Radio New Zealand - Te Reo Irirangi o Aotearoa

Why is RNZ National FM in mono and not stereo?

The main reason Radio NZ National is in mono is cost. It's more expensive to broadcast in stereo and as our highest rating programmes – news and talk programmes – are in mono and are listened to by many people on mono radios, we believe it is better to broadcast to those listeners than fewer people in stereo. (The cost of operating 20 mono transmitters is about the same as operating 12 stereo transmitters.)

There are some advantages of being in mono. Reception is better because the radio is not trying to decipher the complex stereo info and, because we can broadcast with less power (the equivalent stereo signal requires 5 or 6 times the power), we get less overloading and distortion from high power signals reflecting off buildings.

There are still lots of good reasons for us to broadcast Radio NZ National on FM:

• Better quality (audio bandwidth up to 15 khz rather than about 5 khz with AM
• Better audio bandwidth cuts through other noise better than AM (in the car, in the kitchen etc)
• FM signals penetrate into buildings and tunnels much better than AM
• FM is not subject to as much interference from electric light switches, computers, cordless phones, trolley buses in Wellington
• FM doesn't fade at night like AM does
• Doesn't get interference from distant stations at night like AM
• AM coverage has shrunk due to all the "man made noise" being generated by radio devices, PCs, cordless phones etc
• And the AM band is virtually full anyway so no more frequencies are available to expand networks without using FM
• Many radios and all mobile phones don't have AM bands
• Some people, especially younger people, don't listen to anything other than FM
• People expect FM/CD type quality now which AM can't deliver
• Being on the FM band means people surfing can come across RNZ National and hopefully stay listening
• FM also allows us to use Radio Data System - RDS radios automatically tune to the best signal when you drive around the country
  

Radio NZ National is in stereo on the web and on Freeview terrestrial.