Clarification

[ansaman]

I am still confused about the intended combined antenna capabilities. Do "direct" antennas actually "stack?"  What about relay antennas?  I am working with a very limited tech and money capability in a career game and it is making a big difference.

[MR L A]

Yes, "direct" and "relay" (afaik on relay) antennas stack, but with diminishing returns i.e. 10 Communotron 16s will have better range than a single 16.. but it wont even be close to 10x range. Realistically, you want one direct antenna with the maximum possible range you have access to, to keep costs down. If range is turning out to be the main problem, you could do with creating a relay, and bouncing the signal around to your target, though this is inherently expensive (not as expensive as catastrophic mission failure due to lack of probe control, mind).

It's also worth checking to see if you have probe control enabled in difficulty settings or not. It means you will retain some control over your probes with 0 signal, but only max or zero throttle etc

Finally, if you're that strapped for cash in career mode, you could do with doing a few contract missions for easy wonga  

[Snark]

Moving to Gameplay Questions.

4 hours ago, ansaman said:

Do "direct" antennas actually "stack?"

• In general:  Depends on the antenna.
• Specifically:  All the "direct" stock antennas stack, except the Communotron-16S.

4 hours ago, ansaman said:

What about relay antennas?

• In general:  Depends on the antenna.
• Specifically:  All the "relay" stock antennas stack.

Note:  "Stacking" isn't just a binary yes-or-no.  There's also the question of how well do they stack.  Specifically, there's this thing called a "combinability exponent" that determines how powerful the combination is-- in general, it's not linear.  The default combinability exponent for any part that doesn't otherwise specify is 0.75, meaning that if you have N antennas, their combined power will be N^0.75.  (The actual formula's a bit more complicated than that, to allow for possibly having different kinds of antennas with different powers.  But if all the antennas involved have the same power as each other, it boils down to that.)

All the stackable stock antennas have a combinability exponent of 0.75, except for the Communotron-16.  That one has an exponent of 1, meaning that it stacks better-- linearly, in fact.  If you have 4 Communotron-16 antennas on a craft, they'll have 4 times the power of a single one.

So, to summarize:

• Communotron-16S does not stack.
• Communotron-16 stacks linearly.
• Everything else stacks with a combinability exponent of 0.75.

2 hours ago, MR L A said:

stack, but with diminishing returns  i.e. 10 Communotron 16s will have better range than a single 16..

You're generally correct, as described above... except you got unlucky and picked the worst possible example, since you mentioned the one single stackable stock antenna that actually doesn't have diminishing returns.   

[ansaman]

Thanks so much for this complete and useful answer !

[Spricigo]

In case of doubt you may check there.  

A details that seems to cause confusion often:

All combinable antennas contribute to your active vessel antenna power.  No matter if talk direct to a ground station or through relays. But only relay antennas are considered for the (not-active)  relay satellites. 

Example: 

We have a lvl2 tracking station (ground stations power 50Gm) and two vessels: Audacious and Brave.

Audacious have a DTS-M1 and a RA-2 while Brave have  two RA-2. 

Both craft will have a direct antenna power of 3.36Gm, however the relay antenna power will be 2G to audacious and 3.36G for Brave. 

Both vessels can talk directly to Kerbin up to 12.9Gm away.  

Audacious can reach KSC using Brave as relay if both are 3.36Gm away and Brave is less than 12.9Gm away from Kerbin. This may extend the range up to 15. 25Gm

Brave  it can only reach Audacious (acting as relay) up to 2.59Gm away and brave can only relay to a ground station up to 10Gm away. Being usefull only in case Brave don't have Line of Sight. 

[MR L A]

20 hours ago, Snark said:

You're generally correct, as described above... except you got unlucky and picked the worst possible example, since you mentioned the one single stackable stock antenna that actually doesn't have diminishing returns.   

Well bugger. Haha!