I just bought a new 505. I already have a 505 hooked up to my HD monitor. I would like to hook up this one to my small LCD panel in the kitchen. I currently have an old dual stacked LNB. Do I need to put on a quad LNB to receive all channels on the new 505?

By dual stacked, do you mean single "can" with two outputs on an elliptical dish, or two "cans" on a dual feedhorn assembly, each going to a 2x2 switchbox.

If the former, yes you need to get a quad, if the latter, and the two 505s, no, you have all you need, if the latter and you are adding the 505s to existing receiver(s), you need to upgrade the switch, or switch to a quad.

A dual stacked is the Y shaped beer cans looking at F1 & F2.
He is already watching HD.
At minumim, they feed a 2x2 multiswitch, so it's very easy to just use the 2nd port of the multiswitch to feed an additional 505.

Now if he had other units or was adding a 530 with 2 tuners, then he's need the 2x4 or 4/5x8 multiswitches.

If you do change to a quad, then you would need *c to hit the units with a new channel map.

I'd say you are good to go as is.

The V-Code or Network status status should match.

Thank....Everything is A-OK.