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KTRB in HD

H

HHalland

I mailed off to Unitron Electronix out of Covey, NY and purchased a B-stock BA-HD radio..because you see this will be most likely the saving gear to make AM radio back on the big pile again. You can't walk into any electronics places here in SF and get a straight answer from anyone about this. You can't even call a station to ask any questions about it. I got a recording when I called KOII and nobody want to talk about this exciting new radio. Everyone says they are trying to sell the public on this but I think it might be a sham and a fake. Pretty soon everyone will just forget about all this, and either stay with Sirius or just buy an Apple pod anyways.

On my new BA radio in HD I do not hear a good difference in the FM however. Can someone tell me how this operates. Because this was a return it did not come with a book. I e-mailed Boston to ask them, but have not heard back yet. The very few radio stations that are playing HD sound very flat and lifeless. Plus they are not playing anything I would like to hear anyways. For FM this will not work, but when KTRB plays in HD this will be truly stellar. I hear that AM can not play in HD at night. How are we supposed to DX at night in HD? This is a foolish decision especially because of the number of us in the National DX club wo would listen. There are hundreds of us you know.

Thank You
Howard
 
Truly sorry that you are disappointed, but FM HD may sound better when the engineers have learned to do the audio right.
AM HD doesn't work at night due to phase-shifting cancellations from skywave, which destroy the integrity of sidebands.
Certain frequencies ( varying) are lost in a way that gives AM DX the sound that you recognize as a "well traveled signal".
While your ears and brain can decode such "mangled" audio, guess what? The HD has no idea what to do with this incomplete data.
Glad you found a discount way to try this out.

Tell 10 friends about this sham, and why AM stations running HD are now required to sound awful in the analog, along with
the incessant hissing from the AM sideband "flamethrowers".
 
Tom Wells said:
Truly sorry that you are disappointed, but FM HD may sound better when the engineers have learned to do the audio right.
AM HD doesn't work at night due to phase-shifting cancellations from skywave, which destroy the integrity of sidebands.
Certain frequencies ( varying) are lost in a way that gives AM DX the sound that you recognize as a "well traveled signal".
While your ears and brain can decode such "mangled" audio, guess what? The HD has no idea what to do with this incomplete data.
Glad you found a discount way to try this out.

Tell 10 friends about this sham, and why AM stations running HD are now required to sound awful in the analog, along with
the incessant hissing from the AM sideband "flamethrowers".
Click to expand...
It's a scam like HDTV! Remember AM Stereo?
 
HDTV may be some sort of a "scam" but I like watching it much better than the fuzzy shadowed analog.

Anyway, with a few taps on the touch screen of the IBOC exciter any AM station can run 7 kHz audio AND IBOC HD radio. Just not as robust (the ability to withstand first adjacent station interference) without the "secondary" digital carriers on.
 
Tom Wells. Thanks for explaining this to me. I understand the problem with the HD radios not understanding the shifted audio, so that would be what makes them switch back to analogue right? Okay if that is the reason, why didn't broadcasters just tweak thier analog fidelity and make it more HiFi..say to 12kcs? It can be done right? I remember hearing some of the great Canadian radio stations in the mid 70's that were so hifi you would swear you were hearing FM. Would it not have been to everyone's advantage to just keep AM stereo and rise the standard so that they all sounded good, and make the reciever makers make better radios..rather than fooling around with all of the so-called HD Radio stuff? Man-oh-man who wants this? I think it sounds awful, and the rest of the AM radio sounds bad too. Why does Clear Channels put it only to 4.5kcs or whatever it is? Nobody likes the sound and it is driving away listeners. KTRB will not do this. They will put a quality sound out I'll bet.

Howard Halland
thank you
 
Yes, it is possible for the AM to have full fidelity to 12 or even 15 Khz. Unfortunately, 20 years of AM radio production with narrow-IF bandwidths have made a good many people think AM must sound like land-line telephone.
These were produced in response to the ever-worsening man-made interference. Unless one is lucky or has carefully chosen their
homesite, and avoided lamp dimmers, digital cable, etc., they would not be able in many cases to enjoy such fidelity.
In the car, there would be occasional noise, but a better chance at a clear signal a good deal of the time.
And if adjacent channels are strong there would be "monkey chatter".
And the 10khz whistle would need to be notched out for night reception.


A few US AMs experimented with wideband audio in the 70's, with response to 15Khz.
I remember WGAR in Cleaveland, when it was top 40, as one that tested this.
Even in NW Indiana, about 300 miles away, I was shocked at the clarity and upper-end response.
I still hope AM IBOC is just a bump in the road, and sanity will return us to AM stereo and/or wideband AM.
My own pt 15 is relatively flat to 20khz. If I put a FM radio audio source on, and tune 20 khz up, I can hear a 1 khz tone from the 19khz
stereo pilot.

I do add a passive -60 db notch in the speaker circuit for the 10khz whistle, and that alone makes the existing audio sound much more
like FM. I have posted a schematic for this quite while back, and with only 2 capacitors, a 25-ohm rheostat and a hand wound coil, you can completely notch out the whistle with only 2-3 db of insertion loss.

If AM were to take advantage of noise limiting, variable bandwidth, DSP, DNR ( Dymanic Noise Reduction ) by National Semiconductor, there would be little reason to use 50khz bandwidth as AM IBOC does.

Unfortunately the same QRM that impairs AM analog reception largely renders IBOC unusable.
The bandwidth reduction for the analog when HD is applied is really the killer.
Even if it were acceptable to trash the adjacents, there is no justification for making the *very best* hi-fi AM radios sound the worst.
I hope you will voice your feeling to KTRB, as I have to Chicago AM stations running IBOC.
One opinion voiced is usually counted as 1 + 9 more that did not give an opinion, as only one in 10 takes the trouble to say something.

The few Canadian Clears still provide fantastic audio.
 
Tom Wells wrote:

"Truly sorry that you are disappointed, but FM HD may sound better when the engineers have learned to do the audio right"

HD on FM is supposed to sound the same as the analog, but without multi-path. Engineers know this very well, as the Ibiquity folks have insisted on this to make the "blend" between analog and HD as seamless as possible. There is nothing to "learn". However, the HD2 and HD3 are very tricky to do right, and the bandwidth/sample rate is further limited, so this is the area where there is still some learning to be done. With lossy compression, it is never going to equal 20khz analog audio, but it will be a fairly reasonable approximation. YMMV...

And:

"AM HD doesn't work at night due to phase-shifting cancellations from skywave, which destroy the integrity of sidebands"

Uh, OK, that's not true, but the real reason that you can't hear HD on AM stations at night is because it is not authorized to be operating at night, due to adjacent-channel interference caused by the IBOC sidebands. IN tests, HD works OK at night, even in skywave conditions, and is not subject to the phase-cancelling effects you hear with analog AM. The sidebands are actually more robust than the analog, and the HD hangs in there better. But it kills adjacent channel reception, that is the main reason it is not allowed, at least for now.
 
Don Mussell said:
HD on FM is supposed to sound the same as the analog, but without multi-path. Engineers know this very well, as the Ibiquity folks have insisted on this to make the "blend" between analog and HD as seamless as possible. The sidebands are actually more robust than the analog, and the HD hangs in there better. But it kills adjacent channel reception, that is the main reason it is not allowed, at least for now.
Click to expand...


Don! Quit hanging out on these boards! Get back over to KOMY and KSCO in Santa Cruz and get 'em sounding like they oughta! ;D

DJ
 
So, what are YOU doing here too? Get back to selling spots!


Heh, heh. Seriously, MZ must talk to you often!
 
Don Mussell said:
So, what are YOU doing here too? Get back to selling spots!

Heh, heh. Seriously, MZ must talk to you often!
Click to expand...

Errr, umm, errrr, I... well, uh.... hmmm, yeah.

Oooh, look! An airplane!

(Runs away quickly without answering.)
 
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