You can add a satellite receiver to increase antenna diversity and improve reception if needed.
Before doing so, we recommend that you consult your telemetry log files first, as there may well be other factors at play that contribute to reception problems.
A good starting point is to review your lost packets.
This can be checked on your radio telemetry screen after each flight.
A number higher than 150ms will require further investigation.
The first step is to improve antenna layout, which is especially critical in models with lots of carbon. Proper antennas routing and antenna layout will eliminate most of the reception problems you may encounter.
Practically any Graupner receiver can be used as a remote satellite receiver.
It requires setting up a digital output channel as SUMD on the satellite receiver, which is then connected to the SUMDIN channel on the main receiver with a JR-style female/female connector.
Receivers with a SUMDIN channel input option are the GR-16, GR-24, GR-32, and GR-24PRO.
It is essential to understand that adding a satellite receiver does not create redundancy.
Satellite receivers improves signal reception as there are now additional antennas communicating with the radio transmitter.
Choosing a receiver to function as a satellite depends on the available space and location.
The farther away the satellite receiver can be installed from the main receiver, the more diversity can be obtained.
For example, installing the main receiver in the center of the model and a satellite in the tail will secure better antenna exposure at different angles during flight.
To set up the satellite receiver, follow our serial receiver Q&A instructions HERE.
The SUMD output will be available on CH6 on the GR-12 type receivers and on CH8 on the GR-16, GR-24, and the S-port on the GR-32.
If you decide to use the SUMD diversity receiver S1051, the SUMD output will be on the female connector (the male connector is for telemetry input)
MAIN RECEIVER SETUP
The SUMDIN input channel connection is on CH7 on the GR-16, GR-24 and GR-32 and CH-10 on the GR-24PRO.
Setting up the receiver to SUMDIN is done over the telemetry/settings & data view menu.
On the GR-16, GR-24, and GR-32, it can be found on the RX CURVE menu. The default for CH7 is a servo that needs to be changed to SUMDIN.
On the GR-24PRO it can be found on the first menu page on the bottom.
When setting a channel to function as SUMDIN input, it cannot be used anymore for servo output.
If you use that channel, for example, to control the secondary flap, you will have to map that channel on your radio to use another channel.
Satellite receivers can be helpful in certain situations.
The Graupner receiver line with the HoTT protocol are widely known to be very capable and reliable even at extreme distances without losing RF connectivity.
However, if you need that extra peace of mind, such an option may be a thing to consider.
I just wanted to ask for clarification on a couple of things regarding setting up a receiver as a satellite receiver. 1. On the satellite, when setting up SUMD to output (at channel 6 in my scenario) does the period need to be set from the default of 20ms to 10ms (since the satellite is sending out a SUMD signal on channel 6, thought it might be required to change the satellite to 10ms). Or does it not make any difference? 2. Does the satellite receiver need to be bound as Rx2 separately or does is it more like with Spektrum satellites where you only bind the primary receiver with the satellite connected and that binds both? Or wil it work either way? Binding as Rx2 probably makes more sense so you can switch telemetry readings between the two but I wasn't certain so just wanted to clarify. Thank you.
The output period is applied to the physical port of the receiver only. You will need to bind the second receiver as well. We have a video that shows how to switch between the telemetry of each receiver.