Simple Sensor Rules for CT (work in progress)

[Ptah]

Originally posted by WJP:
...

And, I haven't quite decided how to handle jammers yet.

How about something simple, they don't effect the chance to detect but they do effect the chance to determine what it is and to hit.

That is jammers put a "big blurry blob" (BBB)* on you sensor screen but you know something is out there and its general direction, but your not sure if its a destroyer or battleship, and you have lots of uncertainty in its actual position and vector -thus it is difficult to get a good fireing solution.

For CT, might roll jammers into all that tonnage for computers and the computer modifier.

*Normally a BBB, unless you are like the allies in WWII and can oh so slowly turn up the jamming so the enemy thinks its some natural phenomena or trouble with its equipment.

 

[Ptah]

Originally posted by WJP:
...

And, I haven't quite decided how to handle jammers yet.

How about something simple, they don't effect the chance to detect but they do effect the chance to determine what it is and to hit.

That is jammers put a "big blurry blob" (BBB)* on you sensor screen but you know something is out there and its general direction, but your not sure if its a destroyer or battleship, and you have lots of uncertainty in its actual position and vector -thus it is difficult to get a good fireing solution.

For CT, might roll jammers into all that tonnage for computers and the computer modifier.

*Normally a BBB, unless you are like the allies in WWII and can oh so slowly turn up the jamming so the enemy thinks its some natural phenomena or trouble with its equipment.

 

[Cymew]

WJP & Sigg,

Thanks for the run-down. Sometimes I don't "get it" from the rules and having someone phrase it differently makes a difference. That I don't all rules mentioned made it a bit confusing.

Now, maybe I shouldn't hijack the thread, but now I'd love to know at which range you place the ships. When do you know a closing ships is hostile anyway?

Maybe I should start a new thread...

 

[Cymew]

WJP & Sigg,

Thanks for the run-down. Sometimes I don't "get it" from the rules and having someone phrase it differently makes a difference. That I don't all rules mentioned made it a bit confusing.

Now, maybe I shouldn't hijack the thread, but now I'd love to know at which range you place the ships. When do you know a closing ships is hostile anyway?

Maybe I should start a new thread...

 

[Supplement Four]

Originally posted by Cymew:
Now, maybe I shouldn't hijack the thread, but now I'd love to know at which range you place the ships. When do you know a closing ships is hostile anyway?

These sensor rules should make it simple. When Passive sensors pick up a ship close to the player's ship, the PCs should keep an eye on it. Remember, Passive Sensors on civilian vessles will typically be less than 150,000 km--which really isn't that far out in astronomical terms.

Don't forget, too, that all ships have transponders that broadcast the ship's ID. I've seen it mentioned in Trav rules (may have been MT rules) where this transponder is broadcasting all the time (which will also increase detection range--making just about every contact detection "automatic" most of the time). The PCs can turn the transponder "off", but this is illegal most of the time (great idea to have the ship boarded by customs--when they're are running with their transponder off).

I've also seen it played where the transponder doesn't automatically broadcast (but that broadcasting all the time makes sense--like boating, you always want other ships to know where you are...if you're on the up and up), but it can be "pinged" by a vessel. If your ship is pinged, then you must reply with the transponder ID.

So, if the players' ship is being approached by a ship without a transponder signal, they should probably start to get worried.

Also, space is a big place. There should little reason for any other craft to come "close" to the PC's ship.

The PC's, reading the sensor data, can tell a ship's velocity (velocity being both speed and direction). If the projected flight path of a ship takes it anywhere near the PC's ship (say, within 150,000-200,000 km), then the PC's should keep an eye on it.

It should be very hard for any ship to sneak up on another in space.

Pirates can have false transponders (also, their ship configuration might give 'em away, "Hey, that's not a standard 200 ton Free Trader!"), or, if appropriate, they can hid behind asteroids in Trojan Points or Asteroid Belts.

Another place a ship can be vulnerable is when refueling at a Gas Giant. Diving into the upper atmo of a GG will screw with the sensors (all those magnetic fields and screwy atmo conditions), making the ship effectively blind while it scoops hydrogen.

Pirates and such could hide around the horizon of a GG then spring on any ship that is wilderness refueling, getting fairly close, if they're lucky, before the target ship realizes another vessel is close.

Check your LBB2 for weapon range. At 50 Range Bands (500,000 km), laser attacks are at -5DM, so that's a pretty safe distance. One of the jobs of the Navigator, on the PC's bridge, will be to monitor other vessels within 500,000 km of the PC's ship.

If it's a heavy traffic area, he won't be on guard as much as he would if the PCs are out all alone and a bogey shows up at 500,000 km. Keep an eye on that guy (and check his transponder).

So, to answer you question, I'd say "it depends" and give you a range of something like 150-000 km to 500,000 km. That will typically be a starting point for a ship encounter--somewhere in that range.

Anything closer than that is something the PCs should watch closely.

 

[Supplement Four]

Originally posted by Cymew:
Now, maybe I shouldn't hijack the thread, but now I'd love to know at which range you place the ships. When do you know a closing ships is hostile anyway?

These sensor rules should make it simple. When Passive sensors pick up a ship close to the player's ship, the PCs should keep an eye on it. Remember, Passive Sensors on civilian vessles will typically be less than 150,000 km--which really isn't that far out in astronomical terms.

Don't forget, too, that all ships have transponders that broadcast the ship's ID. I've seen it mentioned in Trav rules (may have been MT rules) where this transponder is broadcasting all the time (which will also increase detection range--making just about every contact detection "automatic" most of the time). The PCs can turn the transponder "off", but this is illegal most of the time (great idea to have the ship boarded by customs--when they're are running with their transponder off).

I've also seen it played where the transponder doesn't automatically broadcast (but that broadcasting all the time makes sense--like boating, you always want other ships to know where you are...if you're on the up and up), but it can be "pinged" by a vessel. If your ship is pinged, then you must reply with the transponder ID.

So, if the players' ship is being approached by a ship without a transponder signal, they should probably start to get worried.

Also, space is a big place. There should little reason for any other craft to come "close" to the PC's ship.

The PC's, reading the sensor data, can tell a ship's velocity (velocity being both speed and direction). If the projected flight path of a ship takes it anywhere near the PC's ship (say, within 150,000-200,000 km), then the PC's should keep an eye on it.

It should be very hard for any ship to sneak up on another in space.

Pirates can have false transponders (also, their ship configuration might give 'em away, "Hey, that's not a standard 200 ton Free Trader!"), or, if appropriate, they can hid behind asteroids in Trojan Points or Asteroid Belts.

Another place a ship can be vulnerable is when refueling at a Gas Giant. Diving into the upper atmo of a GG will screw with the sensors (all those magnetic fields and screwy atmo conditions), making the ship effectively blind while it scoops hydrogen.

Pirates and such could hide around the horizon of a GG then spring on any ship that is wilderness refueling, getting fairly close, if they're lucky, before the target ship realizes another vessel is close.

Check your LBB2 for weapon range. At 50 Range Bands (500,000 km), laser attacks are at -5DM, so that's a pretty safe distance. One of the jobs of the Navigator, on the PC's bridge, will be to monitor other vessels within 500,000 km of the PC's ship.

If it's a heavy traffic area, he won't be on guard as much as he would if the PCs are out all alone and a bogey shows up at 500,000 km. Keep an eye on that guy (and check his transponder).

So, to answer you question, I'd say "it depends" and give you a range of something like 150-000 km to 500,000 km. That will typically be a starting point for a ship encounter--somewhere in that range.

Anything closer than that is something the PCs should watch closely.

 

[Supplement Four]

Oh, and one more thing....

Missiles. They come in all shapes and sizes, but the "standard" Traveller missile is 6G6.

"6G6" means that the missile acts as if it were a ship with a 6G M-Drive, but it can change its velocity (usually always increasing it's velocity by max each round) a max of 6 times.

Special Supplement 3 said something like (IIRC) a missile will explode on a roll of 4+ once this max was reached.

Remember that missiles start with the velocity of the firing ship.

So, if you have a bogey moving at a velocity of 7, and it fires a missile (a typical missile), that missile will have a velicity of 13 on round 1, 19 on round 2, 25 on round 3, 31 on round 4, 37 on round 5, and 43 on round 6.

That 430,000 km...but we're also talking a flight time of 6000 seconds (over 1.5 hours).

In 1.5 hours, the PCs will have ample opportunity to detect an incoming missile--even with passive sensors (they'll have 6 tries at attempting the detection--if it were me, I'd roll this behind my screen each round then alert the PCs to the incoming missile, it's velocity and range, when the roll was successful).


Basically, what I'm saying here is that missiles are slow compared to lasers, but they have more range (lasers are -5DM at 50 Range Bands).

So....the distance a PC should keep an eye around the ship is a sphere around the ship from 150,000 km to 500,000 km.

 

[Supplement Four]

Oh, and one more thing....

Missiles. They come in all shapes and sizes, but the "standard" Traveller missile is 6G6.

"6G6" means that the missile acts as if it were a ship with a 6G M-Drive, but it can change its velocity (usually always increasing it's velocity by max each round) a max of 6 times.

Special Supplement 3 said something like (IIRC) a missile will explode on a roll of 4+ once this max was reached.

Remember that missiles start with the velocity of the firing ship.

So, if you have a bogey moving at a velocity of 7, and it fires a missile (a typical missile), that missile will have a velicity of 13 on round 1, 19 on round 2, 25 on round 3, 31 on round 4, 37 on round 5, and 43 on round 6.

That 430,000 km...but we're also talking a flight time of 6000 seconds (over 1.5 hours).

In 1.5 hours, the PCs will have ample opportunity to detect an incoming missile--even with passive sensors (they'll have 6 tries at attempting the detection--if it were me, I'd roll this behind my screen each round then alert the PCs to the incoming missile, it's velocity and range, when the roll was successful).


Basically, what I'm saying here is that missiles are slow compared to lasers, but they have more range (lasers are -5DM at 50 Range Bands).

So....the distance a PC should keep an eye around the ship is a sphere around the ship from 150,000 km to 500,000 km.

 

[Supplement Four]

Originally posted by WJP:
So, if you have a bogey moving at a velocity of 7, and it fires a missile (a typical missile), that missile will have a velicity of 13 on round 1, 19 on round 2, 25 on round 3, 31 on round 4, 37 on round 5, and 43 on round 6.

That 430,000 km...but we're also talking a flight time of 6000 seconds (over 1.5 hours).

This is misleading: The missile won't travel 430,000 km in 1.5 hours. It will travel 13 + 19 25 + 31 + 37 + 43 Range Bands in just over 1.5 hours. That's 1,680,000 km in 1.5 hours!

But, their sensors (given my rules) will probably (most likely) not be able to lock on at the range (a sensor lock is required for combat). It's have to be a very sensitive sensor (have a high Computer Model number and a low sensor task difficulty) and maybe some good DM's to make that roll--it can be done, but it's not that easy, and we're talking about a pretty hard roll even with military grade sensors.


========================================

 

[Supplement Four]

Originally posted by WJP:
So, if you have a bogey moving at a velocity of 7, and it fires a missile (a typical missile), that missile will have a velicity of 13 on round 1, 19 on round 2, 25 on round 3, 31 on round 4, 37 on round 5, and 43 on round 6.

That 430,000 km...but we're also talking a flight time of 6000 seconds (over 1.5 hours).

This is misleading: The missile won't travel 430,000 km in 1.5 hours. It will travel 13 + 19 25 + 31 + 37 + 43 Range Bands in just over 1.5 hours. That's 1,680,000 km in 1.5 hours!

But, their sensors (given my rules) will probably (most likely) not be able to lock on at the range (a sensor lock is required for combat). It's have to be a very sensitive sensor (have a high Computer Model number and a low sensor task difficulty) and maybe some good DM's to make that roll--it can be done, but it's not that easy, and we're talking about a pretty hard roll even with military grade sensors.


========================================

 

[Supplement Four]

What a cool idea for a Traveller starship combat scenario.

The PC's ship is attacked by incoming missiles. Since the PC's ship is a civilian ship, with civilian sensors, they don't have the sensing range to target (or even detect) where these missiles are coming from!

The missiles just start showing up on the Passive Sensors at about 100,000 km! And, the velocity of the missiles are so high that, once they are detected, the PC's ship has just the one round before the missile hits.

I'm going to have to store that idea for later use.

I like it.

 

[Supplement Four]

What a cool idea for a Traveller starship combat scenario.

The PC's ship is attacked by incoming missiles. Since the PC's ship is a civilian ship, with civilian sensors, they don't have the sensing range to target (or even detect) where these missiles are coming from!

The missiles just start showing up on the Passive Sensors at about 100,000 km! And, the velocity of the missiles are so high that, once they are detected, the PC's ship has just the one round before the missile hits.

I'm going to have to store that idea for later use.

I like it.

 

[Supplement Four]

Originally posted by Ptah:
How about something simple, they don't effect the chance to detect but they do effect the chance to determine what it is and to hit.

Jammers will probably make the ship doing the jamming easy to detect--since it's really going active with the jamming (like using extreme active sensors).

There are two schools of thought on gaming jammers.

--1-- Is that jammers will jam a target 100% pf the time, and there is no hope for the target to do anything about it (this is the type of jamming found in Striker).

--2-- Is that jammers will only make detection and lock rolls harder to make as the target ship must "punch through" the jamming (this is the type mostly used in starship gaming, seen in TNE, MT, Brilliant Lances, etc).


I'm a little more partial to 2 rather than 1.

I'm thinking that detection will be damn easy--many times automatic (especially if transponders are broadcasting).

But, detection doesn't mean the PC's ship will know what they've detected. They'll just have some energy readings (heat, maybe, picked up on HRT) and know "something is out there, probably a ship, but we don't know what size or configuration".

A sensor lock is needed for space combat--a lock being more detailed information on the target (more precicise location, radar cross section for hull shape and size, etc).


What I'm thinking is that jamming can be used to make sensor locks harder to obtain.

If sensors rolls are made every round, then jamming can be used as a defensive measure to add a penalty DM to the target ship--where it might fail to maintain it's lock on you....causing the target ship to spend a round trying to re-obtain the lock, saving you from one round of attacks.

I also feel that jammers should be separate units that must be installed--and that most civilian ships don't have them (most military vessels do).


And then, to consider, is that there are different types of jamming. There's the Big Blurry Blobs that you mention. There's the "noise" that interferes with sensors.

But also, jamming could also be "false echoes"...feeding the enemy ship false sensor info.

Jamming drones could also be used--fired as a missile that sends out signals intended to confound the enemy (maybe they're really hot, sending out much more heat--where they look like other ships on the enemy's sensors).


I think these jammers needed to be addressed separately, after these basic sensor rules are completed--mainly because most Traveller games deal with civilian vessels, and most civilian vessels aren't equipped with jammers anyway.

 

[Supplement Four]

Originally posted by Ptah:
How about something simple, they don't effect the chance to detect but they do effect the chance to determine what it is and to hit.

Jammers will probably make the ship doing the jamming easy to detect--since it's really going active with the jamming (like using extreme active sensors).

There are two schools of thought on gaming jammers.

--1-- Is that jammers will jam a target 100% pf the time, and there is no hope for the target to do anything about it (this is the type of jamming found in Striker).

--2-- Is that jammers will only make detection and lock rolls harder to make as the target ship must "punch through" the jamming (this is the type mostly used in starship gaming, seen in TNE, MT, Brilliant Lances, etc).


I'm a little more partial to 2 rather than 1.

I'm thinking that detection will be damn easy--many times automatic (especially if transponders are broadcasting).

But, detection doesn't mean the PC's ship will know what they've detected. They'll just have some energy readings (heat, maybe, picked up on HRT) and know "something is out there, probably a ship, but we don't know what size or configuration".

A sensor lock is needed for space combat--a lock being more detailed information on the target (more precicise location, radar cross section for hull shape and size, etc).


What I'm thinking is that jamming can be used to make sensor locks harder to obtain.

If sensors rolls are made every round, then jamming can be used as a defensive measure to add a penalty DM to the target ship--where it might fail to maintain it's lock on you....causing the target ship to spend a round trying to re-obtain the lock, saving you from one round of attacks.

I also feel that jammers should be separate units that must be installed--and that most civilian ships don't have them (most military vessels do).


And then, to consider, is that there are different types of jamming. There's the Big Blurry Blobs that you mention. There's the "noise" that interferes with sensors.

But also, jamming could also be "false echoes"...feeding the enemy ship false sensor info.

Jamming drones could also be used--fired as a missile that sends out signals intended to confound the enemy (maybe they're really hot, sending out much more heat--where they look like other ships on the enemy's sensors).


I think these jammers needed to be addressed separately, after these basic sensor rules are completed--mainly because most Traveller games deal with civilian vessels, and most civilian vessels aren't equipped with jammers anyway.

 

[mike wightman]

Originally posted by WJP:
"6G6" means that the missile acts as if it were a ship with a 6G M-Drive, but it can change its velocity (usually always increasing it's velocity by max each round) a max of 6 times.

Not quite.

A 6G6 missile can change its vector by a maximum of 6G.
It may use 1G six times or 6G once.

A 6G6 system can accelerate to a maximum of 6G per turn, and has enough fuel to reach 6G once. A 3G12 system can accelerate to a maximum of 3G in one turn, and has enough fuel to allow reaching 3G for four turns. The same missile could accelerate at 1G for 12 turns, or 2G for 6 turns.

 

[mike wightman]

Originally posted by WJP:
"6G6" means that the missile acts as if it were a ship with a 6G M-Drive, but it can change its velocity (usually always increasing it's velocity by max each round) a max of 6 times.

Not quite.

A 6G6 missile can change its vector by a maximum of 6G.
It may use 1G six times or 6G once.

A 6G6 system can accelerate to a maximum of 6G per turn, and has enough fuel to reach 6G once. A 3G12 system can accelerate to a maximum of 3G in one turn, and has enough fuel to allow reaching 3G for four turns. The same missile could accelerate at 1G for 12 turns, or 2G for 6 turns.

 

[Ptah]

Originally posted by WJP:

There are two schools of thought on gaming jammers.

--1-- Is that jammers will jam a target 100% pf the time, and there is no hope for the target to do anything about it (this is the type of jamming found in Striker).

--2-- Is that jammers will only make detection and lock rolls harder to make as the target ship must "punch through" the jamming (this is the type mostly used in starship gaming, seen in TNE, MT, Brilliant Lances, etc).


I'm a little more partial to 2 rather than 1.

I'm thinking that detection will be damn easy--many times automatic (especially if transponders are broadcasting).

......

Jamming drones could also be used--fired as a missile that sends out signals intended to confound the enemy (maybe they're really hot, sending out much more heat--where they look like other ships on the enemy's sensors).

I'm partial to the 2nd school of thought myself and the autodetection.

What of the idea of decoy/jamming drones being used as the interstellar version of a "smoke screen"? Such a drone may also be a good defensive measure for a merchant ship. Too move even more off topic.

 

[Ptah]

Originally posted by WJP:

There are two schools of thought on gaming jammers.

--1-- Is that jammers will jam a target 100% pf the time, and there is no hope for the target to do anything about it (this is the type of jamming found in Striker).

--2-- Is that jammers will only make detection and lock rolls harder to make as the target ship must "punch through" the jamming (this is the type mostly used in starship gaming, seen in TNE, MT, Brilliant Lances, etc).


I'm a little more partial to 2 rather than 1.

I'm thinking that detection will be damn easy--many times automatic (especially if transponders are broadcasting).

......

Jamming drones could also be used--fired as a missile that sends out signals intended to confound the enemy (maybe they're really hot, sending out much more heat--where they look like other ships on the enemy's sensors).

I'm partial to the 2nd school of thought myself and the autodetection.

What of the idea of decoy/jamming drones being used as the interstellar version of a "smoke screen"? Such a drone may also be a good defensive measure for a merchant ship. Too move even more off topic.

 

[Supplement Four]

Originally posted by Sigg Oddra:

A 6G6 missile can change its vector by a maximum of 6G.
It may use 1G six times or 6G once.

The cool thing about being wrong is that you learn something...and I just learned something I thought I knew about missiles.

I was looking at pg. 13 of Mayday, and I read it wrong--it was per "hex", not per "turn" as I thought it was.

I thought the range of missiles was a bit long...but I didn't question it too much.

Thanks for the correction, Sig.

 

[Supplement Four]

Originally posted by Sigg Oddra:

A 6G6 missile can change its vector by a maximum of 6G.
It may use 1G six times or 6G once.

The cool thing about being wrong is that you learn something...and I just learned something I thought I knew about missiles.

I was looking at pg. 13 of Mayday, and I read it wrong--it was per "hex", not per "turn" as I thought it was.

I thought the range of missiles was a bit long...but I didn't question it too much.

Thanks for the correction, Sig.