How does a Dish System switch between 3 Sats

[MattJ]

On DTV I know that they use 13v/18v to switch between odd and even transponders (LHand RH). They then use the 22 KHz tone to switch between Sat A and B, and just mux the Sat C channels onto Sat B. So they really only switch between 2 sats.
Please correct me if I'm wrong on the above.

On a Dish system you can have 3 sats 110, 119 and either 61.5 or 148. They use the same LNBs, so voltage switch is the same, I think. But how do they switch between 3 sats and do they still use 22khz tone?

Just trying to figure all this out.

Thanks
Matt

[ElJefe]

Dish Network systems switch between satellites using Dish Network's own brand of switches. These switches do not use a 22khz tone at all. Instead the receiver sends a one byte command to the switch using the LNB voltages (13 and 18 volts) in a serial protocol, like the way a computer connects to a modem but a lot slower.

[MattJ]

Thanks

Do they still use the 13v/18v to select LNB polarity?

[ElJefe]

Yes, most Dish Network systems still use the 13v/18v polarity selection scheme.

However, newer DishPro receivers will send out a constant 19v when they detect a DishPro LNBF, which is stacked and has both polarities on the same cable.

[MattJ]

ElJefe, thanks for the info.

Now I have a new question, do any of the Dish Network switches include a diplexor, so that an OTA antenna can be accessed on all outputs of the switch, like some of DTV switches? Or what is the best way to diplex an antenna on 4 switch outputs? There must be something better than a 4-way splitter and 4 diplexors.

[JohnH]

The thing that is better is using separate cables for the antenna feeds as diplexing causes problems with the switch control signals from the receivers.

Some newer DISH receivers can handle up to 4 satellites.