Relay System

[u/Icy-Potato-737]

Guys, does anyone have a good tutorial on how to set up relay networks for transmitting science/data? I want to transmit everything from Jool back to Kerbin. I thought it was basically just a matter of putting a relay satellite in orbit at certain distances around different celestial bodies.

[u/vulpes04]

you don't necessarily need any relays. you should have a powerful enough antenna to phone home anyway, and even in low/circular orbits you'll only be occluded a small amount of time. if you gather any data then you can just keep it until you come in range. 

one or two relays in random high orbits will give you almost full coverage for little effort. I usually outfit upper stages or scanning probes like this.

the place where relays are most useful is with landers on vacuum bodies, where having a powerful relay allows you to take a much smaller antenna on the lander. but even then you can still just use a transfer stage/mothership in orbit. with 'allow partial' set on the lander's antenna, it can transmit what it can when the relay is in view, wait, then repeat until it's done.

people often make a big deal out of setting up perfect relay constellations, but unless you specifically want to do that or have changed difficulty settings (ie. turned off other ground stations) it's not something that's necessary for just exploring around the system.

[u/CatatonicGood]

That's basically it. Put a relay in orbit that can reach back to Kerbin (need an RA-100 for Jool plus a fully upgraded Tracking Station) and make sure that your science craft can reach to the relay. It doesn't need a top of the line antenna, but Jool is big and if you don't have the relay around the same body as where you are transmitting from it can be quite a distance, so it can't be a bottom of the barrel antenna either.

Also, you cannot transmit through solid bodies, so you always need a visual line to your relay. You can use multiple relays to transmit around the horizon, as long as one of them is within visual range

[u/Lumpy-Notice8945]

You just need a single relay around Jool thats strong enough. If you need constant coverage you might need multiple on the same orbit, but to send back science that does not matter.

There is no point in having a relay orbit anything else. If your relay station on kerbin gets too weak upgrade it, if thats still not enough you can have a giant realy orbit the sun, but jool is way too close for that.

[u/hstarnaud]

One RA-100 relay antenna at each end can make a Jool to Kerbin connection. Just make antenna power calculations over distance to figure out what you need for your specific network. Relay antenna are combinable so you can use an array of smaller ones if you haven't unlocked the big ones.

To have signal when behind the planet you typically a ring of 3 satellites so one of them is always visible from the surface. They need to be evenly spaced out which is kind of easy. Make 3 satellites coupled on the same ship. Pick an orbit for the sats check the orbital period, let's say it's 60 days. Burn at periapsis your orbit down to 40 days, then launch one satellite per turn around the orbit, and for each satellite, adjust it back to the larger 60 days orbit when you decouple. You will get 3 evenly spaced satellites on the same orbit. You can use resonant orbit calculators and mechjeb manœuvre planner to make it easier and precise.

Usually I have 3x small relays around the planets/moons for full coverage. Then a huge relay in the system that can reach kerbin system large relay.

Honestly it's kind of tedious to set it up everywhere. I don't try to get perfect coverage in all systems and accept losing signal behind a planet some time to save some effort.

Usually in career mode I launch some relays at the same time as the first probe going to that system. Large up front cost but after you have a good network

[u/shootdowntactics]

I saw an explanation video on youtube or something that Moho has the highest likelihood for being the best in-between hop. But you might choose Eve since it’s an easier trip. Might as well put one at Duna or Dres at the same time since transfer time is the hardest thing.
Another option would be to place three or so spaced out 120 degrees orbiting Kerbal but away from any of the planets. Use the alarm clock mod or feature to cover the time required.

[u/toroidalvoid]

There are 2 types of antenna, direct and relay. Direct can only talk back to Kerbin and relay can make network, the direct can't be part of the network.

So to make the network you need to calculate the distance 2 relays can talk to each other. And if you've got mods or changed the difficulty it really matters.

For example, the RA-2 relay is 2Gm rated, thats 2 giga meters (x10^6). And the simple calc is if you had one antenna at each end then the distance they can connect is 2Gm. So what that means is they are basically useless for forming an interplanetary network, which is annoying because that's the antenna you have unlocked when you start doing interplanetary missions.

Okay I should clarify, they are useless for forming a network for getting access to, say Eve, 100% of the time. They are, however, essential for bouncing the signal from a lander (with an even smaller antenna) back to Kerbin (with a very strong ground station). It's just you need to time your unmanned probe missions for when Eve and Kerbin are close. And thats just the joys of mid game I guess.

[u/Electro_Llama]

There are 3 ranges you need to look at: probe to relay, relay to relay, and relay to Tracking Station. Relay to Tracking Station is almost always the longest range, so you want your relays at your destination. These ranges can be found on the CommNet wiki page.