Passive SAT-splitter

This simple splitter allows to split IF signal coming from an LNB to two DVB-receivers. Using this splitter you should be sure that all the channels from received satellite are placed in one defined polarization and subband (i mean the low-band and the high-band of the Ku-band). But the high-band (when used 22kHz-tone) and horizontal polarization have higher priority. The splitter was developed as cheap alternative of twin-LNB, but anyway a twin-LNB is more universal and reliable. I am using three same splitters and i'm for the moment satisfied :)

Schematic diagram of splitter:

Using example:
SAT-Splitter using example

Assembling example:
Assembled device


Using example:
HV-Switch Using Scheme
H/V-Switch Circuit
Self-made construction view:
H/V-Switch view 1 H/V-Switch view 2


Using example:
Using of 0/22kHz-Swith
22kHz-Swith Circuit

H/V+0/22kHz Combo-Switch

Combo H/V+0/22kHz Switch Logo

This is an attempt to combine together two well known kinds of switches, which are used in the practice of the satellite reception. The so called "Combo-Switch" was useful for obsolete receivers with only DiSEqC 1.0 level support and it solved the problem with more than four LNBs connection to one receiver. In fact, at the moment almost all receivers have a support of the full range of DiSEqC levels. Each input of the combo-switch will be active during its own condition. For example when the polarization is vertical (13V) and the subband is high (22kHz ON). Sure, you should consider features of broadcasting of satellites you are using (subbands and polarizations).

The equivalent schematic of the Combo-Switch :
The equivalent of the Combo-Switch
Using example:

Maximum capability using example:

Schematic diagram:
Combo-Switch Circuit
Schematic Diagram Enlarge

PCB of Combo-Switch (P-CAD):
Combo-Switch board in P-CAD

Example of manufacturing:
Example of manufacturing of Combo-Switch

Combo-Switch.pcb - Combo Switch PCB (PCAD 2004)

DiSEqC 2.0/1.0 Switch schematic diagrams

DiSEqC 2.0/1.0 Switch 4x1 schematic diagram using EM78153S02:

DiSEqC 1.0 Switch 4x1 schematic diagram using HS108N / DWS62K3:

DiSEqC 2.0/1.0 Switch 2x1 schematic diagram using MC68HC908QT4 (Motorola):

More info about some models of DiSEqC-switches is here.

Lumax LX-LST40 Single Universal LNB schematic diagram and pictures inside

I have disassembled this LNB to draw a schematic diagram of an LNB, since I couldn't find any schematic diagram of such device.

How it looks in the beginning:
Lumax LX-LST40

The LNB without plastic case:
Lumax LX-LST40

Is very hermetic... It's really hard to remove!
Lumax LX-LST40

The LNB after some actions:
Lumax LX-LST40

The back side of the top cap:
Lumax LX-LST40

So, we can see a PCB inside the LNB chassis:
Lumax LX-LST40

The PCB without the chassis:
Lumax LX-LST40
Click to enlarge

And the back side of the PCB:
Lumax LX-LST40

Simplified schematic diagram of the LNB:
Lumax LX-LST40 schematic diagram

The most interesting thing is that the transistors (NE4210S01 from NEC) used in the first stage have typical noise figure 0.5-0.7dB depending on frequency and other conditions. At the same time the whole LNB's noise figure is marked as only 0.3dB! Fantastic? Take this fact into account when buying a new "super low noise" LNB.

Download large picture of the schematic (9452 downloads)
See also more pictures of another type of LNB here (Pauxis DX-2200).

Please, do not distribute it at forums. The schematic diagram may contain discrepancies.

to be continued...

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