Help with my Relay CommSat Probe? When Too Much is Not Enough

[scottadges]

Hello fellow KSP folks! I'm hoping the kind souls in this community can help me avoid actual maths as I plan to launch a mega-relay network in the Kerbol system.

Here is my (probably well-overbuilt) CommNet relay / direct communications probe:

My main question:

How much signal power will I realistically be getting? Can I guess-timate this without actually doing the math work here or here. 

Specs:

• 9x RA-100 = 100G x 9 = 900G
• 4x Communotron 88-88 (Tweakscaled to 220% because, aesthetics) = 484G x 4 = 1,936G
• 1x RC-01S = 5K

My goal is to have six of these orbiting around Kerbol at a decent distance to cover the entire solar system. I'm playing with the Outer Planets mod, so I've got to get signal all the way out to Neidon and maybe even Plock.

Appreciate all your help!

(Also moderators, please if this question/topic is not in the correct forum, please go ahead and put this in the right place.) 

 

Edited November 15, 2020 by scottadges

[AHHans]

4 hours ago, scottadges said:

Can I guess-timate this without actually doing the math work here or here. 

Not really. You should at least read the wiki page about CommNet! (Your first link.)

I don't know the Outer Planets mod, what is the maximum distance that you need to cover?

[scottadges]

1 minute ago, AHHans said:

Not really. You should at least read the wiki page about CommNet! (Your first link.)

Thanks, I have read through the CommNet wiki page a few times over the years and usually get to the "square root of something" before I start glazing over and usually just slap more antennas on the thing. (Maths were never my strong suit)

But this time, I'm hoping to get a little more specific with what I need to launch in my Career game. 

Appreciate your reply!

[AHHans]

1 hour ago, scottadges said:

But this time, I'm hoping to get a little more specific with what I need to launch in my Career game.

Well, to be more specific, I would need to know what you actually need. So what's the maximum distance, and what antenna do you plan to put on the other side?

[Fraktal]

If you don't want to do the math yourself, consider getting the Antenna Helper mod. It does all the antenna stacking calculations for you in the VAB, can calculate coverage and signal strength between Kerbin and any other planet while still in the VAB and once you launch one of these satellites, it can graphically render the antenna's reception on the map view and the Tracking Station so that you can see what kind of signal strength you can expect at what distance with which craft.

[bewing]

The direct antennas don't help at all. They don't mix with relay antennas, and cannot bounce signals. They only provide control for the current craft.

So all you have is 9 100G relays. That gets you a relay antenna signal power for the satellite of 100G * 9 ^ .75 = 520 G.

There is a "range modifier" in your settings that gets multiplied into the range calculation, which is the square root thing, which depends on the antenna of the probe craft.

[Snark]

9 hours ago, scottadges said:

How much signal power will I realistically be getting? Can I guess-timate this without actually doing the math work here or here. 

Specs:

• 9x RA-100 = 100G x 9 = 900G
• 4x Communotron 88-88 (Tweakscaled to 220% because, aesthetics) = 484G x 4 = 1,936G
• 1x RC-01S = 5K

My goal is to have six of these orbiting around Kerbol at a decent distance to cover the entire solar system. I'm playing with the Outer Planets mod, so I've got to get signal all the way out to Neidon and maybe even Plock.

As @bewing correctly points out above, the Communotrons won't help you at all for your relay power, since they're direct antennas.  All that matters is the actual relay antennas.

RA-100, like most antennas, doesn't stack linearly.  It's an exponential fall-off.  The actual antenna power is:  take the number of antennas, raise that to the 0.75 power, and multiply that by the power of one antenna.  You have 9 of them, so 9 ^ 0,75 = ~5.2.  Therefore, as bewing points out,

1 hour ago, bewing said:

So all you have is 9 100G relays. That gets you a relay antenna signal power for the satellite of 100G * 9 ^ .75 = 520 G.

At its outermost orbit, Plock is beyond that (689G), so this comsat won't reach that far as a relay.

The issue that you're running into is that the stock antennas were designed to work with the stock solar system.  If you're working with solar systems that are much bigger than the stock one, this has the potential to cause problems.  There are various ways to deal with this.  One way is to use some combination of multiple-hop relays with spamming lots of RA-100.  Another way is to use a mod.

If you're open to the idea of using mods, here's a mod with a giant 1000G antenna, specifically designed for playing in larger-scale modded solar systems.  It includes a compatibility patch for Outer Planets:

 

[scottadges]

6 hours ago, Fraktal said:

If you don't want to do the math yourself, consider getting the Antenna Helper mod

Oooh *furiously typing in CKAN and Spacedock* I'll take a look at that one!

5 hours ago, Snark said:

If you're open to the idea of using mods

I am definitely open to mods 

Thanks for the suggestion, I'll look at that one. Also thank you for mentioning Plock is ~700G at the edge of the system. That's something I was trying to figure out.

[scottadges]

10 hours ago, AHHans said:

what is the maximum distance that you need to cover?

With the Outer Planets mod, I need to get out to Plock - which requires 689G to reach out there (as @Snark graciously pointed out).

[scottadges]

Thought I'd post the updated version of my CommSat relay probe based on the calcs and suggestions from the fine group of folks on this thread.

The JX2 Antenna looks phenomenal on this bad boy. Since all my relays all have a mechanical/industrial aesthetic, this fits in perfectly along with the excellent gold accents.

Looking forward to launching 6 of these into Kerbol-centric orbit!

Edited November 15, 2020 by scottadges

[AHHans]

12 hours ago, scottadges said:

With the Outer Planets mod, I need to get out to Plock - which requires 689G to reach out there

Well, as @Snark already wrote, the short answer is that if you want to do that in one hop, then you want modded antennas. Even the fully upgraded (stock) tracking station cannot talk to itself over that distance.

To have a satellite that could talk to (a copy of) itself at that distance it would need 14 RA-100 antennas on it. A satellite that could talk to a single RA-100 or Communotron 88-88 over that distance would need a strength of 4748G or 172 RA-100 antennas.
(Can be done, but I question if it should be done.)

[Snark]

17 hours ago, scottadges said:

The JX2 Antenna looks phenomenal on this bad boy.

Glad you like it. 

...Out of curiosity, is there any particular reason you've got that 88-88 stuck on there, as well?  It's not really doing anything.  Is it just for looks?

[jimmymcgoochie]

If you're going down the mod route, there are a few more options open to you to make long-range communications practical:

• Level 4 Tracking Station- I believe there's a variant of OPM that includes a further upgrade to the tracking station which boosts its range even further;
• Extended Antenna Progression- while they just look like bigger 88-88 antennas, they function as increasingly powerful relays- the biggest have ranges into the light years and their power consumption when transmitting is very low for their power, but they're very big and very heavy;
• Near Future Exploration and its signal reflection system- combining a fairly small transmitter part with a big signal reflector can drastically improve its range, sometimes by a few terametres (billions of km!) without adding a huge amount of weight. They're big but look great, and NFX ties in nicely with the other Near Future mods as well as Restock- hardly surprising as they're all made by the same person so share the same art style-  plus it contains other useful probe-related parts.
• Or just crank up the DSN and antenna power in the settings for your save, it's not really cheating if you're using a larger system like OPM

[Spricigo]

19 hours ago, AHHans said:

To have a satellite that could talk to (a copy of) itself at that distance it would need 14 RA-100 antennas on it. A satellite that could talk to a single RA-100 or Communotron 88-88 over that distance would need a strength of 4748G or 172 RA-100 antennas.
(Can be done, but I question if it should be done.)

Personally, I have a hard time to decide which of those is a less practical "solution".

[scottadges]

On 11/16/2020 at 10:56 AM, Snark said:

It's not really doing anything.  Is it just for looks?

Mostly.   The whole thing felt like it needed something at the front/top.

Edited November 20, 2020 by scottadges