Relay Networks in 1.2

[knotcher]

Like I usually do, I started implementing my plan before checking with the experts. Let me know if my simplified relay network has any giant holes in it to start. I just used a cargo plan to deposit "satellites" at the poles. I intend to place one in geostationary directly above KSC and one directly opposite. The only coverage gap I am worried about to start is a band that goes all the way around kerbin halfway between the sats. What else am I missing? (I disabled kerbin relays)

Edited November 20, 2016 by knotcher

[Geschosskopf]

17 hours ago, knotcher said:

Like I usually do, I started implementing my plan before checking with the experts. Let me know if my simplified relay network has any giant holes in it to start. I just used a cargo plan to deposit "satellites" at the poles. I intend to place one in geostationary directly above KSC and one directly opposite. The only coverage gap I am worried about to start is a band that goes all the way around kerbin halfway between the sats. What else am I missing? (I disabled kerbin relays)

Well, if you're committed to the illogical RT-like paradigm where Kerbals colonize other planets before they spread over the surface of their own, then hey, that's your business .

Anyway, the bottom line of disabling the other ground-based antennae on Kerbin is that you just have to replicate them in space.  Because KSC will be facing away from your distant ship about 1/2 the time, that ship must talk to a relay over the side of Kerbin facing it, and that relay must then relay around Kerbin via other satellites to KSC.  The traditional way of doing this in RT is to put up a geostationary network of 3 satelliets, 1 directly over KSC and the others 120^ to either side.  3 geostationary satellites is the minimum required to be able to talk around Kerbin from one to the next without Kerbin getting in the way.

If I understand you correctly, you have built ground stations at the poles.  Those will only be able to see the geostationary satellites in equatorial orbit if you leave occlusion at the default level of less than 100%.  If you set occlusion to 100%, then I doubt your system will work at all.  If you're going to disable the ground antennae, why not do this as well?  In any case, you'd be better served with 3 geostationary satellites and nothing else.  Then you wouldn't have the potential blind spot.

KSC claims to have improved its orbital mechanics recently but in my experience, it's still impossible to put satellites in exactly the orbit you want.  The important variable for geostationary satellites is orbital period and this just isn't constant to the precision you need (which was always the Achilles' Heel of Remote Tech).. So I prefer to do without this hassle and use the additional ground-based stations.  After all, we had trans-oceanic cables nearly a century before Apollo 11.

[Etaparseids]

For some reason, my satellites will not communicate with each other. Have relay antennas on them all, have LOS to each other, not sure what I'm doing wrong....

[Geschosskopf]

On 11/23/2016 at 7:06 PM, Etaparseids said:

For some reason, my satellites will not communicate with each other. Have relay antennas on them all, have LOS to each other, not sure what I'm doing wrong....

 Well, there are several possibilities:  1) you haven't set the map view to show any links, 2) you disabled the entire need for networks in the settings, 3) the antenna are out of range of each other, or 4) you disabled the other ground-based antenna on Kerbin so can only talk to KSC itself, and KSC is facing away from your satellites.

But regardless of that, don't think of your network as satellites communicating with each other.  It doesn't work like that.  It's always KSC communicating (or not) with the active vessel.  Any relay satellites in between KSC and the active vessel are best thought of as mere telephone poles along this path.  They don't really participate in the conversation between KSC and the active vessel, they just enable it to happen.

Understand that the ground-based antennae on Kerbin are always going to be your best, and they are actually all you need for a large portion of the total mission time.  If you have NOT disabled the extra-KSC ground antennae, then the time of day at KSC doesn't matter because you're talking to Kerbin as a whole, not just KSC.  Thus, most of the time, there's a clear LOS between Kerbin and your active vessel and you only need relays to provide bank shots around the odd intervening heavenly body, or to talk to the farside of Mun.  If you DID disable the other ground antennae, then you just have to replicate them in space with some sort of kerbo-synchronous or -stationary relay network around Kerbin, which faces in all direction and links to KSC.  Once you do that, it's the same story as before.  You;'re still talking to Kerbin as a whole and only need relays to talk around other heavenly bodies when they get in the way.

Make sure you understand the differences between antenna types, too:

Direct Antennae

• All the old stock antennae and the new dipole
• Can ONLY link to KSC, other ground antennae on Kerbin, or relay antennae on other ships.
• Can NOT link to direct antennae on other ships.

Relay Antennae

• All the new ones (except the dipole) added in 1.2
• Can link to ANYTHING:  KSC, other Kerbin ground antennae, relay antennae on other ships, and direct antennae on other ships.

So let's say you have a lander on what is currently the far side of Duna.  For this lander to transmit science back to KSC, you need the following:

• Medium-range direct antenna on lander.  This links to...
• Short-range relay antenna in fairly low equatorial orbit at Duna.  This is so you can ignore the time of day on Duna.  This links to....
• Long-range relay antenna in highly eccentric polar orbit at Duna.  This is so you can ignore Ike being between Duna and Kerbin.  This links to....
• OPTIONAL:  Long-range relay antenna in highly eccentric polar orbit of Eve or Dres.  This is so you can bank around the sun when it's between Duna and Kerbin.  This links to....
• Long-range relay antenna in highly eccentric polar orbit at Kerbin.  This is so you can ignore Mun when it's between Kerbin and wherever the transmission is coming from.  This links to...
• OPTIONAL:  1 or more Short-range relay antenna in synchronous or stationary equatorial orbit at Kerbin.  This is ONLY if you've disabled the non-KSC ground antennae and thus have to form links around Kerbin itself when KSC is facing away from the active vessel.  If they're in Kerbostationary orbit, you need 3 of these and will use 1 or 2 at any given time.  If you left the non-KSC ground antenna enabled (which is the default), then you don't need this step.  Anyway, these link to....
• KSC (either via the optional network above or via trans-oceanic cables from one of the non-KSC ground antenna to KSC.

Did that answer your question?

 

[seeingeyegod]

Anyone have a clue why I have no probe control over my probe that currently has a network connection to KSC? I have electricity. Is there a control limit to the number of hops or something? The connection line to my probe that has no control goes through 2 hops before it reaches KSC. The close one is green and the second one red, but it is a connection. I don't get it

[edit] okay it appears that you just have limited probe control with weak signal, and also NO signal, as long as you have a probe core and electricity, and the only thing having a connection is REALLY important for is sending back science. I still think it is kind of misleading that the network will show a connection on the map but it isn't a strong enough one for control which will make the commnet indicator say NO CONNECTION even though you technically still have one.

Edited December 14, 2016 by seeingeyegod

[Breizhad]

On 21.11.2016 at 2:42 AM, Geschosskopf said:

Well, if you're committed to the illogical RT-like paradigm where Kerbals colonize other planets before they spread over the surface of their own, then hey, that's your business .

For the sake of argument I'd like to make a counter-point: AFAIK there are relay stations on earth (IRL) to talk to spacecraft, but the communication between those stations is handled via satellites. (Or was handled until the advent of high bandwith landlines) So in the game you should be forced to launch such satellites into orbit before you're able to use the extra ground stations. Or am I mistaken?

On 21.11.2016 at 2:42 AM, Geschosskopf said:

Anyway, the bottom line of disabling the other ground-based antennae on Kerbin is that you just have to replicate them in space.  Because KSC will be facing away from your distant ship about 1/2 the time, that ship must talk to a relay over the side of Kerbin facing it, and that relay must then relay around Kerbin via other satellites to KSC.  The traditional way of doing this in RT is to put up a geostationary network of 3 satelliets, 1 directly over KSC and the others 120^ to either side.  3 geostationary satellites is the minimum required to be able to talk around Kerbin from one to the next without Kerbin getting in the way.

Why geostationary? Geostationary (or better: kerbostationary) satellites are only required if you have fixed dishes on the ground. Since all Antennae in KSP are tracking their target, you don't need the satellite to stay in its place from the ground dish's point of view. What you must do instead is ensure 100% coverage. That is done by 3 Satellites phased at 120° from each other in high enough orbits, as you pointed out.

By the way: Thanks for the hint to occlusion @Geschosskopf, I didn't know about that feature and was confused and annoyed that I got LOS below the horizon. In case you haven't figured it out yet: I play with no extra ground stations.

That being said, I love your guide and I will try the eccentric polar relay concept for my own campaign. Thank you for sharing!

Finally, one idea of my own to expand your concept: In order to avoid Kerbin from being blocked by the sun, I'd use two relay satellites on solar orbits, with the same orbit as Kerbin but phased at 120°. That way you would always be able to reach Kerbin, provided that you have enough range to talk to either Kerbin or one of the two satellites. If you take this one more step farther, adding rings of relay satellites orbiting the sun would give you 99% coverage of the whole solar system, but then of course that's leaving the minimalistic, easy approach of your tutorial.

Best regards,

Breizhad

[Ohm is Futile]

From what I got from a quick read, I think nobody mentioned that relay antennas are combinable. The way I understood that is that extra antennas may improve the quality of your signal and maybe range (although I wouldn't assume that you just add all the values, probably are diminishing returns...)

 

So for your Jool and further out problems, stacking antennas may help... Furthermore, I am pretty sure the patch notes state that you do not necessarily need a connection to the KSC, but rather a connection to a vehicle with a command pod and a pilot. So, for example, you could send a "mothership" to any system with large antennas, a command pod and a pilot and simply relay to that ship to control probes within that planet's SOI.

[JAFO]

26 minutes ago, Ohm is Futile said:

From what I got from a quick read, I think nobody mentioned that relay antennas are combinable. The way I understood that is that extra antennas may improve the quality of your signal and maybe range (although I wouldn't assume that you just add all the values, probably are diminishing returns...)

This came under considerable discussion during the pre-release testing of 1.2. Yes, they do stack, and yes, there are diminishing returns. As I recall, if you stack sufficient numbers of antennae, you will get closer and closer to doubling the base range.

[IncongruousGoat]

8 hours ago, Breizhad said:

For the sake of argument I'd like to make a counter-point: AFAIK there are relay stations on earth (IRL) to talk to spacecraft, but the communication between those stations is handled via satellites. (Or was handled until the advent of high bandwith landlines) So in the game you should be forced to launch such satellites into orbit before you're able to use the extra ground stations. Or am I mistaken?

Here's a counter-counter-argument: We've had trans- and inter-continental communication via wired connection for going on a century and a half now, ever since the days of long-range telegraph networks. You don't need a satellite to achieve long-distance communication-you just need the satellite to transmit from an arbitrary location to an arbitrary location-the which is not necessary, since those relay stations aren't exactly going anywhere. You shouldn't need high-bandwidth communication for a satellite, because all you're sending are attitudes and burn times, and all the satellite is sending back is its telemetry. You're tossing numbers back and forth, not sending anything so complicated as, say, audio or video.

Of course, if I'm wrong, anyone feel free to correct me. I'm no telecommunications expert.

[Poodmund]

20 hours ago, Ohm is Futile said:

*snip*

20 hours ago, JAFO said:

*snip

Please note that I have made quite an extensive write up on this on the CommNet Wiki page, you may want to check it out for further reference: http://wiki.kerbalspaceprogram.com/wiki/CommNet

[JAFO]

2 hours ago, Poodmund said:

Please note that I have made quite an extensive write up on this on the CommNet Wiki page, you may want to check it out for further reference: http://wiki.kerbalspaceprogram.com/wiki/CommNet

Nice work! Very much appreciated. Thanks!

[Ohm is Futile]

@Poodmund outstanding work! So, if I understood all that correctly, in order to get 100% signal strength when using two vessels with one of the same antenna, you would have to stay within half the maximum range? Or if we look at the table provided on the wiki, half the listed ranges?

Taking this into account, in stock KSP the strongest relay you would ever need to always have 100% signal strength would require four RA-100s to relay from Eeloo to a DSN3 or another relay in Kerbin's SOI using four RA-100s?

EDIT: Hmm, using your spreadsheet seems to indicate otherwise, although I cannot figure out why...

Edited December 22, 2016 by Ohm is Futile

[Poodmund]

Not quite, even with the DSN3 and a craft with 11 RA-100 Relay Antennas, you'll still only get 75% Signal Strength at Eeloo's (rough) max distance of 127Gm.

i.e. DSN3 Power = 250,000,000,000

Craft Power = 100,000,000,000 * 11^(0.75) = 604,010,535,454 (This is a very simple calculation as the craft is using all the same antennas)

Max Range of Comm Link = SQRT ( 250E+09 * 604E+09 ) = 388,590,573,565m

Ratio of distance we want to communicate from over the maximum link distance possible = 1 - ( 127 / 388.6 ) = 0.67

So from this we can say that the vessel at 127Gm from Kerbin is around 67% of the way between the DSN Station on Kerbin and the max communicable distance.

As KSP calculates in-game signal strength by taking this ratio and applying it through a Bezier function, being y = ( 3 - 2 * x ) * x^2, we get the following in-game Signal Strength.

y = ( 3 - ( 2 * 0.67 ) ) * ( 0.67 ^ 2 ) 

y = 0.745 or 75%

As you can see it takes a bit of work.

 

Edited December 22, 2016 by Poodmund

[Ohm is Futile]

You can tell I'm bad at math since I assumed 2 antennas of the same strength would have 100% signal to each other at half their maximum ranges, but I made it easy on myself by using the 2Gm antennas, which made for easy calculations but wrong assumptions. Doing the math correctly did yield the same results as the spreadsheet...

Turns out my original idea of using a station with a pilot closer to the desired celestial body would be simpler and I'm glad I was right because I felt it would be way too easy if all you needed were four RA-100s to connect from Kerbin to anywhere with 100% signal. Although that doesn't fix the problem of transmitting the science if that was anyone's objective.

Also, why are you only considering Kerbin's 250Gm DSN 3? If you're going to send 11 RA-100s to Eeloo, wouldn't you assume you would at least have something more powerful than the DSN 3 near Kerbin to relay the signal near Kerbin? Or does it get even more complicated with more hops?

[Poodmund]

8 hours ago, Ohm is Futile said:

Also, why are you only considering Kerbin's 250Gm DSN 3? If you're going to send 11 RA-100s to Eeloo, wouldn't you assume you would at least have something more powerful than the DSN 3 near Kerbin to relay the signal near Kerbin? Or does it get even more complicated with more hops?

If a high signal strength is your aim for Eeloo comma then yes, a high powered relay satellite in Kerbin's orbit (operating at near 100% signal strength) would be preferable as a connection link due to its power being probably much higher than the DSN3's power. I just used the DSN3 as the example as that's what you had used as a reference in your post. 

However, there are issues with this and how KSP handles links. I'm fairly certain that if you put the relay in Kerbin's orbit, the satellite at Eeloo would still disregard it and want to talk directly with the DSN. This is due to the pathing limitations within CommNet and how it acts. It seems to prefer to always talk directly with a DSN station if possible, even at a lower signal strength, to avoid infinite looping situations.

Where Science transmission is concerned multiple hops are not an issue. The final Science gain is the product of the signal strength at each hop, i.e. a link to a low Eeloo relay from Eeloo's surface is 50% and then the link back to the DSN is 50%. Any Science transmitted will yield a net 25% return. 

To get around these issues with CommNet's pathing and potentially losing Science yield, I would recommend using DMagic's Science Relay mod where you can force to move your Science between specified crafts to route it back to the DSN to avoid any signal loss.

I hope this helps explain things a bit better.

 

[Emil Albert]

I don't know why you build so many satellites. I just started my network with two kerbosynchronous satellites, and additional ground stations turned off. The first satellite is right over KSC, the other one 90 degrees ahead in orbit. This should cover everything, beside the spots right behind the moons. And a relay in Duna orbit and one around Eve should cover these too, beside in the rare cases when Kerbol gets in the way at the same time. This should already pretty much cover the whole system.

Edited December 29, 2016 by Emil Albert

[MaxwellsDemon]

Getting my head around this...

I'm (finally) getting to the point in my 1.2(2) campaign where commo range is starting to become a significant factor.  I had misunderstood how quickly the smaller antennas drop off and thought I was fine, but I have two probes halfway to Eve and they're already in a 'limited probe control' situation.  I did some intensive R&D and worked up to the first fixed dish antenna (the probes each have one of the extendable dishes [HG-5] alongside a basic Communutron [16]) and scurried to put up a trio of keostationary relay satellites, only to find that A) it didn't solve the problem and B) coming here and finding this thread, it appears the keostationary project was a waste of time (although I don't regret doing it, because the missions themselves came off rather neatly and I was able to decommission a hodgepodge of older non-dedicated satellites).

My current understanding (thanks for the info, Geschosskopf et. al.) is that the best possible scenario is a big antenna on both ends of the line.  But, given a too-small antenna on one side (Eve-bound), can a bigger antenna on the home side compensate?  Or-- two (or more?) of the bigger ones on one relay satellite near Kerbin?  Or are my Eve probes headed for lonely oblivion a la Phobos and Mars Observer?

 

ETA:  I believe I didn't tweak the default settings, other than to set it to interfere with commo during reentry and to make the probe control dependent upon a commo link.  Running several mods, principally parts mods, in the stock system.  My Tracking Station is fully upgraded.

ETA2:  The next thing I am going to try is the pair of relays in eccentric polar orbits, as noted in the original post (I'd come up with the polar orbit idea independently, but the eccentric orbit is a good call-out).

Edited March 13, 2017 by MaxwellsDemon
correction

[mudkest]

4 ra-15 relays on a satalite *should*  be enough to get a path up to a single hg-5 dish located at eve. though very weak signal if eve-kerbin is at max distance.

a single ra-100 should give better coverage.

if you upgraded your trackingstation to lvl 2(or better, 3) it should also be strong enough to reach your sattalite. Off course if you have extra ground stations disabled then ksc needs to be in view, so to speak.

 

helpfull tool on following topic for figuring out what dish to bring

 

[MaxwellsDemon]

Gene Kerman sadly announced the official loss of the first two probes to Eve, but confirmed that the launches yesterday were two new Eve probes with significantly upgraded communications capabilities.

[HebaruSan]

I'm finally catching up on this mechanic, better late than never. Thanks for the helpful intro.

I have two important probes in LKO waiting for the Duna window, each with an RA-2 (2G signal strength), and my tracking station is level 3 (250G signal strength). I realized too late that those probes will probably lose signal before their capture burns (sqrt(2G*250G)=22G, Duna=7G–33G); I guess I assumed that career mode would take care of the CommNet pacing for me as long as I used my best antennae. Now I'm trying to figure out how to salvage the situation. I just unlocked the RA-15 (15G signal strength, sqrt(15G*250G)=61G). Several questions:

1. Am I correct that my RA-2's will fail to connect a good portion of the time at Duna?
2. Am I correct that an RA-15 will successfully connect at Duna?
3. Will a probe with an RA-15 at Duna be able to provide connectivity for other probes with RA-2's?
4. Is it sufficient to have just a relay antenna on a relay sat? Does it need a direct one as well?
5. What is the point of the non-relay antennae? When would you use them?

[Spricigo]

On 08/03/2018 at 8:40 PM, HebaruSan said:

better late than never.

I hope so. Since took some time for answers to your questions. Maybe you found it somewhere elsewhere, but in any case:

1. and 2. Correct in both conclusions.

4. The Relay antenna can do everything a Direct antenna can do.

5.Direct antennas are smaller, lighter, cheaper and require less power(to transmit science) than Relay Antennas of the same ratting.

 

 

 

 

 

[KerbMav]

 

Quote

 

Direct Antennae

• All the old stock antennae and the new dipole
• Can ONLY link to KSC, other ground antennae on Kerbin, or relay antennae on other ships.
• Can NOT link to direct antennae on other ships.

Relay Antennae

• All the new ones (except the dipole) added in 1.2
• Can link to ANYTHING:  KSC, other Kerbin ground antennae, relay antennae on other ships, and direct antennae on other ships.

 

THIS cannot be said enough - with Comnet regular antennas do not bounce signals, only relay antennas do.

It is kinda mentioned in the KSPedia in the game, but only in the positive that relay antennas do this, not in the negative that normal antennas do not.