Inbound System Comms

[OriginalCaruso]

I’m sure GMs already have their own way of handling communications between ships inbound and outbound from jump points but thought I’d draft a few notes used IMTU which draw from my ex military background.

In real life, there are two communication bands used by civil and military, VHF and UHF. Within these two bands there are guard frequencies 121.5 MHz and 243.0 MHz. Never broadcast on these frequencies unless you want a very unfriendly knock on the door, your location will be pinpointed.

In Traveller, I use the guard frequencies for emergency comms such as distress calls etc. adds a bit of flavour when role playing.

Transponders are another feature which can be used to player advantage. During last nights session I discovered rules within Secrets of the Ancients ~pg71 on how to disguise a ships transponder message, first a brief digression into the real world on how transponders actually work.

RADAR is (or was back in my day) categorised as Primary and Secondary. A Primary RADAR has a very narrow focus beam delivering both range and height information to a display. When a target is detected, the Secondary radar knows this information and sends a coded pulse to the target via a beam offset from the Primary RADAR. The Secondary return provides contextual information from the aircraft transponder - commonly known as a Squawk code. The Squawk code contains aircraft information and pilot set codes indicating hijack state etc.

In Traveller, I use the above concepts to allow pilots to indicate state. Also, according to the rules discovered during last nights game, I now allow subterfuge by masking transponder output.

I hope someone finds this useful

 

[ResslynHalvik]

Thank you for taking me back down memory lane to the days when I would be directed by ATC to eg "squawk 7040 with ident"

 

[Condottiere]

 

[MasterGwydion]

I’m sure GMs already have their own way of handling communications between ships inbound and outbound from jump points but thought I’d draft a few notes used IMTU which draw from my ex military background.

In real life, there are two communication bands used by civil and military, VHF and UHF. Within these two bands there are guard frequencies 121.5 MHz and 243.0 MHz. Never broadcast on these frequencies unless you want a very unfriendly knock on the door, your location will be pinpointed.

In Traveller, I use the guard frequencies for emergency comms such as distress calls etc. adds a bit of flavour when role playing.

Transponders are another feature which can be used to player advantage. During last nights session I discovered rules within Secrets of the Ancients ~pg71 on how to disguise a ships transponder message, first a brief digression into the real world on how transponders actually work.

RADAR is (or was back in my day) categorised as Primary and Secondary. A Primary RADAR has a very narrow focus beam delivering both range and height information to a display. When a target is detected, the Secondary radar knows this information and sends a coded pulse to the target via a beam offset from the Primary RADAR. The Secondary return provides contextual information from the aircraft transponder - commonly known as a Squawk code. The Squawk code contains aircraft information and pilot set codes indicating hijack state etc.

In Traveller, I use the above concepts to allow pilots to indicate state. Also, according to the rules discovered during last nights game, I now allow subterfuge by masking transponder output.

I hope someone finds this useful

Check out the Traveller Companion, pages 165-166. It has some info on Transponders.

 

[phavoc]

I’m sure GMs already have their own way of handling communications between ships inbound and outbound from jump points but thought I’d draft a few notes used IMTU which draw from my ex military background.

In real life, there are two communication bands used by civil and military, VHF and UHF. Within these two bands there are guard frequencies 121.5 MHz and 243.0 MHz. Never broadcast on these frequencies unless you want a very unfriendly knock on the door, your location will be pinpointed.

In Traveller, I use the guard frequencies for emergency comms such as distress calls etc. adds a bit of flavour when role playing.

Transponders are another feature which can be used to player advantage. During last nights session I discovered rules within Secrets of the Ancients ~pg71 on how to disguise a ships transponder message, first a brief digression into the real world on how transponders actually work.

RADAR is (or was back in my day) categorised as Primary and Secondary. A Primary RADAR has a very narrow focus beam delivering both range and height information to a display. When a target is detected, the Secondary radar knows this information and sends a coded pulse to the target via a beam offset from the Primary RADAR. The Secondary return provides contextual information from the aircraft transponder - commonly known as a Squawk code. The Squawk code contains aircraft information and pilot set codes indicating hijack state etc.

In Traveller, I use the above concepts to allow pilots to indicate state. Also, according to the rules discovered during last nights game, I now allow subterfuge by masking transponder output.

I hope someone finds this useful

I would expect in space that your transponder is continually broadcasting ship information, heading and speed. Space is pretty vast and active sensors may not work - though admittedly it may be childs play by the 52nd century and having 360 passive/active sensors working all the time would be easy. But I'd think most sensors would be passive as being active requires energy and lights you up for everyone else to see. Not a bad thing for someone who wants to be seen, but otherwise it seems like a different sort of problem if every ship is constant with active emissions - especially in crowded planetary orbits.

Of course that does mean a ship that wants to stay off the grid would simply shut down their transponder so that they aren't actively broadcasting their location/heading. Which would work for lots of the area of a star system. Only certain areas (the main world probably) will have any sort of network of active sensors looking for inbound vessels. Everything else would expect to rely upon passive scans unless something occurs to have them go active. Obviously the Imperial and planetary authorities would take a very dim view of any vessel traversing their system w/o an active transponder and assume they are (probably) up to no good. I don't expect any of them to fire upon a vessel without a challenge first unless it's wartime - and even then they'd not want to blow up civilian ships that have defective/damaged transponders.

 

[MarcusIII]

Passively scanning a system looking for active ships even using tech from 2,000 A.D. is a trivial task for system traffic control. It takes a relatively long time to traverse a solar system or a portion of it using a maneuver drive of any kind. So once a ship or moving object is spotted it will be known if it is squawking like it should. Measures can be taken if it isn't.

 

[phavoc]

Passively scanning a system looking for active ships even using tech from 2,000 A.D. is a trivial task for system traffic control. It takes a relatively long time to traverse a solar system or a portion of it using a maneuver drive of any kind. So once a ship or moving object is spotted it will be known if it is squawking like it should. Measures can be taken if it isn't.

A star system is a vast place. Active sensors have a limited range, passive greater, but even then they have limitations. The gravitic sensors in the one expansion would mean that all ships would be trackable, even light-years away. However they also break canon and I don't think they belong in the game. Its an example of something being introduced that was not well thought-out (IMO).

 

[MasterGwydion]

A star system is a vast place. Active sensors have a limited range, passive greater, but even then they have limitations. The gravitic sensors in the one expansion would mean that all ships would be trackable, even light-years away. However they also break canon and I don't think they belong in the game. Its an example of something being introduced that was not well thought-out (IMO).

They do break Canon by allowing one gravity sensor to automatically detect all jump activity (except Stealth Jump) within range, usually several parsecs. Does that actually break Canon though? You still are only getting the information at the speed of light. You can detect every jump within a 1 parsec radius, but you won't get that information until over 3 years have passed at a full parsec of distance.

 

[Terry Mixon]

They do break Canon by allowing one gravity sensor to automatically detect all jump activity (except Stealth Jump) within range, usually several parsecs. Does that actually break Canon though? You still are only getting the information at the speed of light. You can detect every jump within a 1 parsec radius, but you won't get that information until over 3 years have passed at a full parsec of distance.

It's a serious glitch that @paltrysum needs to rectify in the next High Guard Update.

 

[MasterGwydion]

It's a serious glitch that @paltrysum needs to rectify in the next High Guard Update.

Does it do more than just give a view into past jumps?

 

[Terry Mixon]

Does it do more than just give a view into past jumps?

No, but even a few parsecs is too far. My brain tells me its more than that, though. It's telling me there isn't a limit to the detection jump flashes. Tell me I'm wrong, please because that's crazy.

 

[MasterGwydion]

Difficulty 10 +1/multiple of the Automatic Detection Range.

So figure out the maximum bonus you can get on an Electronics (sensors) roll. That should give you both the maximum range as well as the average detection range. Just remember, that outside of the automatic detection range, it requires actively searching, so anything beyond Automatic Detection Range should require a group of sensor operators around the clock searching for jump flashes more than a parsec away.

 

[Terry Mixon]

View attachment 6305
Difficulty 10 +1/multiple of the Automatic Detection Range.

So figure out the maximum bonus you can get on an Electronics (sensors) roll. That should give you both the maximum range as well as the average detection range. Just remember, that outside of the automatic detection range, it requires actively searching, so anything beyond Automatic Detection Range should require a group of sensor operators around the clock searching for jump flashes more than a parsec away.

Okay, it’s not infinite, so I’m overly concerned. Whew.

Difficult 10+ roll with a DM-1 for each multiple of 1 parsec. Three parsecs is 12+ roll. Got it. I can live with that.

 

[Condottiere]

Seismic detection.

One assumes you need bigger disruption of the time space continuum, to be able to detect jump flashes at a distance.

 

[MarcusIII]

passive greater, but even then they have limitations.

Passive IR can nail any ship in system easily. Unless it's hiding behind a body in relation to the sensor. Basic physics. It's like starting a bonfire on a totally dark plain at night. You're detected as soon as the light hits the sensor. Period

 

[OriginalCaruso]

Passive IR can nail any ship in system easily. Unless it's hiding behind a body in relation to the sensor. Basic physics. It's like starting a bonfire on a totally dark plain at night. You're detected as soon as the light hits the sensor. Period

Assuming the detector is point in the right direction, the heat source is sufficient to register on the detector, an event is raised and someone looks at the event...

 

[MarcusIII]

Assuming the detector is point in the right direction, the heat source is sufficient to register on the detector, an event is raised and someone looks at the event...

No, the sensors scans the ENTIRE spherical space by moving. Can be done with off the shelf tech from the 20th century that any person could buy. So automatic equipment for any space faring civilization.

 

[swordtart]

No, the sensors scans the ENTIRE spherical space by moving. Can be done with off the shelf tech from the 20th century that any person could buy. So automatic equipment for any space faring civilization.

I'd be interested in seeing that shelf.

 

[MarcusIII]

I'd be interested in seeing that shelf.

If you were into computer 25 years ago you'd have seen it. FAR more powerful stuff exists today

 

[swordtart]

If you were into computer 25 years ago you'd have seen it. FAR more powerful stuff exists today

There was a system that could scan the entire volume of a spherical space half a million km in diameter in 6 minutes?