good old tuners going obsolete

I agree with Armstod (Armstrad made some pretty good tuners in the UK, BTW), but I believe that commerce will play an important role. Radio stations can barely hold on to listeners as it is, it would seem that they would be reluctant to diminish their listener base, and hence income stream, when the gear to continue to cater to it is already there and paid for.

hd radio does not stand for "hi definition", it stands for "hybrid digital". with resolution less than that of mp3, it certainly isn't anything resembling high resolution audio. and, its sideband artifacts can really screw up adjacent fm channels.

while most commercial fm station's audio quality is abysmal, the sound quality of a good station broadcast thru a quality tuner will easily rival the best digital & analog rigs. all it takes os for you to have one station you like, to make it worthwhile owning a high quality fm tuner. 89.3 wpfw in washington, dc, is all it takes for me. and, no, conventional fm isn't going anywhere any time soon. the fact is, that hd radio is expensive technology to implement, & it doesn't really offer most stations any worthwhile adwantages over standard fm. reception - especially in the car - is not any better, & in many cases, (especially in the car), it is worse.

ymmv,

doug s.

Just so where are all on the same page ( and I could go into far greater detail but i don't want to bore you )

QAM-Quadrature amplitude modulation

is a modulation scheme which conveys data by changing (modulating) the amplitude of two carrier waves. These two waves, usually sinusoids, are out of phase with each other by 90° and are thus called quadrature carriers—hence the name of the scheme.

Unlike the analog “Sinusoid” or " sine wave which curves up and down much like alternating current does. And in case you wanted to know- " The television signal is made up of two parts, both related to each other by the frequency of the carrier signal. The image signal is amplitude modulated and occupies about three fourth of the total bandwidth (which is usually 6 megahertz) the audio component of the TV signal is frequency modulated and has a frequency in the range of the upper quarter of the band frequency range. "

In QAM, the constellation points are usually arranged in a square grid with equal vertical and horizontal spacing, although other configurations are possible. However it appears that in America we have chosen the " square gird " In the same space that one could place a 6 Megahertz analog signal, we can now place 12 digital channels in a 256 QAM pattern. This makes digital signal very desirable.

Unlike analog signal that can bleed over into an adjacent channel, and cause " co-channeling " Digital will NOT bleed over at all. The reason should be quite clear. With analog the Sinusoid can be distorted more easily ( on your analog radio you know doubt have heard another station bleed through ) when this happens it is possible to get the audio or picture of another tv station over yours. With digital we are not relying on these waves to stay so harmonious. We are relying on a grid to stay square, when it does not there is nothing left to bleed. You will also find many adjacent channels are gone as well. To keep our signal pure we simply need to keep the system " air tight " If the system is not air tight then we have what is know as BER ( binary digit error ) When to many errors occur you will experience " jittery audio " and or" tiling " or macro blocking " Most common cause of a system that is not air tight are bad connectors, poorly shielded cable, or low signal. Oh and don't forget when the customer decides he is qualified to do his own wiring, this is a major cause of the problems we find.. Every time I go past Radio Shack I cures those worthless gold plated screw on fittings and that RG59 cable!

Ok back to what I was saying....With analog signal the sound becomes weaker and weaker, the picture becomes grainy or snowy. With digital signal when you have BER it just plain disappears! There is NO bleed over, well at least in my 10+ years as a system-network tech for cable tv. Of course running a 256 QAM is more risky than a 64 QAM signal. But Cable television has got it perfected " as long as it is a air tight system " Anyone with a digital box will have to admit that a digital picture is clearer and more defined than without the box. I expect someday radio will also achieve this.

Sedond,

Your quote

" and, no, conventional fm isn't going anywhere any time soon "

Since you have said it I can take it as gospel? I am wondering if your the president of the FCC?

Kt_88,

Sedond is arguably the foremost tuner guru on Audiogon, and you choose to discount his input? You might want to re-think that approach. How about responding to my post above, where I present clear evidence contrary to your claims? Your 10+ years as a cable TV guy have served you well in that arena as your comments there are spot-on, but you still haven't been able to corroborate your allegations of a radio deadline.

Based on your explanation above, I have no doubt digital radio will have some significant advantages over analog, but that's not why you started this thread.

kt88, is this an audio forum, or a tv forum? what does your post have to do w/fm? i don't care about tv - i don't even own one.

hd radio broadcasts have sideband signal; this is what interferes with adjacent fm channels. and, hd radio compression is more severe than even mp3. lo-fi, imo.

doug s.