The Slingbox uses an IR Blaster to control your satellite/cable box. It sticks to the top of your box with the beam in front of your satellite box sensor. It plugs into your Slingbox and is controlled via a virtual remote on your computer screen. I don't think you can use the raw satellite signal as your second signal for a Slingbox Pro-HD. You can use a cable box or OTA antenna. You should be able to load the Slingbox software on any computer, but you will only have one account and can only access your Slingbox with one computer at a time. If you try to access it with a second device, you have to bump the other device off. The $29.99 mobile phone application is for each device. Again, you only have one account and can access your Slingbox with only one device at a time. That includes computers and/or phones.
Thanks for the info. Would you know the difference between the Slingbox HD pro 200 and 300 models? Also, how reliable is the HD stream when viewed over the Internet from a remote location? I travel alot and my thought of the Slingbox would be so when I am on the road I can watch my local broadcasts and DVR. When watching over the Internet, is there much a diffence between the HD picture vs the SD picture from the Slingbox solo? Does the HD picture get jitty? Is the SD picture more reliable?