HD Radio broadcast

[joehawth]

I haven't found any discussions of HD Radio- the digital commercial broadcasts of FM (88-108MHz) stations. I am interested in purchasing an HD radio capable reciever for my truck, as my stock car radio is old with lights out and the cassete player barely works.
Many FM broadcast stations in my area have a HD Radio simulcast.
HD radio interests me because the digital portion of the signal xmits text data (artist/ song name) recieved by and displayed on the hd radio unit.

Does anyone know if the digital signal transmits farther than the conventional FM signal? How line-of-sight is the signal compared to a conventional broadcast radio FM signal? When in the valley of a small hill, say you lose full stereo reception of a conventional signal but can still hear the station; what would the HD radio digital signal sound like? I understand that digital signals are lossless or no signal at all, with no in-between, but would a slight loss of conventional signal equal a total loss of digital signal?

and does anyone know what frequencies the digital simulcast is on? I suppose that would answer the line-of-sight question as well.

thanks,
Joe
KB1RRG

 

[n5ims]

The HD signal will not travel as far as the normal FM broadcast signal. The song information you're asking about isn't directly ralated to the HD transmissions, but is instead RDS (Radio Data System - Wikipedia, the free encyclopedia), which doesn't require an HD radio to use. While shopping, you may save some money by simply replacing your current radio with one that's RDS capable.

In the US, the broadcast radio HD transmissions use the IBOC system. This system specs out that the receivers will automatically switch between digital IBOC and analog FM (for the main channel only) when signal strength drops to a level where IBOC decoding isn't reliable. If you're listening to the main channel on an HD radio what you'll get is the HD signal when possible, if the signal drops where that's not possible, you get the normal FM stereo broadcast, and if it drops further, you'll get FM mono. If you're listening to one of the extra channels the HD broadcast allows (often called HD2, HD3, ect.) the radio will mute or fall back to the main channel, depending on your specific radio or settings you have on that radio.

 

[joehawth]

great information thank you

 

[bromeo]

I am interested in purchasing an HD radio capable reciever for my truck, as my stock car radio is old with lights out and the cassete player barely works.
Many FM broadcast stations in my area have a HD Radio simulcast.
HD radio interests me because the digital portion of the signal xmits text data (artist/ song name) recieved by and displayed on the hd radio unit.

KB1RRG

I bought a kenwood KDC-HD942U head unit, which has a built in HD tuner, for my car about a year ago, and i have been far from impressed with that feature. Like mentioned earlier, you need to be in a good reception area to get the digital signal, or else the radio drops back to analog. The problem is even when you get the digital signal, most of the time the digital channels are very compressed (with noticeable lower sound quality) and many stations run banner ads on their text fields instead of title/artist data. Another observation is the time synchronization of the analog and the digital simulacast; many times there is a lag between themm, and if you are in a marginal reception area, the analog/digital switching can be very annoying. There are not too many choices when it comes to HD radio decks too, unless you want to buy $150 proprietary add-on tuners. You may want to consider getting a deck with RDS (radio data system) ability. They are still analog tuners but they get text information (such as title/artist fields) that you are looking for, and many good non-HD radio decks have this featuer built into them without the added cost.

Anyway just my $.02.