u.s. tv network buoy strong demand advertisers add hours coverage week republican national convention compare four years ago plan use social media capture unexpected moments executives say presumptive presidential nominee donald trump may new politics former star reality show apprentice tv veteran promise throw traditional convention script provide showbiz feel add program uncertainty protest outside convention hall cleveland possibility dissent among delegate safe say go surprise say sam feist washington bureau chief cnn cable news network own time warner inc twx.n stake high broadcast cable network media analysts predict viewership trump acceptance speech could surpass record 38 million watch barack obama address democratic convention 2008. potential unexpected usually meticulously stag event drive strong advertiser demand network executives say cnn pull 40,000 100,000 30-second spot source familiar matter say far typical cost roughly 7,000 primetime ad cnn 100 percent sell primetime 95 percent sell slot say katrina cukaj executive vice president portfolio sales client partnerships cnn parent turner broadcast decline comment rat quick service restaurants movie studios run spot past conventions cukaj say advertisers lot diverse ever see cukaj say broadcaster cbs cbs.n see strong ad sales conventions book ads entertainment package goods travel industries network source say 2012 tv advertisers spend 5.8 million conventions compare 7.8 million 2008 accord kantar media cable network provide coverage throughout day even broadcast network plan one hour primetime coverage four nights plus online report 2012 broadcasters air hour last three nights cnn hundreds staff grind previous convention feist say first time channel anchor every show cleveland noon friday network face plenty competition fox news channel own 21st century fox foxa.o begin coverage cleveland thursday four days start compare sunday years past also add staff outside cover protest trump acceptance speech could attract 40 million viewers say kyle roberts president chief executive smart media group media buyer work republican candidates brand avoid convention say barry lowenthal president media kitchen media buyer dangerous territory lowenthal say unpredictable content sure convention go enhance brand image go go elsewhere media outlets say rely heavily year social media live stream msnbc correspondent jacob soboroff say expect broadcast live week television plan snapchat twitter possibly facebook live go different kind convention soboroff say feel like business usual lot energy around feel uncertain walt disney co dis.n abc news run six live stream simultaneously website apps live coverage cbs appear twitter 24-hour cbsn mobile app cbs prepare possibility trump appear role every night another break tradition cbs news president david rhodes say u.s. tv network amid strong ad sales boost coverage trump 's convention