The Ganymede Receiver Commander
Version 101

Ganymede Test & Measurement


The Ganymede Receiver Commander is a low cost microprocessor based device that enables the Nokia Mediamaster and other digital receivers to be seamlessly integrated into multi-satellite motorised systems. Version 101 is customised for the Echostar LT 8700 receiver/positioner. The Commander utilises the functionality of the LT 8700 to automatically control peripherals that are otherwise inaccessible to the digital receiver.


Key features:

The Commander monitors the 13/18V, 22kHz and 12V Auxiliary signalling states of the digital receiver to determine the polarity and LNB band of the wanted digital channel. Additionally, the Commander monitors the digital receiver’s DiSEqC antenna switching messages to determine which satellite is carrying the wanted channel. This information is then relayed to the LT 8700.

To signal to the LT 8700, the Commander emulates the Echostar’s hand held remote control unit. Band and polarity switching is accomplished by selecting one of four channels that are pre-assigned for the purpose. Dish positioning uses the Echostar’s ‘Select Satellite’ command.

To the end user, the action is transparent; selecting a channel on the digital receiver causes an automated sequence of commands to be generated which carry out all the functions necessary to receive the particular channel.

The Commander supports three modes of operation:

Universal Mode – if you use a Universal LNB with smart priority switch. The Commander provides dish positioning for up to eight user-programmable satellites.

Non-Universal Mode – if you use a conventional LNB/ polariser with power passing splitter. The Commander controls LNB band and polariser, and provides dish positioning for up to four user-programmable satellites.

Expert Mode – if you have access to a settings editor such as SETEDIT and have the knowledge and ability to re-program the Nokia firmware. In this mode, it is possible to control conventional LNB’s and polarisers AND have the eight satellite dish positioning function.

Installation is simple requiring no internal modifications to either digital or analogue receiver. Signalling from the digital receiver is acquired via a proprietary Power Inserter such as the Global DCBF*. The Commander also receives its power via this route. A second input from the digital receiver carries the auxiliary 12V signal..

To synchronise its dish-positioning operations, the Commander requires a ‘Motor Pulse’ input from the positioner motor. This is obtained from the rear panel terminal block of the LT 8700.

Signalling to the LT 8700 is achieved by means of an Infrared emitter which attaches to the Echostar front panel by means of a self –adhesive pad.

The first four entries in the Commander’s satellite table are factory pre-set to the Astra, Hotbird, Thor and Intelsat 605 satellites – corresponding to the four DiSEqC switch positions 1 to 4. However, these settings are easily re-programmable by the user to any other satellites of their choice. Also programmable is the remote control address of the LT 8700. The factory default address is zero.

User-programmed information is preserved during power down in non-volatile ram.

* Note: in Universal mode, the DCBF must be modified to pass power through the RF path. Modified DCBF’s are available from Ganymede Test & Measurement.


Short Specification

Characteristic Min Typical Max Units
Supply Voltage 12   20 V
Supply Current   10   mA
V polarity Sensing     14 V
H polarity Sensing 16     V
22 kHz Amplitude 0.5     V
Motor Pulse Input 3   5 V
DiSEqC Compatibility Level 1.0; 1-4 -


Interconnect Diagram – Universal Mode





Interconnect Diagram Non-Universal/ Expert Mode


For further information, including ordering information and the current price list, follow this link.

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Dr Overflow Software DVB98

The Commander 101 is fully compatible with Dr Overlow DVB98 software, version 66 and above. Use the Commander in 'Expert' mode (mode 3).

You can use an editor such as DVBEdit to set DiSEqC codes and 0/12 volt states according to your preferences. To use with the Commander's default settings, set up your channels according to the following table.

Satellite DiSEqC Code 0/12 Volt
Astra 1 0
Hotbird 2 0
1W 3 0
27.5W 4 0
Sirius 1 12
Astra2 2 12
10E 3 12
Other 4 12

You can download a settings file with these settings already implemented by clicking here.

DVB98 Configuration Table

To use the Commander, DVB98 must be configured as per the following table.

Menu Option Setting
5. I/O Space 5. 12V Chan. Low
9. DiSEqC Menu 0. Bit0 Band
9. DiSEqC Menu 1. Bit1 Pol.*
9. DiSEqC Menu 3. Mode Channel Mode
9. DiSEqC Menu 7. 22 kHz Band
9. DiSEqC Menu 8. 14/18V Pol.*
A. General Setup 1. LOF1 9750
A. General Setup 2. LOF2 10750
A. General Setup 3. LOF3 10750

* Not implemented in version 66


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Build your own Commander - Circuit Description and Component List


Ganymede Commander 101 Circuit Diagram


Component List

R1 47R
R2, R3, R11, R13 22k
R4 68R
R5, R6, R15 1k
R7, R12 470R
R10, R14 2k2
R8, R9 Not Used
C1 47m F; 16V
C2, C3 22 pF
C6, C7, C8 100 nF
C4, C5 Not Used
TR1, TR3 ZTX 304
TR2 Not Used
D1 15V; 0.125W
D2, D3 3mm flat top
IC1 LM78L05
IC2 16F84
XT1 NCZTA/2.0000/A


Circuit Description

Power input is at I/P1. R1 acts an HF stopper and provides limited isolation. IC1 is a voltage regulator which delivers exactly 5 volts for microcontroller IC2. Decoupling is provided by R4, C1 and C6.

The 22 kHz and 13/18V level detection are also obtained from I/P 1. The 22kHz is filtered via C8 and R12 and amplified by TR3 which saturates to provide a 0/5 volt swing at input port RA4 of IC2. This input is configured as a Schmidt trigger. 13/18 volt level detection is achieved via R2 and D1 where any level above approximately 16 volts turns TR1 fully on. A pull up resistor in IC2 port RB5 completes the circuit.

The 0/12 volt signal at I/P2 is attenuated by potential divider R14 and R15 to provide TTL logic levels at port RB0 of IC2.

Motor actuator pulses at I/P3 are buffered by R3. C7 provides HF filtering for input port RA0 of IC2. R13 is a pull down resistor.

Remote control signals for the Echostar are provided by the infrared emitter diode D4 which is powered directly from IC2, port RB1 via R7.

SW1 and SW2 providing set and program options. R5 and R6 are current limiting resistors for the LED’s D2 and D3.

IC2 is clocked by an internal oscillator controlled by ceramic resonator XT1 and C2/C3.

IC2 is a PIC 16F84 microcontroller which generates outputs according to the following flow chart.

Flow Chart (excluding user I/O*)

*User I/O program flow is detailed in the User Manual.


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