Dish Network "Legacy" LNBFs and Switches

"Legacy" is what Dish Network calls standard satellite equipment. Dish legacy equipment are essentially industry standard/generic components that convert the incoming K_u band satellite signal to an intermediate frequency (IF) of 950-1450 MHz. You'll notice that this is only half of the 1 GHz bandwith of the satellite. This is because the LNB only converts half of the satellite's transponders to the IF at a time. The receiver sends 18V down the line to select odd transponders and 13V to select even transponders. When a dual output LNBF is connected to a switch, odd and even transponders are carried to the switch on separate cables and the receiver selects odd or even transponders by sending voltage to the switch.

This equipment is universally compatible with all Dish Network receivers except for the Hopper and Joey. Dual tuner receivers require a separate line to the switch/LNB for each tuner.

Click on the thumbnails for a larger image.

Single/Dual

Comes in two versions - the single has a single voltage switched output to connect to a single satellite receiver, the dual has two voltage switched outputs to connect to two satellite receivers, or a switch to connect three or more receivers. The original "Dish 300" picked up a single orbital location, 119°, using a 46cm dish and a single or dual LNBF. The first "Dish 500" setups used two dual/single LNBFs connected to an SW21 or SW44 multiswitch. Echostar made their own Dish branded LNBFs which are identifiable by their label which reads dish Digital LNBF. These were made in the US and Japan and are extremely durable, I've found many LNBs installed in the 90's which have a lower noise figure and LO frequency drift than new equipment. The one in the picture has downloaded over 73,000 terabytes of data. Dish no longer makes or supplies these, but other companies do. Other popular brands compatible with this line include Cal Amp, Zinwell, and Eagle Aspen. LNBs in this line from Dish and others are compatible with all makes and models of satellite receiver, including DirecTV. When connected to a Dish Network receiver, the legacy dual will show up as a "none" after a check switch, meaning no switch was detected.

Twin

The twin is the LNBF most commonly used on older Dish 500 setups. It contains two LNBFs for receiving signals from the 119° and 110° orbital locations and an integrated proprietary multiswitch. The receiver selects odd or even transponders by sending 13V or 18V, and selects the orbital location using proprietary DiSEqC code consisting of a series 22 kHz tone bursts. The DiSEqC switch is built in, so there is no need for an external switch. There were two versions of the twin, one with two outputs (Twin dual) and one with four outputs (Twin quad). These show up on a check switch as "Twin".

"Legacy" Switches

Several standalone switches were produced. Like the switch integrated into the twin, they all use DiSEqC v1.0 which provides for one-way communication from receiver to switch. DiSEqC commands consist of a series of timed 22kHz pulses, so any component that blocks 22kHz signals placed in the line between the switch and receiver will cause the receiver to fail to communicate with the switch. Performing a "Check Switch" test takes a very long time on all legacy equipment, the receiver will display something like "Performing test: 1 of 35" or something similar depending on the specific switch. All DiSEqC commands used on Dish Network switches are proprietary, meaning that standard DiSEqC and 22kHz "tone burst" switches are incompatible.

Generic

Because the LNBs use voltage switching, you can't use a splitter to distribute signal to multiple receivers. These are standard voltage controlled switches that provide one orbital location to three or more locations, most commonly 4, but commercial switches are available with 16 outputs. Commonly these switches incorporate a diplexer connected to all of the outputs. There are two inputs, one for even and one for odd, which are held at 13V and 18V respectively. The outputs are connected to the receivers which treat the switch as an LNB, selecting even or odd via voltage. These switches contain no DiSEqC logic and are universally compatible with all satellite equipment including Dish Network and DirecTV. Dish Network receivers are compatible with all "single satellite" switches regardless of manufacturer. Some multi-satellite switches, such as those intended for DirecTV have limited compatibility. When connected to something like the Zinwell SAM-4803, the Dish Network receiver will ignore any LNBs connected to the 22kHz ports, since they don't support 22kHz on/off switching.

SW21/SW42

This is a simple 2-in/1-out switch that can select between two separate orbital locations using DiSEqC 1.0. Voltage signals are passed through the switch unaltered - the voltage switches in the LNBFs are used to select between even/odd transponders. It shows up after a check switch as "SW22/SW42"

SW44

This switch has four inputs consisting of odd and even for two separate orbital locations, and four outputs for four single tuner receivers or two dual tuner receivers. More outputs are available by cascading multiple SW44s. Selection between orbital locations is via DiSEqC 1.0 and selection of odd/even is via voltage. A common setup in the early days was two duals mounted to a Dish 500 for 110° and 119°. The SW44 requires a power inserter, which is connected to output 1. This switch shows up on a check switch as "SW42/SW44".

SW64

This switch has 6 inputs - odd and even for up to three orbital locations, and four outputs for four single tuner receivers or two dual tuner receivers. More outputs are available by cascading multiple SW64s. Switching between orbital locations is via DiSEqC 1.0 and switching between odd/even is done via voltage. This swith is relatively uncommon, its main use was with a Dish 500 for 110° and 119° and a wing dish for either the 61.5° or 148° orbital location for local channels. This switch requires a power inserter connected to output 1.

Advanced Switch Topologies

SW44 Substitute

An SW44 equivalent can be constructed with two four-output generic multiswitches and four SW21 switches. Connect one orbital location to each generic multiswitch, then run the outputs of the generic multiswitches to the inputs of the SW21 switches as shown in the diagram below.

Cascading Switches

When more than four receivers are needed, multiple SW44 or SW64 switches can be cascaded using splitters. To send two orbital locations to eight locations you will need two SW44 switches, four two-way splitters and two "dummy loads". Splitters should be rated at up to 1450 MHz and DC passing on one port. Connect all four incoming lines from the two LNBFs to the inputs of the splitters, connect the power passing sides of the splitters to the inputs of the first switch. Connect the power-blocking sides to the inputs of the second switch, putting the dummy loads between the splitters and ports 1A and 2A on the switch. The dummy load simulates the current draw of an LNB, without it the receiver will not recognize any LNBs connected to that port. Dummy loads can be omitted if you'e using diode-steered splitters that pass power on all ports, but be certain to connect the same ports on both switches to same splitter to avoid switch-destroying current loops. In the diagram below the DC passing leg of the splitter is color-coded red and the passive leg is blue.

It's technically possible to cascade more than two switches, but to keep the noise figure to an acceptable level you should avoid running more than three switches (via three-way splitters) from the same LNB. Cascading SW64s is the same procedure, but you'll need three dummy loads and six splitters.