A very interesting story!

http://www.msnbc.com/news/936772.asp?0cv=CB10&cp1=1

U.S. satellite feeds to Iran jammed
May be linked to the anniversary of student uprisings
By Robert Windrem
NBC NEWS PRODUCER

NEW YORK, July 9 - U.S. government officials as well as
Iranian Americans and communications satellite operators
confirm that all U.S.-based satellite broadcasts to Iran are
being jammed by an unknown group or individual, possibly
Iranian agents operating out of Latin America.

OVER THE PAST several months, private Iranian-American
groups have begun increasing their broadcasts into Iran using
Telstar-12, a communications satellite over the eastern Atlantic.

All are trying to encourage protests against the regime in Tehran.
Iranians, using small satellite dishes, have been able to receive
the broadcast, whose mix of news, entertainment and exhortations
to protest have gained a large audience, particularly in Tehran.
Then on Sunday, the Voice of America began its Farsi-language broadcasts.
Not long afterward, the jamming intensified.

Over the past few days - as the fourth anniversary of the country's
most widespread protests approached - the broadcasts
have been jammed, not in Iran but somewhere in the
Americas, according to officials and investigators.

(full story at the above link)