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World-Of-Satellite

Multiswitch FAQ

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Default Multiswitch FAQ

To better understand how a multiswitch works with a satellite antenna, lets get an understanding of how the two work together.

The LNB on your satellite dish is capable of tuning to a satellite transponder that is broadcasting in either left-hand or right-hand circular polarity. A technical explanation of this is pretty involved and for the purposes of this explanation you'll just take our word for it. When you tune to a channel on your receiver, the receiver sends a switching signal back up the coax cable to the LNB in the form of a 14-volt or 18-volt DC voltage level to select the correct polarity for the transponder you have requested. This is why you cannot use a splitter for adding additional DSS receivers. If you do, the LNB gets a conflicting set of commands from the two sat receivers if they both try to access transponders of differing polarity. As a result, you can get a signal on one receiver while not the other if different transponders have been selected by each. You can set up two DSS receivers on a dish with a dual LNB using a dedicated line for each receiver. If you want to set up more than two receivers then you need a multiswitch.


A multiswitch is basically a box that contains splitters and A/B switches. The outputs of each LNB are connected to the A and B inputs of the multiswitch. In this configuration, one LNB is dedicated to left-hand polarity transponders and the other LNB is set up for right-hand polarity. The inputs to the multi-switch from the LNBs are split for either 4 or 8 outputs each (more if a larger multiswitch is desired). These split outputs are paired and connected to a series of A/B switches such that one side of the switch sees input A and the other side sees input B.


The outputs of the multiswitch are routed to each receiver you have in your household. When you tune to a channel, instead of the LNB being switched to the correct polarity, the 14-volt or 18-volt signal selects either transponder A or B by toggling the A/B switch. The LNBs are no longer switched when you change channels. Instead, the switching occurs inside the multiswitch (hence the name) and the correct polarity is selected for the desired channel/transponder.


Note that there are two different types of multiswitches available - passive (unpowered) and active (powered). If you have cable runs longer than 100 feet for any receiver, a powered multi-switch is highly recommended. The long run can degrade the voltage output from the receiver and the multiswitch may not work properly if the voltage drop is too great. A powered multiswitch detects the difference in the voltage levels and compensates for it.


1. What is a multiswitch and what is it used for?

A multiswitch takes the input from both of the LNB's (both cables from a dual LNB dish HAVE to be connected to the multiswitch)...it then locks one of the LNB's to always look at the even transponders and the other LNB to always look at the odd transponders. This is why a multiswitch only works with Dual LNBs and not single LNB's. The switch then has multiple outputs to receivers (4,8,etc). When you connect the receiver to the multiswitch, the switch determines which of the two LNB's the receiver needs to look at depending if it needs to view odd or even transponders. When you change the channel, the switch then swaps your connection to the other LNB when needed. With a multiswitch, the LNB's never change which side they are looking at.

2. What about multiswitches with Elliptical dishes?

If you have the oval dish with two "dual LNBs" (4 cables), each of the Dual LNB's look at different satellites (101 degree and 119 degree satellites). A multiswitch is needed to see the second satellite. A multiswitch comes with the dish and is usually have 4 outputs. Multiswitches for elliptical dishes need to have 4 inputs so it can switch between the 4 LNBs rather than the 2 in the explanation in question #1 above.

3. If my receiver sends voltage changes to switch between odd and even transponders on the 101 satellite, how does it tell the multiswitch that it wants to see the 119 satellite?

The receiver sends a 22khz tone over the cable along with the voltage change so it tells the multiswitch that it wants either odd or even transponders by the voltage and that it wants the 119 by sending the tone.

4. What is the 2x4, 2x8, 3x4, 3x8, 4x4, 4x8, 5x4 & 5x8 designations mean when referring to a multiswitch?

The first number in the number of inputs from the dish (or antenna) the switch has. The second number is the number of outputs the switch has.

A 5x8 multiswitch would handle 4 DTV inputs (Two Dual LNBs looking at the two satellites) and a Cable TV or antenna input if you wanted. It would have 8 outputs that could go to 8 DirectTV receivers, 4 Dual Tuner DirectTivos or any combo in between.

5. Can I connect two Multiswitches together (cascade one to another) to add more connections?

Well, that really depends. If you are using an 18" Dual LNB dish, then you could "cascade" two switches together....so you could take a 2x4 switch and have 2 of the outputs feed the inputs of another 2x4 switch to give you a total of 6 outputs. There are many issues that you have to be aware of though....length of cable, quality of multiswitches and whether they are powered or non-powered may affect whether or not this will work. If you have an 18x24" elliptical dish, it is a little more complex, but can be accomplished.

As mentioned above, the receiver will send a 22khz tone to tell the multiswitch that it wants the 119 degree satellite. This tone is only used by the multiswitch and is not sent back up to the LNB's....if you have two 4xn switches connected or a 4xn multiswitch connected to the built in multiswitch on a dish, the "2nd" one will never tell the "1st" one that it needs to see the 119 so the receivers connected to the "2nd" one would ONLY see the 101 satellite.

There are switches designated as "cascadable" that WILL send that 22khz tone upstream, thereby allowing you to connect it in series with another multiswitch (such as a built in one on the dish). These are more expensive than non-cascading models. The other way is to get "tone generators" which go on the two cables designated for the 119 satellite. They go inline between the two multiswitches (or between dish and multiswitch if you have the built in multiswitch on the dish). These tone generators put the 22khz tone on the line so that the 1st multiswitch (or built in one) sees the tone and puts that line over to the 119 satelllite.


6. There are SO many different multi-switches with a wide range of prices...which one is for me?

Lets start with the Differences Between Multi-switches. There are 3 main types of multi-switches:
[A] Non-Powered mechanical multi-switch - Cheapest in price. Has mechanical switching mechananism that is controlled by the power coming off of the DirectTV receiver. The DirectTV receiver changes voltages on the line depending on which transponder group it wants to look at. This multiswitch uses that voltage to move the switch.
[b] Powered mechanical multi-switch* - Mid range in price. Has a mechanical switching mechanism. It uses the voltage changes from the DTV receiver to determine what it should look at, but uses it's own external power to control the switch. Example of these are Channel Master and Terk multiswitches.
[C] Powered solid state multi-switch* - Most expensive. Completely solid state-no moving parts. Reads the voltage changes from the DirectTV receiver and electronically routes the signal to the correct LNB. Examples of these are Spauns, Trunkline, JVI.
*There are variations of [b] and [C] which include signal amplification.

7. How many inputs do I need?

If you have an 18" dual LNB dish, you have 2 outputs from the dish, therefore only need a "2 x n" switch meaning 2 inputs from dish and "n" output (to be determined at next step.

If you have an Elliptical dish (or 2 18" dishes looking at different satellites), you will need a "4 x n" switch meaning 4 inputs (from dish) and "n" outputs.

You will also see switches listed as "3 x n" or "5 x n"...This just means that there is an extra input for Antenna or CableTV. These switches allow you to combine an Antenna/CableTV signal onto the same RG6 cables as your DirectTV signal and split it out at the TV end. This saves you valuable cabling issues since you will only have to run 1 cable to a receiver instead of 2 (or 2 cables instead of 3 in the case of DirectTiVos)

8. How many outputs do I need?

This all depends on how many DirectTV receivers you have. You need 1 output for each receiver. In the case of the DirectTiVo, you need 2 outputs for each receiver. If you have two DirectTiVos, it would max out a 2x4 or 4x4 switch. Once you max out a switch, you cannot split to any other receiver and must get a new switch if you need to expand.

9. Non-powered, Powered/Mechanical, Powered Solid state, Amplified multi-switches... which one do I need?

Well, that depends on your budget and your setup. If you have very long cable runs (greater than 100 feet), you should definitely get a powered switch and better yet, a powered/amplified switch. A non-powered switch may work, but since it depends solely on the voltage of the receiver to move the switch, the voltage loss in long cable runs could make the switch unreliable. In the case of long cable runs, we recommend a switch like the Channel Master or Spaun. The Spauns are the most expensive and probably overkill for most people. Prior to that, I used Channel Masters and they were very reliable. Many users with non-powered multiswitches and some with long cable runs will get "Searching for Satellite" at times. We would not recommend non-powered cheaper switches unless your cable runs are very, very short.


Please here only good info (FAQ) All chat about Multiswitch search here:
http://www.sat-universe.com/showthread.php?t=127225
Regards

Last edited by ig0r; 11-07-2009 at 19:39.. Reason: about chat
The Following 5 Users Say Thank You to Rocknroll For This Useful Post:
aitchala (29-04-2007), ig0r (11-07-2009), Luciani (14-05-2007), RIDER (28-03-2009), tarey888 (31-08-2010)
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