I tried an SWM8 on a single cable HR21 set up and did not get any signal on tuner 2 for any satellite and only had signal on 101 and 110, but not on 119 or 103c. This is a 5LNB dish. I also tried a WB68 multi switch and was able to get signal on tuner 1, satellite 101, 110, 119 and 103c (obviously no signal on tuner 2). I hooked up the 4 wires from the dish lnb to the SWM8 (the same as I did for the WB68), hooked up a cable to the SWM1 port and connected it inside to the swm port on the power inserter and then connected the IRD port on the power inserter to the HR21 sat 1 port (without the B band converter). The result was as stated above, no signal on tuner 2 at all and signal only on satellite 101 and 110.
Could it be that because I didn't do a red button reset of the receiver that I didn't get it to work?