacent optical images, or sources of light
b : a measure of the sharpness of an image or of the fineness with which a device (as a video display, printer, or scanner) can produce or record such an image usually expressed as the total number or density of pixels in the image <a resolution of 1200 dots per inch>

In any event, I'd appreciate not being quite so pendatic over words. The words as used in the text we are discussing are less precise than either of us have used in this discussion. We're having a significant digit problem, as it were, arguing about the third or fourth digit when our data is only accurate to 1 or 2 digits.

In the Honorverse books, active sensors ALWAYS have an emitter when described in the text, passive sensors NEVER emit anything, which is rather the point.

Whether the hardware ALWAYS has emitters attached to passive sensors and just does not choose to use them when in "passive" mode is unclear, the text supports either interpretation, and military vs civilian, sollie vs manticoran vs havenite vs greyson tech might all have differences in their choices. In our world, they're sometimes combined and sometimes not.

Relax wrote:
Night flashlights for goggles have been around forever. They have improved in 2 ways though. The difference has been that night vision goggles have narrowed their spectrum emissions(rely more on IR) along with dynamic processing for blinding effect and therefore allowing one to place filters over flashlights that better block the EM spectrum that the night vision goggles use.

In my youth, training as an engineer, late-80s, the night vision sensors were pretty primitive and the automatic flash guards were slow. IR flashlights were just starting to come out but all of this stuff was strictly military, so my understanding of what could actually be done came pretty much from my friends who served in the military, Army and Marines (and not special forces or anything, just first-term-of-service grunts or in a couple cases, noncoms who'd served for less than a decade).

Lets try something else. I'm going to describe how the human body senses stuff, active and passive and Relax can tell me what the terminology he'd use for it, if it's different from mine. This should also help for anyone reading who is less technical.

I'm standing barefoot on a beach at night. If I hold perfectly still, I'm behaving like a drone with nothing but passive sensors on and under no thrust.

I can see whatever ambient light lets me see. This will probably involve little or no color resolution, but I've still got pretty good capability to sense movement.

I can hear whatever noises are in the environment, which will be made primarily by motion of other things in the environment. Leaving animals out of it, waves lapping on the beach, wind rustling through leaves etc. I can smell the salt from the sea, and some of the plant odors, carried by the breeze.

My skin measures the temperature of the air, and also wind strength, mostly by temperature gradient. If water splashes on me, that sense gets stronger (because water conducts heat better...same effect if I lick my finger and hold it up). My feet can feel the temperature and texture of the sand.

That's a lot of information to process. If I'm thinking about other things I won't notice most of this. If I still my mind I can notice more (more processing power or techs manning sensor stations). My brain still can't process all of the inputs, I have to shut my eyes to really get all the sensations from skin, nose and ears. Somebody better trained than me might have a "bigger computer" for this, and somebody who, say, hunts in this environment would interpret what I sense better (like having highly trained sensor techs).

If this information is not enough, I have many possibilities for emitters to make some senses "active". Most of these on the human body do not use the same tool as the sense. For sight, I need an actual tool (a match, flashlight, cell phone screen) to generate more photons to reflect off my environment. Anything that can see is much more likely to see me.

For sound, I can clap my hands or make noises with my mouth (yodel, whistle, shout) and listen to echoes.
Anything that can hear will be more likely to notice me.

I can also start moving, this will give me both sound information (footsteps) and touch information (texture and temperature of where I step) plus different viewpoints for all senses at the cost of making me more likely to be noticed by anything that hears, or is touching the ground and can feel the vibrations. Worse, I leave tracks and scent behind, although on the beach the tide coming in will wash that away pretty soon. (it's harder to be stealthy if moving under power, your waste heat is both a problem for pinpointing you, or detecting that you were there shortly after. The grav emissions impeller drives generate are like the vibrations of my feet in the ground, or the footsteps. Running is noisier than sneaking)

Most uses of my skin beyond passively feeling the air are intrusive. Touching anything affects it directly and leaves traces (IR, chemical). Touching water disturbs it and sends vibrations. Still, touching things has better conductivity for heat than air provides and the other receptors in my skin give a lot of new information. Touching with my tongue adds an acid that releases chemicals to add further information. Crushing things with my hands (especially plants which have volatile oils) gives more information to smell. Touching something is a lot like "lighting it up" with short range active sensors. Crushing it is like doing so at full power, which has been described as approaching an energy weapon in intensity, sufficient to damage sensitive sensors on the opposition's ship.

One thing interesting about the human body is that the emitters (voice, touch, exerting force with muscle and bone, clapping hands, shining a light, etc) are rarely connected to the collectors/sensors (ears, eyes, nose, skin, tongue). Our own bodies are set up as passive receptors with a variety of emitters, and when they're used I guess that's the "semi-active" mode mentioned a few posts up.

Now the human body is not a warship, and modern sensors may well incorporate emitters routinely (processing power is cheap compared to the human brain and its sensory input, power sources are much cheaper than they used to be, sensors are more sensitive so they don't need as much emitter power, etc etc), and just turn them off when you want to "run quiet". This might be what Relax is trying to convey. It seems to me though that tech changes over time, what's efficient to do is not always the same and we know absolutely nothing about gravitics as used in the Honorverse. For example, there doesn't seem to be any kind of gravitic radar, where a grav pulse is used to get more information about the enemy. It's all "they emit, we detect, EW, crew quality and computing power determines success of stealth".

All of the active sensors we've seen described have been lightspeed (obviously sonic or chemical based sensors are pointless in space, and space doesn't conduct free electrons like water or copper wire does, so we're pretty much limited to photons at various wavelengths and "gravitics" whatever that is). Still, we have directional gravitics used for communication. Seems like it shouldn't be impossible if you can somehow get the pulse to interact with an impeller drive field (or maybe even spider drive) and "reflect".

Relax wrote:

Montrose Toast wrote:As a Retired USN IS [ret 2003], that used to teach this.
Solberg is on the money.

Active = a transmitter with a receiver working together.

Passive = just a receiver.

Semi-Active = a seperate transmitter and receiver [ship's radar lighting up the target and the missile's radar receiver homing in on that target's radar reflection.]

Note that you can use active systems to passively collect data by turning off the transmitter but, you need your target to be active ATT.

Yup, minus the part about Solberg being right and minus your last point. With older tech, before 1980's you would be correct. Time marched on long ago.

Try again. I didn't go to Boot until 81. Retired in 2003. The definitions have not changed in the military. I've seen Spy-1 used as a passive receiver as late as 2001 when I was the Intel Officer on the USS Yorktown. I worked with OS's, CT's, EW's, ST's etc...

In your world, the definitions of active, passive, and semi-active may have changed.
They have not in the USN...

As long as the active transmitter and receiver are not too far apart, say 1 light minute with the receiver having FTL communication to report a disrupted beam. This will note approximate location. Then everyone's wedges and bubbles go up and everyone zeros in with their ships, wedges up side walls and bucklers on. Adding in additional radars of all kinds, plus opticle sensors (in all the spectrums), these beams would best be pulsed and randomly directed making it harder to avoid them. I suppose they could be laser packet emails, allowing light speed communications for free to everyone and keeping expensive fast FTL communications for more urgent messages.

Kind of like free with a plan world wide texting, only in this case star system wide with huge gaps but like statistical sampling you don't catch everything you occasionally catch something. Then you multiply the transmissions and start dropping ships in the area, or within hyper limits have you LAC's parked all over the place.

May not be perfect but then nothing ever is. But something is always better than nothing. Plus it will confuse the heck out of all the Sollie Newsies and Dispatch boats. Over time it would evolve and get better.

Lord Skimper wrote:As long as the active transmitter and receiver are not too far apart, say 1 light minute with the receiver having FTL communication to report a disrupted beam. This will note approximate location. Then everyone's wedges and bubbles go up and everyone zeros in with their ships, wedges up side walls and bucklers on. Adding in additional radars of all kinds, plus opticle sensors (in all the spectrums), these beams would best be pulsed and randomly directed making it harder to avoid them. I suppose they could be laser packet emails, allowing light speed communications for free to everyone and keeping expensive fast FTL communications for more urgent messages.

Kind of like free with a plan world wide texting, only in this case star system wide with huge gaps but like statistical sampling you don't catch everything you occasionally catch something. Then you multiply the transmissions and start dropping ships in the area, or within hyper limits have you LAC's parked all over the place.

May not be perfect but then nothing ever is. But something is always better than nothing. Plus it will confuse the heck out of all the Sollie Newsies and Dispatch boats. Over time it would evolve and get better.

Have you actually calculated how many beams you would need to actually detect a ship by interrupted beams? Do you even have any concept how large an area you would need to cover with those beams?

You mention having transmitter and receiver 1 light-minute apart. Let us suppose you want to detect ships passing through an area of 1 square light-minute. So you set up a line of transmitters on one side of the square and a row of receivers on the other side of the square. To detect every ship passing through that square, you would need to space the transmitters no more than 1 ship's width apart. Let's be generous, and space them 100 meters apart (that is much too wide). To cover 1 light-minute, you would need 180,000,000 pairs of recievers and transmitters! If you wanted to cover the entire hyper-limit with such a network, you would need to cover over 5000 square light-minutes. Even if you only tried to catch 1 out of 1000 invading ships, it requires far too many detectors.

Montrose Toast wrote:Try again. I didn't go to Boot until 81. Retired in 2003. The definitions have not changed in the military. I've seen Spy-1 used as a passive receiver as late as 2001 when I was the Intel Officer on the USS Yorktown. I worked with OS's, CT's, EW's, ST's etc...

In your world, the definitions of active, passive, and semi-active may have changed.
They have not in the USN...

To Both: S and Toastie

I never quibbled with definitions. {Active, passive, semi) These are self evident. Quit dicking around at 1st grade level boys.

You guys are for some odd reasons.

Probably, from my perspective, because you don't seem to understand how a telescope/Radar etc is implemented at a base level beyond the "block" diagram.

I am pointing out how one IMPLEMENTS said systems.

WOA, HOLD THE DAMNED BOAT SOLBERG! You just stated that IR, UV, optical, X-ray are different. They are all part of the EMS. Their only difference is their wavelength! Now how said wavelength interacts with your collection device, horrors use the word telescope, will have different efficiencies doing so. A perfect reflector for optical wavelengths is certainly not optimum for X-ray, Radar but honestly does a decent job in all actuality. Why you bring electron microscope up is a head scratcher unless you somehow think RADAR, x-ray, UV, IR is not photon based...

Same goes with Resolution. 6a vanished in 1960 unless one wants to have a superficial useless discussion. A computer always has the exact same resolution data sensor feed. Always. Weather there is any useful information in said data feed is entirely dependent on S/N. Been true since the 30's and the advent of the CRT(use them in reverse). 40-50's it was the Klystron(RADAR). Solberg what you are describing is RESOLVING POWER, not RESOLUTION. That is 6a, from whatever definition source you dug that one out of. 6a = resolving power in Physics world, not Resolution. English dictionary dweebs with no understanding of Physics, well uh, yea.

How do you think the Space shuttle or the Apollo astronauts knew where they were in space? They had a crude, very large "pixels" that noted when VERY bright stars were in their "bracket", excitable thin wires with a sensor material(semi conductor) adjacent. Light hits create a charge which excites said nearby wires. Then interpolation from a star chart allowed them to determine where they were. Really no different than a camera today. MUCH MUCH larger though. Said "cameras" were on all spy satellites in the 70's. Were held as national secrets at the time in the 60's through even much of the 80's, though it was very firmly let out of the bag in the 80's with the introduction of AESA RADAR. Today, this technology is taken for granted and is now ubiquitous in cell phones.

Resolving power is the ability to distinguish objects from the fuzz(noise). This is the application of the S/N ratio to your Resolution provided by a "pixel" sensor for the last 50 years.

Transmission electron microscopes use magnetic fields as lenses, as opposed to a lens made of glass. They're powerful enough to focus a stream of electrons fine enough to have the photons transmitted show crystal structures - up to 1 million times magnification, assuming you do the sample prep properly, which is a PITA when you're working with aluminum-alumina interfaces like I was for two years (Alumina is one of the hardest ceramics, it's only a little less hard than diamond. Aluminum is soft. The bond between them is extremely durable. Imagine grinding a bonded sample to a few microns without destroying the aluminum....bleah. The microscope was fun. Sample prep, not so much)

They don't use light...because they use electrons rather than photons, they interact with electromagnetic forces, rather than the electromagnetic spectrum and thus are amenable to being focused much finer than any light-based source (barring gravitic lenses, which we can't make in our world). The same principle is why disc drives blew away optical drives back in the early 2000s. You can do 1s and 0s down nearly to atomic levels when you use magnetic polarity to store data instead of trying to aim photons at a substrate and burn 1s and 0s into it.

So yeah, to me, because I'm familiar with both technologies, I got on a tangent because EM spectrum caused me to think of actual electromagnetic methods of storing data. By the bye, an electron microscope is a partially active sensor. You shine the electron beam on a target and either the reflection (SEM) or transmitted portion (TEM) shines on your equivalent of photographic film and shows you stuff you didn't know about really tiny things, instead of things really far away.

And yes, I don't know much about how RADAR works beyond the idea that there is a radio wave emitter and a radio wave receiver and the receiver focuses on the reflections of the radio waves. Which is pretty much exactly how a human with a flashlight works. Or a bat using echolocation with sound. Conceptually it's all the same and the low level tech details really don't matter for the purposes of this discussion.

A telescope, by contrast, emits nothing except the light it collects out the end the eye (or sensor that turns it into a screen image if using something other than visible light and a purely optical method). I don't think most people perceive the part of the telescope you look into as an "emitter" in the same sense as a flashlight. So yeah, it is a passive sensor. Like I said in the first post. Sorry, we'll have to disagree on that one.

Regarding the term Resolving Power. Sorry, not in common usage. I'm sure it is a more precise term, useful when most of your sensors can be degraded by having a crappy screen or crappy software after the data is collected and you have to troubleshoot the problem.

Look, I know a lot of precise jargon for various IT problems, and some for various materials science concepts (eg...wax is identical in structure to plastic, for most of the same reasons as radar and x-rays are composed of the same physical thing...in one case photons at different wavelengths, in the other carbon chains of different length but identical chemical properties). I don't use those terms with people who don't do that kind of work, because they look at you blankly. Most people are happy thinking of wax and hard plastic as totally different things, and for all practical purposes, for most folks it is true.

To those of us mere humans who are used to thinking of stuff in terms of black boxes that do useful things for us, if the screen shows better information, we don't give a damn whether it is higher resolution or resolving power or both that accomplished it. What we experience is that if we shine a light on something, our camera takes a better picture. I'm sorry if calling that effect the word I know (Resolution) rather than the correct technical term (Resolving Power) bothered you so much.

Nobody can know everything. What I posted holds up damn well at the black box level. I'm afraid my 2 years of physics and a laser lab focused on holographic photography 25 years ago is my only exposure to optics theory. I know reflection from refraction, and a hell of a lot about how semiconductors and conductors work, can tell you how shaking a radiation source can cause a crystal structure to resonate and how to build a lab to do that kind of work (https://en.wikipedia.org/wiki/M%C3%B6ss ... ectroscopy) from scratch out of materials mostly found in the hardware store. (That's the only serious work I did with anything involving light. The "light source" is a chunk of radioactive material. You shake it with an oscillating motor. You put your sample between the source and a proportional counter, which I also know how to build out of household materials...our lab was on a budget...hook up the proportional counter to a primitive computer and there you are. Biggest problem is damping vibration. That's where I learned to pour concrete and the virtues of simple mass on damping vibration....)

But no, I can't tell you how modern military radars work beyond assuming they have an emitter and a sensor, and postulating that not EVERY military sensor is going to have an emitter, thus some senors will be purely passive.

I'll point out, however, before we went down this rathole, that my first post that started it was in fact correct on the usage of active vs passive and what they mean in terms anybody can understand. I'm still not clear why you keep calling me an idiot and completely wrong in a variety of different ways. I'm more ignorant than you on the finer points of Radar I guess, but I'd appreciate more civil language.

So to sum up.

To 99% of humans who have encountered the word, a Telescope is an optical passive sensor used by a human. It displays far away objects on a "screen" a human can see that is about the size of a quarter without in any way emitting light that can be detected baring something like the lens reflecting accidently. The fact that you seem to think Telescope also means various forms of radio telescopes, radar, lidar, etc etc does not make the rest of us ignorant and wrong. Indeed, non-optical telescopes usually have a qualifier (eg, Radio Telescope) which still indicates a passive sensor, but specifies that it is not the optical kind most folks are familiar with. This is not a technical forum. Please don't bash people for common usage.

To I suspect the majority of us, "better resolution" means "we can discern details better". How that is done isn't important enough to require another term. Again, this is nothing to get excited about. Terms like "dweeb" don't add to the conversation.

Finally, the original discussion a that started all of this was about the terms you are no longer disputing (active, passive, semi-active). Since MT agreed with me and elaborated on it, and you responded by saying both of us were wrong, without explanation and later said of course those terms mean what we said they mean....

What the hell was that about anyway? Could have saved a couple somewhat irate responses if you'd just not posted it at all, since the end result was the same.

I must be missing something you think is very important if you keep responding with insulting postings, so if I'm pissing you off, assume it's unintentional. I'm actually honestly puzzled at this point. I mean I get that we don't seem to care how the devices work at a low level, but what does it matter if the behavior is the same to the sensor tech?

Relax wrote:How do you think the Space shuttle or the Apollo astronauts knew where they were in space? They had a crude, very large "pixels" that noted when VERY bright stars were in their "bracket", excitable thin wires with a sensor material(semi conductor) adjacent.

Interesting. That's what a Geiger counter, or Proportional counter (the only difference is current in the wire) does. Photon hits thin highly conductive wire running a current and affects the current. Changes in the current are easy to detect (in our case an oscilloscope we scrounged old enough to use vacuum tubes and a Mac SE to capture the data it generated). Yeah, a semiconductor would work, although I'd expect there was a little more to it than that (transistor switches probably, feeding a primitive nav computer? Or did it just turn on a light and they did slide rule calcualtions?).

Doing it with starlight is cool. I'd have assumed it wouldn't be energetic enough. Was the wire actually outside the ship? We had to use incredibly thin aluminum walls on our counter to prevent high energy radiation from scattering from either interactions with container walls and messing up our results, but maybe that wouldn't matter so much in that application, if you just are shooting for contrast between "bright" and "not bright".