My system has a DPP44 switch with 4 receivers on it. I want to hook up a 5th reciever. Can I use a SW64 with my DPP44 switch?
No you cannot. You cannot mix legacy equipment with DishPro (or Pro Plus) LNBs or switches. You may, however, acquire another DPP44, the much cheaper DPP33, or a cheaper still DP34 and cascade that off the passthrough ports of your DPP44.
... But if he already has a working DPP44 in the system then he already has the correct setup for that?The DPP33 will not work unless he is using 3 separate Dish Pro Dual LNBFs (the DPP33 does not work with DPP LNBFs). I don't think the DP34 will work, but even if it did it will take away your ability to use DPP separators, meaning that 2 lines will have to be run to each Dual Tuner.
The only way to go is adding on another DPP-44 switch
Here they are 149.99 shipped
I claim the OP can cascade a DPP33 or DP34 (or DPP44) off an existing DPP44. The rather large caveat being that you would only be passing 3 out of the possible 4 satellites connected to the existing DPP44. I forgot about 4-sat setups completely when I wrote my original post. Sorry about that.