It’s here, but can you hear it?
One of the most frequent questions we got has to do with HD Radio’s signal coverage.
From what we have been able to learn to date, a station’s HD Radio signal should be just about identical to its conventional, analog AM or FM coverage. There will be areas where you will be able to hear only the analog signal and areas where you will be able to hear only the HD Radio signal.
Notice I said “should be just about identical.” This is because some sources say this just isn’t true. “We were told back in the beginning that the HD coverage would be equal to the analog signal,” says Robert Conrad, respected owner of WCLV-FM. “Unfortunately, the industry is now finding out this is not the case, that the HD coverage is considerably less, something like 60% of the analog coverage. We’ve also found that even in a strong HD signal area, a dipole antenna is required.”
On the other hand, Radiosophy, a manufacturer of HD Radios says this about signal coverage.
“Determining the useful coverage area for a radio station is somewhat complicated. Local terrain, other radio signals in the area and man-made interference can all affect how well you receive a given station. Plus, a radio signal will travelfor a very long distance past the area where we, as listeners, think it sounds acceptable.
“Because of these factors, each radio station has a coverage area that is broken into 3 different levels: local coverage, distant coverage and fringe coverage.
Local coverage is the area where the radio signal is strong and almost any radio should get good reception.
Distant coverage often requires a radio with a good antenna, and smaller portable radios may not receive the signal.
Fringe coverage is the area where reception is possible only with a good external antenna, if at all.
An HD capable radio should get reliable digital signals in the local coverage area, and may get digital signals in distant coverage areas, depending on the environment. Radios in fringe areas usually don’t receive digital signals, because unlike a traditional analog signal that fades out as you travel away from it, digital will simply disappear when the signal isn’t strong enough.
Finally, one of my visitors who works for an HD Radio manufacturer, basically said, “it depends.” He also pointed out that there are a number of factors that go into an HD Radio signal, including interference, the height of the station’s antenna, the transmit power level, etc. He went on to write, “For FM, digital is generally received out to the 45-50 dBu field strength contour.” This means, you would have to get a coverage map of the station to translate that into miles. Click here to find a list of stations within a given zip code that have a field strength of more than 50 dBu.
The Good News
The good news is that if your HD Radio signal disappears, your HD Radio will automatically switch back into analog mode.
I believe that signal coverage will not be a problem if you live in a metropolitan area or an area close to your favorite HD Radio stations. However, if you live rural and have problems picking up conventional analog stations, than HD Radio could be a problem, too.
Also, keep in mind that HD car radios will show more variance in station reception than a tabletop radio or component receiver which basically sits stationary in your home.