satellite TV transmissions operate in 2 different radio frequency bands: C band and Ku Band
C-Band frequencies are between 3600 MHz and 4200 MHz, and usually require a large satellite dish, like used to be common in the 80's in North America. Many of those dishes are made of mesh pannels
Ku-Band frequencies are between 10700 and 12750 MHz, and can usually be received with a much smaller dish (18 inches to 4 feet or more depending on the satellite and location). This is what's used by the Direct-to-Home services such as DirecTV and Dish Network, but is also used by many other TV services. In North America, most signals are in the 11700-to-12200 MHz part of Ku band
In Ku band, as mentionned in my earlier post, there's Hispasat and also several North American satellites, particularly Galaxy19 @ 97W broadcasts about 180 unencrypted channels, mostly foreign or religious. Lots of stuff from Africa, Eastern Europe, Middle East.
In C-Band, the majority of the channels are either US domestic channels, Brazilian channels and Spanish Latin-American channels. But there are also a handful of channels in French, Korean, German, Chinese, etc
Look at the channel lists on Lyngsat.com and sathint.com. Those where the frequency is a 4-digit number are C-Band and those with a 5-digit number are Ku.
Keep in mind that PR might be outside of the footprint of many of those satellites. Lyngsat has some maps. Another good source for footprint maps is satbeams.com
As you can guess by the dish size, a Ku band system is a lot smaller, and easier to install, but then a C-Band system is a lot more rewarding in terms of content.
New C-Band systems are getting a bit hard to find, with only a few resellers catering to residential customers, but old dishes from the 80's can often be found for free from people willing to get rid of their old systems. This might not be so easy in PR after the recent hurricane though.
As for the feedhorn, it's the part that goes at the focal point of the dish and feeds the radiowaves to the LNB, the electronics that converts the radiowaves to electrical signal to be sent to the receiver. Nowadays the feedhorn and the LNB are integrated into one piece called LNBF.
I hope this helps, always feel free to ask questions!