Antenna connection questions

[Tubal]

So I was going to be clever and make my Duna mission have both a relay satellite and a probe with an experiment storage unit that could return to kerbin. For some reason though, when I detach the probe to send it back it immediately loses connection.

The relay satellite has control, a connection and both a direct dish and smaller relay dishes. The probe has a small direct antenna (Communotron 16-S), power, probe core etc, but it doesn't connect to kerbin. If I bring up the map view when they're detached I can see a network line between the ships, and one going from the relay satellite back to Kerbin. If I hyperedit the probe back to kerbin orbit it connects.

What is going wrong?!

Going crazy over here, thanks for any help

[zolotiyeruki]

The only thing that comes to mind is power issues--does your relay satellite have batteries, and is it oriented so the panels face the sun?  Is there something else that's drawing too much power?

[bewing]

Relay sats cannot use a direct antenna effectively. The direct antenna does not boost relay range. A relay antenna does everything that a direct antenna does, but adds the ability to relay messages. So the problem is that the relay antennas do not have the range to communicate to Kerbin.

 

 

[Tubal]

It can't use the relays and direct antenna in combination?

[bewing]

1 hour ago, Tubal said:

It can't use the relays and direct antenna in combination?

nope -- relays and direct don't combine.

[Tubal]

Well chucks...

 

Thanks for the answers though. I guess my mission to Eve is going to need some new plans!

Edited September 28, 2017 by Tubal

[Spricigo]

2 hours ago, Tubal said:

It can't use the relays and direct antenna in combination?

For your currently controlled vessel you can. Relay antennas can do everything direct  antennas do.

For relays you cannot. Direct antennas cannot do everything relays antennas do.

 

[Geschosskopf]

On 9/28/2017 at 10:34 AM, Tubal said:

So I was going to be clever and make my Duna mission have both a relay satellite and a probe with an experiment storage unit that could return to kerbin. For some reason though, when I detach the probe to send it back it immediately loses connection.

The relay satellite has control, a connection and both a direct dish and smaller relay dishes. The probe has a small direct antenna (Communotron 16-S), power, probe core etc, but it doesn't connect to kerbin. If I bring up the map view when they're detached I can see a network line between the ships, and one going from the relay satellite back to Kerbin. If I hyperedit the probe back to kerbin orbit it connects.

What is going wrong?!

Going crazy over here, thanks for any help

Direct antennae have very short ranges.  AFAIK, none of them can talk to Kerbin from other planets, they need to go through a relay.  But they can only use relays that are within their short ranges, too.

If I understand your mission correctly, the relay is staying at Duna and the probe, with only a direct antenna, is returning to Kerbin.  So what I think is happening is that once the probe gets far enough from Duna, it can no longer use the relay.  And it's still too far from Kerbin to reach that, either.  Thus, no communications.

The network lines can be confusing.  If you have 2 different types of antennae on each end of a link, sometimes the stronger antenna will show a link even if the weaker is out of range.  Sometimes you can change this by making sure the active vessel has the weaker antenna, and setting the network to display path or 1st hop, but this doesn't always work.

[Curveball Anders]

I've several such missions, the latest one today (at Dres).

So the concept works perfectly but with only one relay there's always the issue of radio shadow.

I had to fiddle a bit with the departure of the science return vessel (with only short range comms) to have the relay I left behind have connection with Kerbin and having the connection between the two.

[Eric S]

3 hours ago, Geschosskopf said:

Direct antennae have very short ranges.  AFAIK, none of them can talk to Kerbin from other planets, they need to go through a relay.  But they can only use relays that are within their short ranges, too.

This isn't true.  For every relay antenna other than the shortest ranged one, there's a direct antenna with the same rating and significantly less mass.  The RA-100, the longest range relay antenna, with a 100G rating, is matched by the Communotron 88-88, a direct antenna having less than 8% of the RA-100's mass.

Only the smallest relay antenna is deployable,  so I tend to put the larger ones in fairings.

 

[Geschosskopf]

1 minute ago, Eric S said:

This isn't true.  For every relay antenna other than the shortest ranged one, there's a direct antenna with the same rating and significantly less mass.  The RA-100, the longest range relay antenna, with a 100G rating, is matched by the Communotron 88-88, a direct antenna having less than 8% of the RA-100's mass.

Only the smallest relay antenna is deployable,  so I tend to put the larger ones in fairings.

But what direct antenna was on the probe?  Looks like the non-deployable double-dipole to me.  That can't talk from Duna to Kerbin.

[Eric S]

29 minutes ago, Geschosskopf said:

But what direct antenna was on the probe?  Looks like the non-deployable double-dipole to me.  That can't talk from Duna to Kerbin.

That one, true.  In fact, I've had problems every time I've tried to use that one, even from LKO, though that may be a mod issue.  I was just correcting the generic "direct antennas can't reach other planets" statement.  "This direct antenna" would have been accurate.

[Spricigo]

1 hour ago, Geschosskopf said:

But what direct antenna was on the probe?  Looks like the non-deployable double-dipole to me.  That can't talk from Duna to Kerbin.

In any case the power of the direct antennas is not the issue there.

The HG-55(direct antenna) in he main ship  is powerful enough to connect direct to  Kerbin.

The 16S (direct antenna) is powerful enough to connect to a nearby relay for the departure maneuver, and to kerbin at the time of capture/landing. 

But the HG-5 (relay antenna) is not powerful enough to reach kerbin. That is the issue: the relay antenna is too weak.

[Tubal]

I wanted to use a large direct antenna to communicate with kerbin, and small relay antennas to spread the signal in the Duna system, but apparently that does not work.

[dvp]

30 minutes ago, Tubal said:

I wanted to use a large direct antenna to communicate with kerbin, and small relay antennas to spread the signal in the Duna system, but apparently that does not work.

Yeah, you'd have to do it the other way around - small local antennae, and a big relay.

[Spricigo]

5 hours ago, Tubal said:

I wanted to use a large direct antenna to communicate with kerbin, and small relay antennas to spread the signal in the Duna system, but apparently that does not work.

That 'make sense' but unfortunately is not how stock commnet works.