The speed of light and jump drives.

[shadowdragon]

thread ressurection at its finest

it could be done in T20 - model8 or model9 sensors have 1 and 2 parsec base ranges respectively. the resolution would be extremely poor but might give some details.

 

[savage]

your kiddin right

My bet is No.

We already know that radio wave distort by one light year. So aliens are not watching first run of the tonight show...or listening to ww2.

A free trader or something at 9 light days out? Nope, don't think so. Now a distortion of a jump window...or some other large energy signature might be behind 1-2 parsec sensors. Heck, you might be able to pick up planetary bodies..."look that's no moon." :rofl:

Good question. I like that one.

 

[shadowdragon]

how do we know radio distorts at 1 ly? i have never heard of that...not saying it isnt possible just havent herd it before.....

9 light days is only about 233,280,000,000 km whereas 1 pc is about 30,936,816,000,000 km, so 9 light days is about .75% of the model 8 sensors base range. being that close you should be able to pick out some tidbits of information.......

besides, with all the arguments that it is impossible to hide a starship in space, a battle should stand out like a flare. you cant have it both ways!:devil:

 

[aramis]

By 1LY, the background hiss in the radio frequency sub-spectrum used for TV will exceed any single currently broadcast signal, due to the inverse-square law alone.

That is, the received wattage from interstellar background will exceed that of the signal. It is possible to, using large baseline interferometry, find the signal several orders down but the needed separation gets pretty damned large to do so.

A battle as described in MT or TNE will be visible for several LY... with decreasing clarity due to the inverse-square law... and only in a window the legth of the battle at a time separation equal to the distance separation measured in C-units (IE, seconds for LS, years for LY).

Note: we pick up 20 watt transmissions from the Voyager probes at a distance of more than 108 AU... but only on the largest and most sensitive receivers (+80dB or greater).

note that at +80dB, that's x10⁸ increase in watts/m², and these receivers pick up microvolts received... note that, as a baseline, 1w hits 1mA/m at 313m. that means about 1/2694372801600506 the power it would hit at 313m... it actually presents about (if I did the math right) 2.3µA/m..., given a +35dB from the sending and +80 from the recieving end. at 1 LY, it's about 0.000007µA; a 10KW (5000x) would be about .003µA, assuming the same gain; but given that most radio antennae used for TV are +0dB, we drop that by 1/3100 or so, getting about 0.000011µA/m at the 31m DSA scopes... in short, not bloody much at 1LY.
warning: I'm doing math I can handle, but with numbers I'm not bloody sure of.


And, when your angular resolution drops below the apparent separation of the combattants, it's just a spike in the emitted light... a series of semi irregular pulses.

 

[samuelvss]

This is not a unique tactical problem*, and so here's this for a standard solution:

The scouts maintain redundant robotic listening posts throughout every system that does not have a full-time presence. (Hidden on myriad satellites, etc.) These are transmitters and recievers, but only transmit when cued to do so by an IN or IISS ship with a coded signal. An emergency signal is recorded, along with sensor data, the IN comes in, cues the listening post, gets the dope, sends ships jumping to the points of the compass, including the nearest X-boat node, and IN base with a J6 courier.

The next time the crew is in port, the sensor signature of their ship is plastered in every port security office. There is a Sector-wide BOLO for them, such that any governement ship, and indeed any helpful civilian ship who wants to bother with such things, can read the sign on their back stating, "I'm a frakken' pirate."

Hmmmm, rewards, bounty hunters, mercs between tickets.....the plot thickens.




*Indeed, one might argue that solving it would be the basis for the most economical and effective anti-piracy.

 

[shadowdragon]

thanks aramis- make me look like a bonehead. i forgot all about background hiss (and thats not distortion, just normal signal fade)
you numbers look ok, but i ain't gonna sweat it as your base distance was off by 99.25%- the range listed by the original poster was 9 lightdays, a significantly shorter distance in which any em transmissions will still be relatively high (as compared to an entire LY) but whether or not it would work as desired, i think the main point is - is this a valid technique for "seeing" the past?

samuelvss- consider that idea stolen- i like it!

oh- and aramis- wouldnt 80db be 8b? deci being 10, -1db being signal loss over 1/10th of a mile of standard copper telegraph line......i think we should work in units of measurement which keeps the base number less than 10 dont you? it certainly helps with the math for those of us who have a hard time with eleven+ with our shoes on:rofl:

 

[shadowdragon]

one more thing- let us discuss this angular resolution myth of yours....

trying to integrate the fact that size matters when sensors come online, but having a bit of trouble with the maths (was wearing shoes at the time) and the simple t20 modifiers seem so inaccurate and generalized (no comments from the peanut gallery thank you). so professor- any ideas?:devil:

 

[Supplement Four]

This is a fantastic idea. Somebody earlier in the thread said, "it was just a cool idea", or something to that effect. I agree.

I've read about this in science fiction novels, but the thought never occurred to me to apply it to Traveller (after 27 years of playing the game).

I have to agree, though, with most of the people above. It's a neat idea, and possible with the right equipment, but probably not possible for an Imperial Naval Captain and the equipment/time he has available.

First off, I agree, the detail level is too small. Watching a stellar phenomenon and watching a ship's laser fire from 9 parsecs out are two vastly different things. I don't know if the technology exists to detect laser fire at that distance in the Traveller universe.



I have an alternate idea, though.

What about radio broadcast?

A Mayday, or Pirate-to-Victim communication?

Jumping out and catching a comm broadcast would be much easier and much more practical.

Let's say standard procedure is to record and broadcast pirate attacks (seems logical to me) along with the Mayday.

The IN Captain could jump out, catch the radio broadcast (hopefully with the victim's sensor data and maybe close range video) of the attacking ship.





If you think about the distances involved, even in a star system, most pirate attacks in the Traveller universe must happen in view of other vessels, starports, etc. The problem is, they're just too far away to do anything about it.

Let's say a ship is refuelling at the local GG and gets set upon by pirates. The GG is 300,000,000 km to the starport/world and 100,000,000 km to the nearest ship.

The comm delay to the planet is about 26 minutes, and it's about a 9 minute delay to the nearest ship.

The problem is, depending on the nearest ship's velocity and M-Drive, there's probably no way for the nearest ship to alter course and rendevous with the attacked ship before the attack is over.

But, they got full video and sensor data of the pirate. It happened in "broad day light" so to speak. It's just that, no one can do anything about it. No ship can intercept.





In game terms: Victim ship gets attacked by Pirates in far orbit of the GG. Closest Vessel is heading away from the GG towards the main world, at a velocity of 12 (120,000 km per Book 2 turn). The Closest Vessel has an M-Drive rating of 2. That means it will take it over an hour and a half (6000 seconds) to even bring the Closest Vessel around to where it can start accelerating towards the Victim.

That's 6 space combat rounds right there for the pirates to do their thing on the Victim.

Then, the Closest Vessel has to accelerate out to rendevous with the Victim. And, the Closest Vessel can't just go full-out through the entire trip because it has to match vectors with those ships in the fight. Basically, it has to accelerate full out for half the distance and then decelerate to match vectors for the second half of the trip.

The Closest Vessel would be 100,300,000 km away from the Victim before it could even start to accelerate in the Victim's direction.

See what I mean?

Most pirate attacks in the Traveller universe must have those that see it take place--they just can't do anything about the attack due to the distances involved.

Eyeballing the charts in The Traveller Book, it would take the Closest Vessel well over 45 hours to rendevous with the Victim vessel, giving the priates almost two whole days to cripple the Victim and strip it of its wares, and then get away...all in full view of the main world and other ships in the system. Heck, the pirates could even take the time to top off their fuel tanks at the GG, if they wanted.

 

[Supplement Four]

Most pirate attacks in the Traveller universe must have those that see it take place--they just can't do anything about the attack due to the distances involved.

In my Traveller campaign from two years ago, I ran a scenario similar to this. The players were being attacked. The main world was in an asteroid system, so standard procedure was to exit jump outside the belt and make the journey to the main world.

The players' ship was being attacked, and they set out a mayday. With some lag, they were in communication with the main world.

The closest vessel was heading from the main world, though the belt, in order to jump to its destination.

Well, I figured the ship's velocity, having left the main world and intersecting the path of the players' ship. This vessel was moving so fast by the time it intersected with the players' ship that there was no way it could slow down and help the players in time.

As luck would have it, though, the closest vessel would be in weapons range for exactly two combat rounds before the ship itself was out of range.

It was kinda neat, that game. The players were in constant communication with the closest vessel. The players were acting out their last will and testaments to the people on the other ship. The two rounds came and went, and the pirates were still pounding away on the players' ship, blowing off bits of it here and there.

And, the crew of the Closest Vessel had this record of what was happening...but they could do nothing but record it.

Cool game.

 

[aramis]

oh- and aramis- wouldnt 80db be 8b? deci being 10, -1db being signal loss over 1/10th of a mile of standard copper telegraph line......i think we should work in units of measurement which keeps the base number less than 10 dont you? it certainly helps with the math for those of us who have a hard time with eleven+ with our shoes on:rofl:

Yes, but unless you're a real überübergeek, you're not going to measure anything in bels, and many of the uses are not calibrated in bels, only in decibels...

according to rowlett's:

bel (B)
a logarithmic measure of sound intensity, invented by engineers of the Bell telephone network in 1923 and named in honor of the inventor of the telephone, Alexander Graham Bell (1847-1922). If one sound is 1 bel louder than another, this means the louder sound is 10 times more intense than the fainter one. A difference of 2 bels corresponds to an increase of 10 x 10 or 100 times in intensity. The beginning of the scale, 0 bels, can be defined in various ways (see decibel) originally intended to represent the faintest sound that can be detected by a person who has good hearing. In practice, sound intensity is almost always stated in decibels. One bel is equal to approximately 1.151 293 nepers.​

http://www.unc.edu/~rowlett/units/dictB.html

dB -
a symbol indicating that a measurement is made using a logarithmic scale similar to that of the decibel (see below) in that a difference of 10 dB- corresponds to a factor of 10. In each case, the actual measurement a is compared to a fixed reference level r and the "decibel" value is defined to be 10 log10(a/r). Many units of this kind have been used and only a few of the more common ones are mentioned in the next entries. In each case the dB symbol is followed by a second symbol identifying the specific measurement. Often the two symbols are not separated (as in "dBA"), but the Audio Engineering Society recommends that a space be used (as in "dB A").
dB A, dB C
units of sound intensity, exactly like the decibel except that before the measurement is made sounds of high and low frequencies, heard poorly or not at all by the human ear, have been filtered out. The letters A and C refer to two filtering methods.
dB c
a unit of signal strength used in electronics, especially in measuring noise levels. The signals are measured relative to the strength of the carrier signal, which is the desired signal. A typical statement might be that a certain noise level is -50 dB c, meaning that the noise is 50 "decibels below carrier" or 10-5 times the carrier signal strength.
dB FS
abbreviation for "decibels full scale," a unit of power as measured by a digital device. A digital measurement has a maximum value M depending on the number of bits used. If the actual power measurement is p, the dB FS value displayed is 20·log10(p/M) dB FS. Since p cannot exceed M, this reading is always negative.
dB i
a unit measuring the gain of an antenna. The reference level is the strength of the signal that would be transmitted by an isotropic antenna: one radiating equally in all directions. For example, an antenna rated 20 dB i transmits a signal in the desired direction 102 = 100 times stronger than an isotropic antenna.
dB m, dB W
logarithmic units of power used in electronics. These units measure power in decibels above the reference level of 1 milliwatt in the case of dB m and 1 watt in the case of dB W. A power of n watts equals 10 log n dB W; conversely, a power of p dB W equals 10(p/10) watts. The same formulas link dB m to milliwatts. An increase of 10 dB m or 10 dB W represents a 10-fold increase in power. Since 1 watt = 1000 milliwatts, 0 dB W = 30 dB m.
dB rn
a symbol for "decibels above reference noise," a unit measuring noise levels in telecommunications. The usual reference level is -90 dB m, which is equivalent to a power of 1 picowatt (1 pW). For example, 50 dB rn equals -40 dB m.
dB spl
a logarithmic unit of sound intensity as computed from the sound pressure level. The reference level is a pressure of 20 micropascals. If sound waves exert a pressure of P pascals, the sound intensity is 100 + 20·log10(P/2) dB spl.
dB u
a logarithmic unit of power, similar to dB m but computed from voltage measurements. The reference level is 0.775 volts, the voltage which generates a power of 1 milliwatt across a circuit having an impedance of 600 ohms. A voltage of V volts corresponds to a power of 20·log10(V/0.775) dB u.
dB V
a logarithmic unit of power, similar to dB m but computed from voltage measurements. The reference level is 1 volt. A voltage of V volts corresponds to a power of 20·log10(V) dB V.
dB W
see dB m above.
dB Z
a unit of radar reflectivity used in meteorology. The unit measures the amount of energy returned to a weather radar site as a function of the amount transmitted. The scale is logarithmic, a difference of 10 dB Z indicating a 10-fold increase in energy returned. For display purposes, dB Z values are grouped as follows:
(Level 1, 18-30 dBZ) - Light precipitation
(Level 2, 30-38 dBZ) - Light to moderate rain
(Level 3, 38-44 dBZ) - Moderate to heavy rain
(Level 4, 44-50 dBZ) - Heavy rain
(Level 5, 50-57 dBZ) - Very heavy rain; hail possible
(Level 6, >57 dBZ) - Very heavy rain and hail; large hail possible
The colorful "radar images" shown on television are actually plots of these levels.​

http://www.travellerrpg.com/CotI/Discuss/newreply.php?do=newreply&p=314507

So, between inverse square, receiver-generated RFI, and background radio hiss, at 1 LY, you're not going to pick up TV signal from a 10KW "Superstation" with a 30m radio antenna; you might notice a deflection from baseline, and be able to DF, but I don't remember the baseline hiss levels.

Note that optics can be described the exact same way (even tho' they normally are not).

 

[savage]

big bang

So, between inverse square, receiver-generated RFI, and background radio hiss, at 1 LY, you're not going to pick up TV signal from a 10KW "Superstation" with a 30m radio antenna; you might notice a deflection from baseline, and be able to DF, but I don't remember the baseline hiss levels.

Note that optics can be described the exact same way (even tho' they normally are not).

So we're talking louder than the big bang, as i recall from the article, to hear anything... so lets change direction.

what do sensors do is the real question right? If hubble cannot see the details of the habitable zone of Apha Centauri-AB. I'd say we're only looking for energy signatures with our type T cruiser or Gazelle.
Or better yet you jump away from the Star... so it is the background and use the same tech they use to find planets... hmmm would that work?
All we really want to know is where the energy sigs went.... i use vectors in my universe. You don't aim trailing if your going to jump to a world coreward.

Now what about triangulation software could a bunch of T cruisers figure out where the kidnaped Countess went by setting up an array of sorts? Because I need a better reason to do this than tracking Beowulf.

Or we could go back to work arounds and detect tacyons which all matter affects. And how does dark matter impact our efforts. Could a type T do this.

Why do we have 2 parsec sensors. energy detection. "Sir, multiple signatures at .5 parsecs calculating travel elapse time..."

Time for a spoon of peanut butter... yum :frankie:

 

[aramis]

A 2Pc sensor is going to be able to pick up a ship's signature (which is considerably higher than many asteroids) at 2Pc IF it happens to be
1) aiming for the right 0.1 sec of arc
2) 6.52 years after the ship was there
3) not lost in the solar glare
4) using the IR/vis/NUV spectrum (which is remarably low background "hiss")

What it isn't going to do is identify the ship, hear the radio transmissions Tho a large enough sensor could pick up that there were transmissions; the data is essentially lost to the noise.

Note that the flare of the Apollo lander's main engine was visible from earth; the lander itself isn't.

Also note that sensors past 500,000,000m are passive under MT and TNE. The passive EMS could be a pair of 1m dishes with very narrow focus (1 sec of arc, 1/3600 of a degree...) thus giving a 30m baseline for a ship, and 2 1m dishes, the ability to use interferometry in the vis/NIR/NUV spectra, and about +60dB, with a -120dB sensitivity...

lets punch in 2 Pc/313m... 1/1.86e28 or about -283dB. given 1mv/m as 0dB, and 40kW is 16dB source... and a 60dB gain, 16+60=78, 78-283=-205dB sensitivity on that TL10 PEMS 2Pc if it detects a system radio comm; a free trader should have, not counting inefficiency of drives, at least a +83dB signature (500Mw useful power), given the inefficiency of fuel, call it probably a safe bet of +90... so we can presume if the standard is detecting a small starship at 2Pc, a sensitivity of 90+60-283=-133dB, (which is about what the sensitivity for top end radios currently is... making me feel much better about the numbers in use). If we instead go with a larger ship, say 50tons PP, and +10dB for inefficiency, we get +110dB source, and -103dB sensitivity, which feels right for a 1m pair interferometer. the biggest ships peak out at about 145dB...

 

[skyth]

With the amount of piracy in the TU (According to the encounter charts in book 2 - 1/12 of encounters for a type C startport...1/6 if there is both a naval and a scout base in system ) ), I doubt it would be this easy to track pirates.

Granted, decent pirates would have a catch and carry system.

 

[Whipsnade]

With the amount of piracy in the TU (According to the encounter charts in book 2 - 1/12 of encounters for a type C startport...1/6 if there is both a naval and a scout base in system ) ), I doubt it would be this easy to track pirates.

Syth,

Read that table again. The rolls you're referring to only result in pirate encounters IF the GM decides they do.

The table also states that it used, and I'm paraphrasing here, when "...the players are going about their business". You'll notice that isn't exactly the same as "Traveling from port to jump limit".

Granted, decent pirates would have a catch and carry system.

A catch and carry system means you have to catch first. May I suggest you pull out LBB:2 or Mayday and see how difficult matching vectors in two dimensions can be?


Regards,
Bill

 

[rancke]

The table also states that it used, and I'm paraphrasing here, when "...the players are going about their business". You'll notice that isn't exactly the same as "Traveling from port to jump limit".

Unless the PCs are engaged in trade as per the Traveller trade system. If they are, there is no such thing as in-system travel.


Hans

 

[skyth]

Syth,

Read that table again. The rolls you're referring to only result in pirate encounters IF the GM decides they do.

Use of the table is only if the GM decides to do so (Just like ALL rules). But the P results are to be contrued as pirates and will likely attack or try to. This gives an indication of the frequency of pirates in the OTU.

A catch and carry system means you have to catch first. May I suggest you pull out LBB:2 or Mayday and see how difficult matching vectors in two dimensions can be?

You are misinterpreting what the catch and carry system is...You have two ships...One to catch the prey, the other to carry the stolen goods elsewhere and sell them.

 

[rancke]

You are misinterpreting what the catch and carry system is...You have two ships...One to catch the prey, the other to carry the stolen goods elsewhere and sell them.

Bill is pointing out that you won't get anything to carry if you can't catch.



Hans

 

[skyth]

Against a non-maneuvering ship (For any reason) it shouldn't be that hard, especially with computer help.

 

[Whipsnade]

This gives an indication of the frequency of pirates in the OTU.

Skyth,

It indicates nothing of the sort because whether a pirate attack occurs or not is entirely up to the GM to decide. When GM fiat is involved nothing can be learned about the "fictional reality" within a setting.

You are misinterpreting what the catch and carry system is...You have two ships...One to catch the prey, the other to carry the stolen goods elsewhere and sell them.

I do understand what "catch and carry" means, but you don't seem to understand that the first part of "catch and carry" is catch. Whether two or twenty two ships are involved, it doesn't matter if the "catch" never occurs.

Don't believe me? Take out any of Traveller's vector based ship combat systems, set up a scenario, and see how long it takes to rendezvous and dock with another ship. It's quite an eye opener.


Regards,
Bill

 

[aramis]

Actually, the P means the ship is willing to pirate, depending upon the reaction roll. Ok, it says the P "may be construed as" a pirate. It also says the Referee "may want to determine" their specific reaction by the reactions table. If a pirate isn't hostile, he's either wary of you, of the local gendarmery, or has full holds, or short crew, or whatever...