And some more info....You cant measure the DC voltage or current out to the LNB without loosing signals, attaching a DVM or current meter without a very special interface with shut down the system, and you may get a false reading.
You may get a DC voltage reading at the end of the coax, or at the LNB input on the receiver, but this is an UN-loaded condition, and will give incorrect readings, all it will tell you is that there is not (or is) a DC short somewhere in the system.
I use a highly modified receiver to do this, this measure's the active system voltage and DC current draw of the LNB(s).