CommNet relay sats not talking with each other?

[etherealconstruct]

Hi everyone,

I've picked up KSP again recently and am trying to build a comm network local to Kerbin. For context: I'm playing on pretty hard settings, and I only have a ground comm station at the KSC itself, not anywhere else on the planet. This pretty much means that I need a comm network local to Kerbin itself. I'm at the point in the tech tree where I only have the 5M relay antennas. For various reasons it would be really nice to be able to launch and control probes around Kerbin (and due to settings I don't have probe control unless I have a comm-link). In case it's relevant I'm using the Kerbal Engineer plugin (automatic suicide burn and Δv calculations FTW!) and the latest KSP available for download.

My plan was a three-relay-sat constellation at 2.15Mm altitude (so a 2.75Mm orbital radius). Since the three comsats will form a equilateral triangle, that means by the law of sines the side length between any two comsats will be 2.75Mm * sin(3π/2) / sin(π/6) = 4.76Mm. This was based on the understanding that since the 5M relay antennas have a comm rating of 5M, that means the maximum distance two relays can talk with each other is √(5e6 * 5e6) = 5Mm. Since 4.76Mm < 5Mm, they should be in (low-signal-strength) contact with each other. However, I've placed two of the three relay sats (launching 2 at a time, for redundancy) and despite being almost exactly 4.76Mm apart from each other, there's no comm link. They can both talk with the ground station just fine, but not with each other --- the "network" and "vessel link" views don't show a link, nor can I control the one with an occluded link to the KSC.

What am I misunderstanding?

Thanks!

- ethereal

[bewing]

Hard mode reduces antenna ranges by a percentage. If you want them to go back to normal, go into your Difficulty Settings, and look for the "Range Modifier" in the Advanced Settings and set it to 1.

 

[etherealconstruct]

That would certainly explain things! Not quite sure how I missed it. Thank you!

[ArmoredLipid]

Put a relay satellite (henceforth designated the Base Relay) in keostationary orbit above the KSC. Place 2 more in orbit at 120 degree angles away from the Base Relay. Place another two in keostationary orbit over the poles, where the "horizontal" ring of satellites previously mentioned won't be able to see. Use the HG-5 High Gain Antenna for this purpose; it weighs only 0.07 tons and can easily be fit on a compact satellite - I have made ones that fit into 1.25-meter cargo fairings. Note that relay power can be combined; sticking 4 of them on a satellite will allow all 4 of them to transmit 1/4 of the data, and will allow for stronger connections.

My design for a Kerbin relay satellite is a Stayputnik on top of a Small Inline Reaction Wheel (Stayputnik has no reaction wheel) and Z-200 Rechargeable Battery Bank. On the reaction wheel and battery are 4 HG-5 High Gain Antennas and 4 OX-STAT Photovoltaic Panels.  Overall, this satellite weighs 0.43 tons, or 860 pounds. 4 strong Kerbals could lift this thing. 

Also, if you change out the Stayputnik for an OKTO, you can stick a stack separator on top and launch quite a few at once.

Edited June 22, 2018 by ArmoredLipid

[linuxgurugamer]

1 hour ago, ArmoredLipid said:

Place another two in keostationary orbit over the poles, where the "horizontal" ring of satellites

Please tell me how to get a sat into a keostationary orbit aboce the poles.  

You can’t.  The best you can do is to create a set of satellites in polar orbits.  They can be at keostationary distances, but wont be stationary 

[ArmoredLipid]

Come to think of it, polar orbits won't be stationary - they won't be rotating relative to Kerbin's central axis. In that case, make a set of 3 relay satellites that orbit at speeds that expose all 3 of them to one another at all times, and make them orbit over the poles. Additionally, try landing a relay on the near side of the Mun.

Again, relay strength stacks, so adding 2 or more relay antennas will solve your problem.

Edited June 22, 2018 by ArmoredLipid

[Gargamel]

One other comment @etherealconstruct, you are using relay antennas correct?   Some antenna's a direct connect only, and some are relays.  Relays will talk with everything, but direct antennas will only talk to relays or the ground station.  So if your commnet cloud is made up of direct antennas, they will only talk to the ground stations (or other relay antennas out there), nothing will be able to bounce a signal off of them.   Seeing how you are doing the math, I'm assuming you know this, but I've made this error, so I figured I'd mention it. 

Step one of trouble shooting:  Did you plug it in? 

 

Edit: now I see you did say relay, but I'll leave this here, somebody might use it. 

Edited June 23, 2018 by Gargamel