[Doug S]

I know that the BBC upconverts Ka Lo to the 1650-2150 MHz range when triggered by the IRD. What exactly is that trigger? I don't believe it is a 22KHz tone, is it a DiSEqC setting?

 

[curt8403]

I know that the BBC upconverts Ka Lo to the 1650-2150 MHz range when triggered by the IRD. What exactly is that trigger? I don't believe it is a 22KHz tone, is it a DiSEqC setting?

from what I have heard it is a DiSEqC setting

 

[houskamp]

higher voltage is the trigger IIRC..

 

[curt8403]

higher voltage is the trigger IIRC..

the hi band has signal at both 13 V and 18V how would voltage be the trigger?

 

[evan_s]

DiSEqC would make sense. Toms posted that it is used to select the 72.5 and international dish so it is already in use in some cases. Voltage would be hard to do as pointed out since it has to work on both 13v and 18v.

 

[2dogz]

My impression is that the BBCs are steady state, always on type devices. Can't be too much smarts in them as D* passes them out like candy. Correct me if I'm wrong.

 

[curt8403]

My impression is that the BBCs are steady state, always on type devices. Can't be too much smarts in them as D* passes them out like candy. Correct me if I'm wrong.

you may be correct, all they need to do is down convert the KA Hi band to KA Lo and that is it KU is passed untouched.

 

[evan_s]

My impression is that the BBCs are steady state, always on type devices. Can't be too much smarts in them as D* passes them out like candy. Correct me if I'm wrong.

I don't think so. They move the Ka lo signal from 250-750 mhz to 1650-2150 when activated. Since they allow diplexing OTA I assume they just block the ka lo when not activated. Otherwise the Ka hi is already at 1650-2150 which is why the Ka lo isn't already there in the first place. The only way the BBC could always be on was if it shifted the Ka lo to 2250-2750 above the Ka Hi. I'm pretty sure thats not the case because if it was a static shift like that I would expect it to just be handled by the Switch.

 

[sungam]

The receivers use a simplified form of DiSEqC to turn the BBCs On/Off. In B-band mode 250 to 750 MHz becomes 2150 to 1650 MHz.

 

[cartrivision]

I don't think so. They move the Ka lo signal from 250-750 mhz to 1650-2150 when activated. Since they allow diplexing OTA I assume they just block the ka lo when not activated. Otherwise the Ka hi is already at 1650-2150 which is why the Ka lo isn't already there in the first place. The only way the BBC could always be on was if it shifted the Ka lo to 2250-2750 above the Ka Hi. I'm pretty sure thats not the case because if it was a static shift like that I would expect it to just be handled by the Switch.

Exactly. The BBCs control whether Ka-lo or Ka-hi is sent to the tuners in the 1650-2150 range. They both can't occupy that frequency range at the same time, so there is no way that the BBCs can be static unswitched devices.

 

[Tom Robertson]

The BBCs are DiSeq controlled devices. I've heard they use a 3 byte command to activate and another command to deactivate.

They can't be activated all the time. As others have pointed out, they shift the frequency right into the other Ka frequency band, so they are either shifting or blocking. (If they didn't block, the diplexed OTA wouldn't work, btw.)

Cheers,
Tom

 

[P Smith]

Answered here (post#19).