What is the purpose of a satellite receiver?

[cjordan]

Greetings. This is probably a dumb question, considering I've been flying RC for 30+ years... I see that some folks are using a small satellite receiver in their aircraft that plugs into the main receiver.
I've been flying mainly Futable Tx and Rx forever and have never used a satellite receiver on any plane no matter how big or small. What the purpose?

[Gilatrout]

Remote receivers are mitigation for the donut holes shaped wave typically leaving the transmitter. It helps to ensure that at least one antenna on the plane is receiving signal.

They also provide backup reception for the possibility of battery, carbon fiber, or even a mess of wires blocking signal to the main receiver when the plane is at certain orientations with respect to the transmitter.

Remotes should be placed so that their antenna are 90degrees in orientation and not of the same horiz/vert axis of the main antenna.

[cjordan]

Thank you for the reply. So it's just added security to avoid signal loss. Are there specific receivers that you'd really always want to use a satellite with? As mentioned in my initial post, I've never had any signal interference or loss using just a standard receiver.

[Gilatrout]

Some receivers require at least one remote to be connected to either bind or initialize the esc. Not all park flyer receivers can have remotes.

It's not really a question of whether or not the receiver needs a remote or not. It is more about the model and your sensitivity to risk. A big investment in a model might mean you are interested in redundancy. A model like the FMS yak 130 might need the remote to prevent signal loss from the battery blocking the antennaa

For me, if I'm investing $400+ in a plane, I'm not going to cheap out and put a $50 parkflyer receiver. For really expensive planes I would consider strongly using a power safe receiver where both signal and power have multiple redundent backups.

[cjordan]

Thanks again for the feed back!

[Grantham Kid]

Spektrum RXs are equipped with Satellite receiver ports. Also Orange RXs will accept the Spektrum Satellites.

There are those that bind their RXs and Satellite RXs but only use the Satellite RX in small racing quads etc due to their size/weight. Once bound you don't need the main RX.

[fhhuber]

Not all Spektrum RXs have the satellite ports.

Orange also makes their own satellites.

The main RX is the one you plug the servos into... You always need that one.
Some Spekrum RXs require at least one satellite or they will refuse to bind. These will not function without a satellite.
Not sure of the current "Pwer Safe" RXs. I have some older DMX and DSM2 power safe RXs. They require at least 2 satellite RXs. I do not believe there is a "receiver" actually in these RXs, just the power distribution and logic systems. These will take up to 4 satellites.

If you bind an RX with the satellite all of the older Spekrum RXs I have (3+ years old) will see it as an error for you to not have the satellite plugged in and will refuse to function. You won't even take off.

[FlyingKOW]

Greetings. This is probably a dumb question, considering I've been flying RC for 30+ years... I see that some folks are using a small satellite receiver in their aircraft that plugs into the main receiver.
I've been flying mainly Futable Tx and Rx forever and have never used a satellite receiver on any plane no matter how big or small. What the purpose?

The only truly “dumb question” is the question which was never asked, thereby causing an unsatisfactory issue or result.

— DBA

[kallend]

The main RX is the one you plug the servos into... You always need that one. .

Many flight controllers for quads just use the serial signal from a so-called** satellite and decode that to control the machine - no "main RX" used at all, and they have no servos to plug into anything.

I have a heli that just uses satellites (2 of them, for redundancy) without a "main RX". They plug into a flight controller and that flight controller decodes the serial signal and drives the servos and main motor speed control.

** more accurate just to call them serial receivers, but they are no doubt mostly used as satellite or remote receivers in conventional models. Even there, some of the more expensive gyros for fixed wing will accept a serial signal from a so-called "satellite" and do all the signal decoding to drive the ESC and servos - no "main RX" required. It saves a lot of wires to do it that way.