Difference between revisions of "CommNet"

From Kerbal Space Program Wiki
Jump to: navigation, search
(Relays)
(difficulty settings)
 
(17 intermediate revisions by 13 users not shown)
Line 1: Line 1:
'''CommNet''' is a relay and control communication system implemented first in KSP 1.2 pre-release. Probes now have limited attitude and thrust control if they are not linked back to Kerbin or a control point via a relay [[antenna]]. <ref name="commnet">https://docs.google.com/document/d/1Tu3KnB1alOMn_VXqF31BPDbAu24HdHLiYP2V1I6b6pU/edit</ref> Antennae have limited range from which control and transmission of science data is possible.
+
'''CommNet''' is a relay and control communication system implemented first in KSP 1.2 pre-release. With CommNet enabled (as a difficulty setting), antennae have limited range from which control and transmission of science data is possible. Vessels without a [[Pilot]] require a link to a control source for full control (valid control sources are a vessel with an operational [[Probe_Control_Point|Probe Control Point]], or more commonly the Deep Space Network on [[Kerbin]]). Locations may be linked either through a direct connection or indirectly via one or more relays.  
  
 +
The following table lists the maximum range for vessels with a single antenna signaling the Deep Space Network:
 
{| class="wikitable"
 
{| class="wikitable"
 
! colspan="2" rowspan="2" | '''Antenna Type'''
 
! colspan="2" rowspan="2" | '''Antenna Type'''
Line 7: Line 8:
 
! '''1''' (2G) !! '''2''' (50G) !! '''3''' (250G)
 
! '''1''' (2G) !! '''2''' (50G) !! '''3''' (250G)
 
|-
 
|-
| <center>'''5k'''</center> || <center>'''Command pods (Built-in)'''</center> || <center>3.16Mm (25% way to Mun)</center> || <center>15.81Mm (Mun)</center> || <center>35.36Mm (75% way to Minmus)</center>  
+
| <center>'''5k'''</center> || <center>'''Command pods (Built-in)'''</center>
 +
| <center>3.16Mm (25% way to Mun)</center>
 +
| <center>15.81Mm (Mun)</center>
 +
| <center>35.36Mm (75% way to Minmus)</center>  
 
|-
 
|-
| <center>'''500k'''</center> || <center>'''[[Communotron 16]] / [[Communotron 16-S|16-S]]'''</center> || <center>31.62Mm (67% way to Minmus)</center> || <center>158.11Mm (Kerbin SOI)</center> || <center>353.55Mm (Kerbin SOI)</center>
+
| <center>'''500k'''</center> || <center>'''[[Communotron 16]] / [[Communotron 16-S|16-S]]'''</center>
 +
| <center>31.62Mm (67% way to Minmus)</center>
 +
| <center>158.11Mm (Kerbin SOI)</center>
 +
| <center>353.55Mm (Kerbin SOI)</center>
 
|-
 
|-
| <center>'''5M'''</center> || <center>'''[[HG-5 High Gain Antenna|HG-5 High Gain]]'''</center> || <center>100Mm (Minmus)</center> || <center>500Mm (Interplanetary around Kerbin)</center> || <center>1.12Gm (Interplanetary around Kerbin)</center>
+
| <center>'''5M'''</center> || <center>'''[[HG-5 High Gain Antenna|HG-5 High Gain]]'''</center>
 +
| <center>100Mm (Minmus)</center>
 +
| <center>500Mm (Interplanetary around Kerbin)</center>
 +
| <center>1.12Gm (Interplanetary around Kerbin)</center>
 
|-
 
|-
| <center>'''2G'''</center> || <center>'''[[Communotron DTS-M1|DTS-M1]] / [[RA-2 Relay Antenna|RA-2]]'''</center> || <center>2Gm (Interplanetary around Kerbin)</center> || <center>10Gm (Moho, Eve & Duna when close)</center> || <center>22.36Gm (Moho always, Eve, Duna & Dres (barely) if close)</center>
+
| <center>'''2G'''</center> || <center>'''[[Communotron DTS-M1|DTS-M1]] / [[RA-2 Relay Antenna|RA-2]]'''</center>
 +
| <center>2Gm (Interplanetary around Kerbin)</center>
 +
| <center>10Gm (Moho, Eve & Duna when close)</center>
 +
| <center>22.36Gm (Moho always, Eve, Duna & Dres (barely) if close)</center>
 
|-
 
|-
| <center>'''15G'''</center> || <center>'''[[Communotron HG-55|HG-55]] / [[RA-15 Relay Antenna|RA-15]]'''</center> || <center>5.48Gm (Eve when close)</center> || <center>27.39Gm (Always Moho & Eve, Duna & Dres if close)</center> || <center>61.24Gm (Dres, Jool & Eeloo if close, other planets always)</center>
+
| <center>'''15G'''</center> || <center>'''[[Communotron HG-55|HG-55]] / [[RA-15 Relay Antenna|RA-15]]'''</center>
 +
| <center>5.48Gm (Eve when close)</center>
 +
| <center>27.39Gm (Always Moho & Eve, Duna & Dres if close)</center>
 +
| <center>61.24Gm (Dres, Jool & Eeloo if close, other planets always)</center>
 
|-
 
|-
| <center>'''100G'''</center> || <center>'''[[Communotron 88-88]] / [[RA-100 Relay Antenna|RA-100]]'''</center> || <center>14.14Gm (Moho, Eve & Duna when close)</center> || <center>70.71Gm (Jool & Eeloo if close, other planets always)</center> || <center>158.11Gm (all bodies always)</center>
+
| <center>'''100G'''</center> || <center>'''[[Communotron 88-88]] / [[RA-100 Relay Antenna|RA-100]]'''</center>
 +
| <center>14.14Gm (Moho, Eve & Duna when close)</center>
 +
| <center>70.71Gm (Jool & Eeloo if close, other planets always)</center>
 +
| <center>158.11Gm (all bodies always)</center>
 
|}
 
|}
  
Please Note: The above table presumes only 1 antenna/relay is used on a vessel signalling back to Kerbin's DSN.
+
== Range calculation ==
<br /><br />
+
Individual vessels do not have a fixed maximum range: whether a connection is possible between two vessels that are a given distance apart depends on the transmission strength of the vessels at ''both'' ends of the connection. Each antenna has a "power rating", measured as a unitless number, which contributes to the overall power rating of the vessel it is attached to. A connection can be established between two vessels when the geometric mean of their power ratings is greater than their separation as measured in meters.
 +
This is calculated as follows:
 +
{{Formula
 +
|math code = <math> Range = \sqrt{Vessel_1 \times Vessel_2} </math>
 +
|where =
 +
*<math>Range</math> is the maximum distance in meters at which two vessels can connect with each other.
 +
*<math>Vessel_1</math> and <math>Vessel_2</math> are the power ratings for the vessels that are attempting to connect to each other.
 +
}}
 +
Power ratings for antennae range from '''5k''' for the integrated antenna available in every [[Command module]], to '''100G''' for the largest dishes. Kerbin's Deep Space Network can be treated as a vessel with a rating of '''2G'''/'''50G'''/'''250G''' (depending on the level of the [[Tracking Station]]) for the purposes of calculating range.
  
== Range Calculation ==
+
=== Combining antennas ===
Each antenna has a "power rating" (measured in unitless number). It ranges from '''5k''' for the integrated Command-Module antenna available in every spacecraft, to '''100G''' for the largest dishes.
+
When a craft has multiple, combinable antennas, the antenna's power ratings stack in a way that provides diminishing returns using the following formula:
A connection can be established between two stations (craft to ground, or craft to relay) when the square root of the product of the strength ratings is greater than the distance between the two objects.
 
When a craft has multiple, combinable antennas, the antenna's power ratings stack in a way that provides a diminished return using the following formula:
 
  
* Vessel Antenna Power = Strongest Antenna Power * ( Sum of Antenna's Powers / Strongest Antenna Power ) ^ ( Average Weighted Combinability Exponent for Vessel )
+
<math> \text{Vessel Power} = \text{Strongest Antenna Power} \times \left ( \tfrac{\text{Sum of Antenna Powers}}{\text{Strongest Antenna Power}} \right ) ^ \text{Average Combinability Exponent} </math>
  
The range can then be calculated as stated above by taking the square root of the product of the two Antenna Strength ratings
+
The vessel's Average Combinability Exponent is the average of the combinability exponent values of all antennas on the vessel, where each antenna is weighted proportionally to its respective power rating. Note that all antennas and relays have a combinability exponent value of 0.75 except for the Communotron 16 and the Communotron 16S, with values of 1.0 and 0.0 respectively. This means that the Average Combinability Exponent will always be 0.75 for a vessel containing neither of these antennae. For vessels with a Communotron 16 or 16S, the Average Combinability Exponent is calculated:
  
* Range = SQRT ( Antenna Strength 1 * Antenna Strength 2 )
+
{{Formula
 +
|math code = <math>\text{Average Combinability Exponent} = \frac{P_1 C_1 + P_2 C_2 + \cdots + P_n C_n}{P_1 + P_2 + \cdots + P_n} </math>
 +
|where =
 +
*<math>\{P_1, P_2, \dots , P_n\}</math> are the power ratings of each antenna.
 +
*<math>\{C_1, C_2, \dots , C_n\}</math> are the combinability values of each respective antenna.
 +
}}
 +
For example, a vessel with a Communotron 88-88 (100G power, 0.75 combinability) and also a Communotron 16 (500k power, 1.00 combinability) would have the following as its Average Combinability Exponent:
  
The Average Weighted Combinability Exponent for the Vessel can be thought of as the average of the sum of the combinability exponents of all combinable antennas on the vessel when weighted proportionally against their respective power level. This can be shown in the following way:
+
<math> \frac{(100 \times 10^9) \times  0.75  + (500 \times  10^3) \times  1.00}{(100 \times  10^9) + (500 \times  10^3)} = 0.75000125 </math>
  
* SUM (( Antenna 'n' Power * Antenna 'n' Exponent ) : ( Antenna 'n+1' Power * Antenna 'n+1' Exponent )) / SUM ( Antenna 'n' Power ) : ( Antenna 'n+1' Power )
+
Antennae combinability exponent values can be found under "antennaCombinableExponent" in the part configuration files. If the value is missing, the default value of 0.75 is used.
 +
== Signal strength ==
  
i.e. A vessel with a Comm 88-88 (100e9 @ 0.75) and also a Comm 16 (500e3 @ 1.00) would have the following:
+
The length of a communication link relative to its maximum range is represented by signal strength. Signal strength for a single-hop link starts at 100% at a distance of zero and decreases as distance increases, down to a signal strength of 0% at the maximum range of the link. The relationship is non-linear: the true value requires plotting the relative distance on a [[w:Cubic Hermite spline|Bezier curve]] with the keys '0 0 0 0' and '1 1 0 0'. This can be calculated as follows:
  
* (( 100e9 * 0.75 ) + ( 500e3 * 1.00 )) / ( 100e9 + 500e3 ) = 0.75000125 ... being the Weighted Average Combinability Exponent for the Vessel.
+
* Calculate the relative distance between the vessels (the result should be between 0.0 and 1.0): <math> 1 - \frac{\text{Distance From Link Point}}{\text{Maximum Range}} </math>
 +
* Substitute the result above into the Bezier curve equation (cubic derivation): <math>-2x^3 + 3x^2 </math> or <math> (3-2x)x^2</math>
  
Please Note: All Antennas and Relays have a Combinability Exponent value of 0.75 except for the Communotron 16 having a value of 1 and the Communotron 16S having a value of 0. These values can be found in the part config files.
+
The result is the signal strength of the link at the specified distance. Note that the above applies to a single-hop link: if the signal is being bounced through one or more relays, the signal strength is the product of the signal strengths of each link making up the path to the control point.
  
== Signal Strength ==
+
=== Example ===
 +
Calculating the Signal Strength between a Level 3 DSN Tracking Center and a probe around Jool at a distance of 73.4Gm from Kerbin with two Communotron 88-88 antennas:
  
To obtain your signal strength for a link at any given distance between the two points it is mostly the relative distance between the two points. The true calculation requires plotting the relative distance on a Bezier curve with they keys '0 0 0 0' and '1 1 0 0' to obtain the true Signal Strength. This can be calculated as follows:
+
* Max Power of Lvl 3 DSN connection: <math> 250\,000\,000\,000 </math>
  
* 1 - ( Distance away from 'Link Point' / Max Range of Antenna Link ) = 0 < x < 1 (as a fractional percentage)
+
* Max Power of Probe: <math> 100\,000\,000\,000 \times \left (\frac{200\,000\,000\,000}{100\,000\,000\,000}\right )^{0.75} = 168\,179\,283\,051 </math>
  
* Substitute the result above into the Bezier Curve equation (Cubic derivation) of y = -2x³ + 3x² = (3-2x)
+
* Max Range of Connection: <math>\sqrt{(2.5\times 10^{11})\times (1.68\times 10^{11})} = 205\,048\,337\,625 \text{m} </math>
  
This will give you the Signal Strength between the link at your specified distance.
+
* Relative distance between Link Points: <math> 1 - \frac{73.4}{205} = 0.642 </math>
  
=== Example ===
+
* Signal Strength: <math> (3-2\times 0.642)\times 0.642^2 = 0.707 = 71% </math>
Calculating the Signal Strength between a Level 3 DSN Tracking Center and a probe around Jool at a distance of 73.4Gm from Kerbin with two Communotron 88-88 antennas.
+
 
 +
Therefore the signal strength for this connection would be 71%.
  
* Max Power of Lvl 3 DSN connection: 250,000,000,000
+
== Connections through Relays ==
  
* Max Power of Probe: 100,000,000,000 * (200,000,000,000 / 100,000,000,000)^0.75 = 168,179,283,051
+
When considering the antenna power of your vessel, Direct Antennas and Relay Antennas combine to give you a 'Power' to calculate Signal Strength back to the KSC, however, if a different vessel is connecting through you to communicate with the KSC the Direct Antennas are disregarded in any calculations made.
  
* Max Range of Connection: SQRT( 2.5E11 * 1.68E11 ) = 205,048,337,625m
+
=== Example ===
 +
* A vessel with a Communotron 88-88 Direct Antenna and a RA-100 Relay Antenna orbiting around Eeloo at a distance of 105Gm from the KSC, with a Level 3 DSN, will connect back to the KSC with a Signal Strength of 48% as both antennas combine to give an increased antenna 'Power' for its own direct connection.
  
* Relative distance between Link Points: 1 - ( 73.4 / 205 ) = 0.642
+
* A vessel rendezvoused with the above craft with a measly Communotron 16 will have to communicate back to the KSC through the relay as its antenna is not strong enough to communicate with the KSC directly. As this small, probe craft will only consider the RA-100 Relay Antenna on the relay craft when calculating its connection back to the KSC, the power rating of the relay vessel drops and therefore the Signal Strength will drop to 26% (please note the calculations for these numbers have been obfuscated from the example for easy understanding of the concept).
  
* Signal Strength: y = (3-2x)x² = (3-2(0.642))*(0.642)² = 0.707 = 71%
+
Please keep the above in mind when creating relay vessels for you other craft to connect through in the depth of space.
  
Therefore the Signal Strength for this connection would be 71%.
+
== Effects of signal loss ==
 +
Depending on your difficulty settings, several effects occur when the CommNet signal is lost, either from the KSC or a probe control point. This could be due to either electricty loss, out of CommNet range, or an antenna destruction. There is also a setting where you can force the signal to blackout when entering a body's atmosphere too fast.
  
== Relays ==
+
SAS doesn't depend on the CommNet signal. It depends only on the ship's ability to use SAS (pilot or capable probe, kerbal XP or all probes have SAS settings).
  
When considering the antenna power of your vessel, Direct Antennas and Relay Antennas combine to give you a 'Power' to calculate Signal Strength back to the KSC, however, if a different vessel is connecting through you to communicate with the KSC the Direct Antennas are disregarded in any calculations made. For example:
+
=== Manned without a pilot ===
 +
You will lose the ability to create maneuver nodes, or delete existing ones
  
* A vessel with a Communotron 88-88 Direct Antenna and a RA-100 Relay Antenna orbiting around Eeloo at a distance of 1.05Gm from the KSC, with a Level 3 DSN, will connect back to the KSC with a Signal Strength of 48%.
+
=== Probe, require control unchecked ===
 +
Your probe will lose three capabilities : rotation control (roll, yaw, pitch), precise thrust control (only 0 or maximum), and the ability to create or remove maneuver nodes.
  
* A vessel rendezvoused with the above craft with a measly Communotron 16 will have to communicate back to the KSC through the relay as its antenna is not strong enough to communicate with the KSC directly. As this small, probe craft will only consider the RA-100 Relay Antenna on the relay craft when calculating its connection back to the KSC, the power rating of the relay vessel drops and therefore the Signal Strength will drop to 26% (please note the calculations for these numbers have been obfuscated from the example for easy understanding of the concept).
+
If your probe is capable of locking a maneuver axis through SAS, it is advised to create a maneuver node before transmission blackout (passing behind a body) to allow the ship to perform the maneuver.
  
Please keep the above in mind when creating relay vessels for you other craft to connect through in the depth of space.
+
=== Probe, require control checked ===
 +
You will completely lose control of your probe. Either wait for it to go back to a CommNet range, or send a ship with a probe control point capability to do general maneuvers (deploy solar panels, precise control,...).
  
 
== DSN Strength ==
 
== DSN Strength ==
Line 83: Line 123:
  
 
== Science Transmission ==
 
== Science Transmission ==
The same document from the KSP developers states that science returned via a relay satellite will have a bonus applied (some fraction of the difference between the recovery and transmission science potential). The exact amount of the bonus depends upon signal strength.
+
Signal strength has no bearing on transmitting [[Science|science]] directly to the KSC, but vessels transmitting  through a relay will gain a 40% bonus to the data transmitted (to a maximum of 100% value). For example, a Gravity Scan from low Jool orbit would give 90*0.4=35 Science if transmitted directly, but if bounced through a relay with an overall strength of 100% would give 90*0.4*1.4=50.4 Science. This bonus decreases non-linearly with signal strength.
The amount of available Science Points you can transmit back to the KSC depends on your Signal Strength and the total potential value of the experiment.
+
 
 +
== Difficulty Settings ==
 +
Activate CommNet = If unchecked, all ships have full control, antennas still work but are just used to check range.
  
Any experiments transmitted will be multiplied by the percentage of your connection, therefore an EVA Report high over the Mun (24 Science) at a Signal Strength of 68% would allow you to transmit a total of 16 Science points back to the KSC.
+
Required signal for control = Unchecked : probes have limited actions when out of range (full thrust only, SAS,...). Checked : probes will be uncontrollable until back in range.
  
== Difficulty Settings ==
+
Plasma blackout = If checked, a fast atmospheric re-entry might block the signal and put a probe in an uncontrollable state.
  
 
Range Modifier = The value of this slider is a multiplier value that is applied to the power levels of all Antenna and Relay parts.
 
Range Modifier = The value of this slider is a multiplier value that is applied to the power levels of all Antenna and Relay parts.
  
 
DSN Modifier = The value of this slider is a multiplier value that is applied to the power level of the DSN Network.
 
DSN Modifier = The value of this slider is a multiplier value that is applied to the power level of the DSN Network.
 +
 +
Allow additional ground stations = Adds antennae on the surface of Kerbin, or else only the KSC has an antenna and you must build your own Kerbin relay sat system.
  
 
== Tutorials, Calculators and Examples ==
 
== Tutorials, Calculators and Examples ==
Line 99: Line 143:
 
Example orbits for setting up a planetary network can be found at: [[Tutorial:Ideal Orbits for Communication Satellites]]
 
Example orbits for setting up a planetary network can be found at: [[Tutorial:Ideal Orbits for Communication Satellites]]
  
== References ==
+
One method of setting up a full-system network can be found at [[Tutorial:Setting up a CommNet system]].
<references />
 

Latest revision as of 21:26, 16 August 2019

CommNet is a relay and control communication system implemented first in KSP 1.2 pre-release. With CommNet enabled (as a difficulty setting), antennae have limited range from which control and transmission of science data is possible. Vessels without a Pilot require a link to a control source for full control (valid control sources are a vessel with an operational Probe Control Point, or more commonly the Deep Space Network on Kerbin). Locations may be linked either through a direct connection or indirectly via one or more relays.

The following table lists the maximum range for vessels with a single antenna signaling the Deep Space Network:

Antenna Type Tracking Station Level (Rating)
1 (2G) 2 (50G) 3 (250G)
5k
Command pods (Built-in)
3.16Mm (25% way to Mun)
15.81Mm (Mun)
35.36Mm (75% way to Minmus)
500k
Communotron 16 / 16-S
31.62Mm (67% way to Minmus)
158.11Mm (Kerbin SOI)
353.55Mm (Kerbin SOI)
5M
HG-5 High Gain
100Mm (Minmus)
500Mm (Interplanetary around Kerbin)
1.12Gm (Interplanetary around Kerbin)
2G
DTS-M1 / RA-2
2Gm (Interplanetary around Kerbin)
10Gm (Moho, Eve & Duna when close)
22.36Gm (Moho always, Eve, Duna & Dres (barely) if close)
15G
HG-55 / RA-15
5.48Gm (Eve when close)
27.39Gm (Always Moho & Eve, Duna & Dres if close)
61.24Gm (Dres, Jool & Eeloo if close, other planets always)
100G
Communotron 88-88 / RA-100
14.14Gm (Moho, Eve & Duna when close)
70.71Gm (Jool & Eeloo if close, other planets always)
158.11Gm (all bodies always)

Range calculation

Individual vessels do not have a fixed maximum range: whether a connection is possible between two vessels that are a given distance apart depends on the transmission strength of the vessels at both ends of the connection. Each antenna has a "power rating", measured as a unitless number, which contributes to the overall power rating of the vessel it is attached to. A connection can be established between two vessels when the geometric mean of their power ratings is greater than their separation as measured in meters. This is calculated as follows:

Where:
  • is the maximum distance in meters at which two vessels can connect with each other.
  • and are the power ratings for the vessels that are attempting to connect to each other.

Power ratings for antennae range from 5k for the integrated antenna available in every Command module, to 100G for the largest dishes. Kerbin's Deep Space Network can be treated as a vessel with a rating of 2G/50G/250G (depending on the level of the Tracking Station) for the purposes of calculating range.

Combining antennas

When a craft has multiple, combinable antennas, the antenna's power ratings stack in a way that provides diminishing returns using the following formula:

The vessel's Average Combinability Exponent is the average of the combinability exponent values of all antennas on the vessel, where each antenna is weighted proportionally to its respective power rating. Note that all antennas and relays have a combinability exponent value of 0.75 except for the Communotron 16 and the Communotron 16S, with values of 1.0 and 0.0 respectively. This means that the Average Combinability Exponent will always be 0.75 for a vessel containing neither of these antennae. For vessels with a Communotron 16 or 16S, the Average Combinability Exponent is calculated:

Where:
  • are the power ratings of each antenna.
  • are the combinability values of each respective antenna.

For example, a vessel with a Communotron 88-88 (100G power, 0.75 combinability) and also a Communotron 16 (500k power, 1.00 combinability) would have the following as its Average Combinability Exponent:

Antennae combinability exponent values can be found under "antennaCombinableExponent" in the part configuration files. If the value is missing, the default value of 0.75 is used.

Signal strength

The length of a communication link relative to its maximum range is represented by signal strength. Signal strength for a single-hop link starts at 100% at a distance of zero and decreases as distance increases, down to a signal strength of 0% at the maximum range of the link. The relationship is non-linear: the true value requires plotting the relative distance on a Bezier curve with the keys '0 0 0 0' and '1 1 0 0'. This can be calculated as follows:

  • Calculate the relative distance between the vessels (the result should be between 0.0 and 1.0):
  • Substitute the result above into the Bezier curve equation (cubic derivation): or

The result is the signal strength of the link at the specified distance. Note that the above applies to a single-hop link: if the signal is being bounced through one or more relays, the signal strength is the product of the signal strengths of each link making up the path to the control point.

Example

Calculating the Signal Strength between a Level 3 DSN Tracking Center and a probe around Jool at a distance of 73.4Gm from Kerbin with two Communotron 88-88 antennas:

  • Max Power of Lvl 3 DSN connection:
  • Max Power of Probe:
  • Max Range of Connection:
  • Relative distance between Link Points:
  • Signal Strength:

Therefore the signal strength for this connection would be 71%.

Connections through Relays

When considering the antenna power of your vessel, Direct Antennas and Relay Antennas combine to give you a 'Power' to calculate Signal Strength back to the KSC, however, if a different vessel is connecting through you to communicate with the KSC the Direct Antennas are disregarded in any calculations made.

Example

  • A vessel with a Communotron 88-88 Direct Antenna and a RA-100 Relay Antenna orbiting around Eeloo at a distance of 105Gm from the KSC, with a Level 3 DSN, will connect back to the KSC with a Signal Strength of 48% as both antennas combine to give an increased antenna 'Power' for its own direct connection.
  • A vessel rendezvoused with the above craft with a measly Communotron 16 will have to communicate back to the KSC through the relay as its antenna is not strong enough to communicate with the KSC directly. As this small, probe craft will only consider the RA-100 Relay Antenna on the relay craft when calculating its connection back to the KSC, the power rating of the relay vessel drops and therefore the Signal Strength will drop to 26% (please note the calculations for these numbers have been obfuscated from the example for easy understanding of the concept).

Please keep the above in mind when creating relay vessels for you other craft to connect through in the depth of space.

Effects of signal loss

Depending on your difficulty settings, several effects occur when the CommNet signal is lost, either from the KSC or a probe control point. This could be due to either electricty loss, out of CommNet range, or an antenna destruction. There is also a setting where you can force the signal to blackout when entering a body's atmosphere too fast.

SAS doesn't depend on the CommNet signal. It depends only on the ship's ability to use SAS (pilot or capable probe, kerbal XP or all probes have SAS settings).

Manned without a pilot

You will lose the ability to create maneuver nodes, or delete existing ones

Probe, require control unchecked

Your probe will lose three capabilities : rotation control (roll, yaw, pitch), precise thrust control (only 0 or maximum), and the ability to create or remove maneuver nodes.

If your probe is capable of locking a maneuver axis through SAS, it is advised to create a maneuver node before transmission blackout (passing behind a body) to allow the ship to perform the maneuver.

Probe, require control checked

You will completely lose control of your probe. Either wait for it to go back to a CommNet range, or send a ship with a probe control point capability to do general maneuvers (deploy solar panels, precise control,...).

DSN Strength

Each upgrade of the tracking center improves the strength of Kerbin's terrestrial-based Deep Space Network (DSN). Based on the provided figures, the Level 1 tracking station has an antenna strength of 2G, Level 2 is 50G, and Level 3 is 250G.

Science Transmission

Signal strength has no bearing on transmitting science directly to the KSC, but vessels transmitting through a relay will gain a 40% bonus to the data transmitted (to a maximum of 100% value). For example, a Gravity Scan from low Jool orbit would give 90*0.4=35 Science if transmitted directly, but if bounced through a relay with an overall strength of 100% would give 90*0.4*1.4=50.4 Science. This bonus decreases non-linearly with signal strength.

Difficulty Settings

Activate CommNet = If unchecked, all ships have full control, antennas still work but are just used to check range.

Required signal for control = Unchecked : probes have limited actions when out of range (full thrust only, SAS,...). Checked : probes will be uncontrollable until back in range.

Plasma blackout = If checked, a fast atmospheric re-entry might block the signal and put a probe in an uncontrollable state.

Range Modifier = The value of this slider is a multiplier value that is applied to the power levels of all Antenna and Relay parts.

DSN Modifier = The value of this slider is a multiplier value that is applied to the power level of the DSN Network.

Allow additional ground stations = Adds antennae on the surface of Kerbin, or else only the KSC has an antenna and you must build your own Kerbin relay sat system.

Tutorials, Calculators and Examples

A Google Sheets document that can help calculate Signal Strength and Ranges for you can be found here: CommNet Signal Strength Calculator & Antenna Selector

Example orbits for setting up a planetary network can be found at: Tutorial:Ideal Orbits for Communication Satellites

One method of setting up a full-system network can be found at Tutorial:Setting up a CommNet system.