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DiSEqC a name for a Satellite switch used in the satellite reception industry every day .A name we take for granted ,what does DiSEqC stand for? The answer is quite straight forward DiSEqC stands for “Digital Satellite Equipment Control”.
The DiSEqC system is intended to provide a method of controlling several satellite inputs via a single down lead cable connected to the satellite receiver. This system addresses the problem of two satellites and two band systems very easily. It has dedicated outputs to select Polarity, Satellite position and Frequency band.
Over the years since the introduction of the DiSEqC system by Eutelsat, DiSEqC standards have grown to different versions which now provide additional functionality.DiSEqC is an open standard that stands for “Digital Satellite Equipment Control”. This DiSEqC standard currently features at least three versions:
1: DiSEqC V.1.0 can operate a two or four way DiSEqC switch.
2: DiSEqC V.1.2 provides additional functions that control not only the LNBF but also provides control and power from the satellite receiver to operate a DiSEqC 1.2 compatible motor such as the DMS International SG2100 or commonly known in New Zealand as the “ Moteck”motor to steer dish sizes up to one meter.
3: DiSEqC V2.00 provides two way communications for additional functions such as auto set up, diagnostics and other switching functions.
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DMS International 2 Way DiSEqC V.1.0 DiSEqC switch |
DMS International 4 Way DiSEqC V.1.0 DiSEqC switch |
DiSEqC specifications apply to Switches, Motors and satellite receivers. These DiSEqC specifications provide such functions which depend on the DiSEqC version supported.
Dual polarity operation on a dish fitted with two LNBF’s looking at different satellite locations “Optus D1 and Optus D2” can be controlled by a two input DiSEqC switch. Port A or 1 is allocated to Optus D1 and port B or 2 is allocated to Optus D2.
A four input switch would allow access to two other satellite signals. The inputs could be configured thus:
Port 1 Optus D1 / Port 2 Optus D2 / Port 3 Optus C1 / Port 4 another Ku input such as Asia Sat 4 or IS5
Please note that while some four input DiSEqC switches quite happily accept a mix of Ku and C band signals some do not and normally c band seems to be the problem port. The only remedy is to try several different types of DiSEqC switch until a suitable unit is found.
The dual Horizontal / Vertical LNBF output could also feed a multi switch for multiple receiver operation from the same satellite. It is very important to have an understanding of the combination types of equipment suitable for a specific Dish /LNBF installation.
For a fixed dish installation with up to four active LNBF’s or four individual dish / LNBF combinations a DiSEqC V 1.0 capable satellite receiver will suffice when mated with a V.1.0 DiSEqC two or four way switch.
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Optus D1 /D2 configuration using DiSEqC .V1.0 switch |
For a steerable dish Version 1.2 switches are recommended .The receiver issues commands via the LNBF input cable to the DiSEqC switch or motor which satellite to choose. The DiSEqC standard supports enough power to move the dish and motor providing the dish size is 1m or under.
For dish sizes larger than 1m it is recommended that a separate 36v actuator and positioner be used. The weight and wind loading of a dish larger than 1m makes it unsuitable for such motors as the Moteck or the DMS SG2100 which are essentially low power devices.
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Four separate dishes or four LNBF’s configured using a DiSEqC version 1.0 switch. |
So how does a DiSEqC switch work in a typical configuration? Messages are sent from the satellite receiver as sequences of short bursts of 22 KHz tone modulated on the LNBF power supply carried by the coax cable. This is connected from the LNBF input F connector on the satellite receiver.
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Typical configuration for DiSEqC Motor (Moteck) or (SG2100) |
ALWAYS TURN THE SATELLITE RECEIVER OFF AT THE MAINS SWITCH WHEN FITTING A DiSEqC SWITCH OF ANY TYPE.
By design, most DiSEqC switches do the same job. But when it comes to differences between them, I would say there are clear distinctions:
For example, the cheaper Chinese units have a tendency to break down.
When it comes to switching problems, there usually are a few good cures:
1) Getting a good DiSEqC switch (for example a DMSI or Pacific)
2) Grounding your setup to reduce ground/static issues with the DiSEqC switches
3) Ensure your LNB’s and cables are good
4) In a house with 2 receivers, turn 22 KHz ON for all satellites in one receiver, while turning 22 KHz OFF for all satellites in the other receiver. This helps separate the signal, even if you’re not actually using 22 KHz switches.
DiSEqC’ switches have a tendency to break. The best suggestion is ALWAYS turning off the power on the receiver (usually located at the back) before connecting or disconnecting any coaxial cables. Most people forget to do this which leads to the burning out the switches.
Remember: coaxial cables carry enough current to power LNB’s and even to move motors!
PURCHASE YOUR DISEqC SWITCHES FROM JX:
