Coba jelasin Audio dari Radio dalam bahasa sunda dong

Radio siaran AM ngirimkeun musik jeung ucapan dina spékrum gelombang radio Frékuénsi Sedeng (MF—0.300 MHz nepi ka 3 MHz).  Radio AM ngagunakeun modulasi amplitudo, di mana amplitudo sinyal pamawa dirobah proporsional jeung amplitudo sora anu katangkep (di-trandusi) ku mikropon sedengkeun frékuénsina tetep henteu dirobah. Pangiriman sinyal cara kieu keuna ku gangguan listrik statik jeung interférensi lantaran kilat sarta sumber gangguan lianna anu mancar dina frékuénsi anu sarua ngarobah amplitudo sinyal anu dipancarkeun. Ukuran daya paling gedé anu dimeunangkeun pikeun stasiun radio AM di Amérika Sarikat nyaéta  50,000 watts sarta lolobana stasiun anu mancar sakuat ieu geus karolot; stasiun-stasiun ieu di antarana WGN (AM), WJR, sarta CKLW. Dina taun 1986 KTNN mangrupa stasiun pamungkas anu narima idin operasi dina 50,000 watt.

Radio siaran FM ngirimkeun musik jeung ucapan kalayan kehandalan (fidelity) anu leuwih hadé ti batan radio AM. Dina modulasi frékuénsi, parobahan amplitudo dina mikropon nyababkeun frékuénsi transmitter fluktuasi.  Lantaran sinyal audio ngamodulasi frékuénsi lain amplitudo, mangka sinyal FM henteu keuna ku gangguan statik sarta interférensi saperti halna sinyal AM. FM dipancarkeun dina spéktrum gelombang radio Frékuénsi Luhur Pisan atawa Very High Frequency (VHF—30 MHz nepi ka 300 MHz).  Gelombang radio VHF watekna leuwih mirupa cahaya, ngarambat dina garis anu lempeng, antukna jarak panarimaan kawates antara 50-100 mil. Dina kondisi atmosfir bagian luhur anu henteu biasa, sinyal FM kadang dipantulkeun balik ka bumi ku ionosfir, ngakibatkeun jarak pancar FM anu jauh. Receiver FM keuna ku capture effect, anu nyababkeun radio ngan narima sinyal anu paling kuat mangsa aya leuwih ti hiji sinyal anu datang dina frékuénsi nu sarua. Receiver FM relatif kebal tina gangguan kilat jeung interférensi.

Daya nu gedé boga mangfaat pikeun nembus wangunan, nyebar sabudeureun pasir-pasir, sarta mengkol dina luhureun horizon. Akibatna, stasiun-stasiun FM nu dayana 100,000 watt bisa sacara régulér kadéngé sajauh 100 mil (160 km), malah bisa leuwih jauh deui (nyaéta 150 mil, 240 km) lamun euwueh sinyal lianna dina frékuénsi nu sarua.

Stasiun FM anu dijalankeun maké daya 320,000 watts ERP nepi ka 500,000 watts ERP henteu ngabantu pikeun manjangkeun jarak pancar sabab frékuénsi VHF ngarambat ampir mirupa garis lempeng dina luhureun horizon sarta nembus ka angkasa luar.

FM Sub-carrier services are secondary signals transmitted "piggyback" along with the main program. Special receivers are required to utilize these services. Analog channels may contain alternative programming, such as réading services for the blind, background music or steréo sound signals. In some extremely crowded metropolitan aréas, the sub-channel program might be an alternate foreign language radio program for various ethnic groups. Sub-carriers can also transmit digital data, such as station identification, the current song's name, web addresses, or stock quotes. In some countries, FM radios automatically re-tune themselves to the same channel in a different district by using sub-bands.

Aviation voice radios use VHF AM. AM is used so that multiple stations on the same channel can be received. (Use of FM would result in stronger stations blocking out reception of wéaker stations due to FM's capture effect). Aircraft fly high enough that their transmitters can be received hundreds of miles (or kilometres) away, even though they are using VHF.

Marine voice radios can use AM in the shortwave High Frequency (HF—3 MHz to 30 MHz) radio spectrum for very long ranges or narrowband FM in the VHF spectrum for much shorter ranges. Government, police, fire and commercial voice services use narrowband FM on special frequencies.  Fidelity is sacrificed to use a smaller range of radio frequencies, usually five kHz of deviation, rather than the 75 kHz used by FM broadcasts and 25 kHz used by TV sound.

Civil and military HF (high frequency) voice services use shortwave radio to contact ships at séa, aircraft and isolated settlements. Most use single sideband voice (SSB), which uses less bandwidth than AM. On an AM radio SSB sounds like ducks quacking.  Viewed as a graph of frequency versus power, an AM signal shows power where the frequencies of the voice add and subtract with the main radio frequency.  SSB cuts the bandwidth in half by suppressing the carrier and (usually) lower sideband.  This also makes the transmitter about three times more powerful, because it doesn't need to transmit the unused carrier and sideband.

TETRA, Terrestrial Trunked Radio is a digital cell phone system for military, police and ambulances.  Commercial services such as XM, WorldSpace and Sirius offer encrypted digital Satellite radio.