Please Explain to me...

[SUPERCASTER]

Perhaps someone on this board will be able to answer this question for me.

I don't yet have an HD radio. A few weeks ago I noticed that whenever my local AM
station which carries ESPN switches into day pattern, their audio quality falls off significantly. (It almost sounds as if you are listening over an old-style analog phone line.) The audio goes back to full-quality when they shift back to night pattern. During the day I notice that if I off-tune slightly from their frequency in either direction, I get a strange whirring sound that resembles a dial-up PC modem. Is this station testing in HD, and is that why their analog audio is so lousy during the day? I have emailed their engineering dept. but no one will answer the question.

The symptoms you describe, indicate your local ESPN AM station has IBOC. It may be terminal, unless given proper, professional engineering attention immediately. However, "resistance is futile" once the iBorg collective assimilates the station.
All listener complaints are ignored. Symptoms like "telephone fidelity" and "buzzing adjacent channels" are proclaimed "impossible", attributed to your insanity, overactive imagination, and malicious intent. The problem is not the station, but YOU, because you have not yet been assimilated by the iBorg collective.
Repeat after me:
"There are no complaints about HD radio, and never have been."
"HD radio always offers perfect reception, unlimited range, under all circumstances, and interference is just your overactive imagination, caused by your insane distress over not having been accepted to be absorbed by the iBorg collective".
"HD radio, is ALWAYS perfect radio".
"Resistance is futile".
Of course the FCC requires all licensees to take listener complaints seriously, so making HD complaints disappear, is a violation of FCC rules. No matter, the iBorg have already absorbed the FCC.

Just say no! Tell all HD stations to "buzz off"!

 

[dbdigital]

Perhaps someone on this board will be able to answer this question for me.

I don't yet have an HD radio. A few weeks ago I noticed that whenever my local AM
station which carries ESPN switches into day pattern, their audio quality falls off significantly. (It almost sounds as if you are listening over an old-style analog phone line.) The audio goes back to full-quality when they shift back to night pattern. During the day I notice that if I off-tune slightly from their frequency in either direction, I get a strange whirring sound that resembles a dial-up PC modem. Is this station testing in HD, and is that why their analog audio is so lousy during the day? I have emailed their engineering dept. but no one will answer the question.

The symptoms you describe, indicate your local ESPN AM station has IBOC. It may be terminal, unless given proper, professional engineering attention immediately. However, "resistance is futile" once the iBorg collective assimilates the station.
All listener complaints are ignored. Symptoms like "telephone fidelity" and "buzzing adjacent channels" are proclaimed "impossible", attributed to your insanity, overactive imagination, and malicious intent. The problem is not the station, but YOU, because you have not yet been assimilated by the iBorg collective.
Repeat after me:
"There are no complaints about HD radio, and never have been."
"HD radio always offers perfect reception, unlimited range, under all circumstances, and interference is just your overactive imagination, caused by your insane distress over not having been accepted to be absorbed by the iBorg collective".
"HD radio, is ALWAYS perfect radio".
"Resistance is futile".
Of course the FCC requires all licensees to take listener complaints seriously, so making HD complaints disappear, is a violation of FCC rules. No matter, the iBorg have already absorbed the FCC.

Just say no! Tell all HD stations to "buzz off"!

Yup, technical problems aside, HD Radio "stinks" of Clear Channel and the other greasy radio conglomerates; car salesmen in the broadcasting industry (which, in Clear Channel's case, is literally true).

db

 

[MotoMuzak]

Supercaster~

Ya think Locutus himself might be running part of it? Maybe in an (sort-of anachronistic) alliance between the IBorg collective and Species 8472, perhaps? ;o)

 

[tomservo]

If you look on www.nrscstandard.com you will find a whole report on what typical AM radios do with their audio response. They also found out that more people like the 5 - 6kHz range when listening to AM radio. Now that will depend on the program material and all, but to me as an engineer that came as a surprise.

It is a very eye opening report!

I'd read it if the link worked. ???

Maybe people say they prefer the 5-6 kHz range because they don't know AM can do better.

there is no need to limit the bandwidth of the AM analog signal to 5kHz. As a matter of fact, on the iBiquity software (on the exciter) you can set the analog for 8kHz or 5kHz bandwidth.

Does anyone know of a station that's done this? Early on, an engineer told me that it was 5 kHz only. 8 kHz would be a little better on the ears; would it affect the bitrate of the digital signal?

Any noise on the analog signal is due to non-linearities of either the antenna system (more than likely) or the tranmsitter (less likely). And yes I have heard a number of AM stations have some noise on their analog signal. In ALL instances, the engineer was working very hard to get the linearity corrected.

There must be a lot of scrambling nerve-wracked engineers around, because I've yet to hear an AM station doing IBOC that didn't have noticeable noise over the analog signal. Some are not too annoying (WREC, Memphis) but most are so obvious and grating that it sounds like something's wrong on their end (WSPZ, WSCR, WGN, WCGO? (or was it WVON?), WLGD, KLDZ, KDDZ, KLLT, KLVZ, KLZ, KOA, KPOF, WXJC, WDIA... And that's just what I can remember off the top of my head as sounding like utter crap.)

 

[SUPERCASTER]

If you look on www.nrscstandard.com you will find a whole report on what typical AM radios do with their audio response. They also found out that more people like the 5 - 6kHz range when listening to AM radio. Now that will depend on the program material and all, but to me as an engineer that came as a surprise.

It is a very eye opening report!

I'd read it if the link worked. ???

Maybe people say they prefer the 5-6 kHz range because they don't know AM can do better.

there is no need to limit the bandwidth of the AM analog signal to 5kHz. As a matter of fact, on the iBiquity software (on the exciter) you can set the analog for 8kHz or 5kHz bandwidth.

Does anyone know of a station that's done this? Early on, an engineer told me that it was 5 kHz only. 8 kHz would be a little better on the ears; would it affect the bitrate of the digital signal?

Any noise on the analog signal is due to non-linearities of either the antenna system (more than likely) or the tranmsitter (less likely). And yes I have heard a number of AM stations have some noise on their analog signal. In ALL instances, the engineer was working very hard to get the linearity corrected.

There must be a lot of scrambling nerve-wracked engineers around, because I've yet to hear an AM station doing IBOC that didn't have noticeable noise over the analog signal. Some are not too annoying (WREC, Memphis) but most are so obvious and grating that it sounds like something's wrong on their end (WSPZ, WSCR, WGN, WCGO? (or was it WVON?), WLGD, KLDZ, KDDZ, KLLT, KLVZ, KLZ, KOA, KPOF, WXJC, WDIA... And that's just what I can remember off the top of my head as sounding like utter crap.)

You are right, Zach.
The only study I know of that even mentioned people preferred lower frequency response, was a study commissioned by iBiquity, to justify their own defective broadcasting system.
If people prefer lower fidelity, where does that leave HD radio, CD's or even FM?
Clearly that is not the case, and a rigged study, commissioned by an interested party, does not prove otherwise.

 

[amfmsw]

Zack...WPEN Philadelphia dropped its' analog to 5Kc upper limit. It was in an Oldies Format at the time, and it was unlistenable for more than 20 minutes. Imagine a standard table radio playing music on AM. Now, imagine throwing a heavy wool blanket over it. That's what it sounded like.

 

[Tom Wells]

Regarding AM high frequency response....
If people prefer all high frequencies cut off at 5 kc, why do tweeters exist?
Or why did standard design always previously accept that response needed to go up to 10kc?
And if true, then why didn't ibiquity design both AM and FM HD to a 5kc upper limit?

This is like saying people "prefer" to keep sunglasses on at all times, when of course, there is no justification for such a statement.
There are "some" circumstances where it is preferable, as in trying to receive a weak signal next to a powerful adjacent.
But then this a special case for a communications receiver, where I would not expect high frequency response.
Currently, AMs with HD are cutting so much off of the high end that intelligibility suffers.
It is difficult to distinguish words with the letters S, F and T, especially with the IBOC hiss obscuring what slight difference is left.

 

[Mike Walker]

I'm in total agreement. HD is potentially great technology, but it isn't worth sacrificing your current audience for. They are, after all, your bridge to whatever transmission modes the future holds. Run them off with God-awful audio now, and you've "burned your bridge(s)". Any AM that thinks they can afford to lose ANY current listeners in orfer to gain future ones with HD is operated by people who belong on the mental ward!

Radio is about PROGRAMMING. It's "show biz". First a certain level of audio quality must be established so that one can "listen through" the hardware to enjoy the program. Beyond that basic level of quality, everything else is gravy. Now gravy is NICE, but it ain't a meal. FM HD=very nice gravy. AM HD=LUMPY, cold gravy...not very tasty. Lunch anyone?

 

[tomservo]

Oops, I should have clairified one of my previous questions. What I meant to ask was whether or not any station doing IBOC on AM has opted for the supposed 8 kHz analog cutoff instead of 5 kHz. So far, all I've heard are the 5 kHz cutoffs on IBOC on AM stations.

 

[FreddyE1977]

Thanks Supercaster and dbdigital. The station is not Clear Channel, it is the Disney O&O ESPN station in Pittsburgh. Fidelity is so bad I can barely stand to listen...and it's an all-talk format! I can just imagine what stations playing music must sound like! They sound SO BAD compared to any other AM station on the dial (including rimshotting tin-whistles) that they are now at a distinct competitive disadvantage. I live virtually in the shadow of their tower, so no excuses about comet trails and compact flourescent bulbs will be accepted. (Actually have not gotten even a weak excuse in reply to inquiries yet).