I'll tell you, this satellite business in quite interesting to say the least!
It is the "communications" business, yet it is typical for very little "communicating" to go on.
This is between manufacturers and customers and between manufacturers of different equipment.
Besides the manufacturers providing few or no instructions with the equipment you buy...
your typical C-band dish requires a two wire 36 volt connection to move the dish, a two wire sensor connection to the positioner, a coax connection to the LNB, and a 3 wire connection to the "polorizer" (H/V) on the LNB "feed horn".
OK fine!
Most receivers say they can receive C or Ku, YET there is NO connection on the receiver for 36 V, OR the two wire sensor, OR the 3 wire polorizer!
So how exactly are you supposed to get C band with these receivers?
Note: They will work fine with a smaller Ku dish with a diseqc positioner and coax cable 13/18 volt controlled polorizer (H/V).
So it is possible to buy a C setup which will not work. A couple of manufacturers have "come to the rescue" though!
There is a coax "diseqc to 36 volt" positioner add on unit to solve part of this problem...
http://www.sadoun.com/Sat/Products/Moteck/V-Box-II-control.htm
And there is a C/Ku LNBF which easily mounts to a prime focus dish which controls the H/V via the coax (need to get correct model for your receiver BSC621 or BSC621-2)...
http://www.sadoun.com/Sat/Order/LNBFS/C-Band-LNBF.htm