Okay, so from the reading I’ve done, there seem to be two types of Ku linear LNB’s, called Standard and Universal. The Standard type covers 11.7-12.2GHz, and the Universal covers 10.7-11.7 as the “low band” and 11.7-12.75 as the “high band”. Note that the Standard can’t reach above 12.2, but the Universal can.
All these units are intended to be bolted to a dish, so in order to receive both V and H polarized signals without the user having to run outside and twist the thing, they have an electrical means to select which signal probe in the feedhorn is active. This requires the receiver to tell the LNB a bit of information, and this is done with the power that’s superimposed on the coax.
The Standard LNB only needs to select polarization, so they do this with the power voltage. It’s either 13v or 18v, to select V or H, respectively. (And if you only need one, never switching, you can just source 13v and twist the unit until it lines up with the signal you want.)
The Universal type, on the other hand, needs to select both its polarization and its LO frequency. Two bits of data. So in addition to the voltage choice, the other bit comes as the presence or absence of a 22kHz tone superimposed on the power. Here again, the voltage selects the polarization, and the tone selects the band. High band requires the 22kHz tone to be present, for all the Universal LNB’s I’ve looked at. I think this is common across the industry. Without the tone, supplying pure DC, a Unversal LNB will only receive the low band.
Sooooo what? So, I need to know if the DC3 board can generate the 22kHz tone! If so, I can get a Universal LNB and be able to reach anywhere in the high band, including the 12.2-12.75 region that Standard LNB can’t cover. But if there’s no tone support, then I need to get a Standard LNB and hope the signal is always below 12.2, within its range.
Syed has said “Standard LNB”, but also “11.7-12.75”, so I’m a little less than certain.
Of course, I don’t want to merely receive Outernet, I also want to nose around this new band that’s caught my interest. (Who else might be packing data into DVB-S2 payloads, after all?) Which means I need a way to power my LNB and get the signal to my SDR. Bias tees are easy enough if I’m supplying DC, but if I need to superimpose a tone, I think it’s simpler to follow Gough Lui’s strategy and pick up a receiver with a loop-through port. The thinking is that a cheap FTA receiver will handle the LNB power and band selection for me, leaving me a simple loop output that I can pipe to my SDR. So with that in the path, I think I should be able do the needful with a Universal LNB, regardless of whether the DC3 will make 22kHz on its own.
My kingdom for a DIP switch. Oy.