Chicago's ESPN Radio AM 1000 Shuts Off the Noise!

[audioguy]

For several days now, every time I happened to tune in, the hiss was gone. I thought perhaps it was a brief equipment outage, but I just checked, and it's still the same story. The audio is crystal clear-- what an improvement!

Does anybody know the story behind this? Is the hiss gone for good?

 

[KB1OKL]

I don't know the story either but have heard about it through some of the BCB DX lists, let's hope this is permanent.

 

[ddsparxx]

I, too, have noticed no IBOC. If it is permanent that would be great. WMVP's reception here in VA is good with a little bit of IBOC noise from NY's WINS 1010.

 

[nd2023]

HD adds a delay. The delay means people won't tune in to the station while at the game or listen to the radio instead of the TV audio.

 

[KB1OKL]

HD adds a delay. The delay means people won't tune in to the station while at the game or listen to the radio instead of the TV audio.

Here is Boston we got bunchs-O-buzzes to contend with. WFAN, WOR, (WINS, KDKA, and WBZ are the triumvirate of hiss), WTIC, the kidney channels. NY is just a big bunch-O-hiss here in MA many nights.

 

[rbrucecarter5]

It may be to get analog coverage back. It is becoming very clear that any AM running IBOC loses a LOT of coverage both day and night. Stations simply cannot afford to lose that coverage because it affects suburbs in their primary listening area. Smart move, especially since sports radio does not need high quality stereo audio.

 

[ajc_trw]

Smart move, especially since sports radio does not need high quality stereo audio.

Even smarter move, especially since AM-HD radio does not provide high quality stereo audio.

Sorry, couldn't resist.

 

[KB1OKL]

Smart move, especially since sports radio does not need high quality stereo audio.

Even smarter move, especially since AM-HD radio does not provide high quality stereo audio.

Sorry, couldn't resist.

You read my mind, when I was still trying out my now dusty HD tuner if I could actually get WBZ in HD it sounded like krap.

 

[scanman1]

WMVP's digital audio has always sounded like crap and their analog audio was ruined by iboc noise, so turning off the iboc was a great idea as they now sound terrific! I really hope it stays off for good.

 

[Len14043]

It may be to get analog coverage back. It is becoming very clear that any AM running IBOC loses a LOT of coverage both day and night. Stations simply cannot afford to lose that coverage because it affects suburbs in their primary listening area. Smart move, especially since sports radio does not need high quality stereo audio.

You made the assertion in many of your posts that AM IBOC reduces the coverage of the analog signal. Do you mean that they lose coverage from their own digital signal or from the hash of a nearby station? If you are asserting that analog coverage is lost due to their own digital signal, I just can't see any evidence of that. AM IBOC is full of problems, but loss of coverage (from their own digital signal) is not one of them. I travel extensively and am familiar with the ranges of most of the large stations. WLS could still be received in Cincinnati and St. Louis during the day, just like in the pre IBOC days. WLW could still be received in most of Illinois and in Erie PA during the day now, as was the case in the pre IBOC days. I could go on and on. WLW is now clipped as you you approach Chicago, but it is due to the hash from WGN, and not WLW's digital signal. In a previous post, you mentioned that the range of AM stations are reduced in Texas due to their IBOC signal. The only way I could believe that is possible is if the laws of physics are different in Texas than in the Midwest. Perhaps, the "loss" could be measured on a spectrum analyzer or power meter, but certainly not on the average listeners' clock radio. You are an engineer and it should be clear to you that the analog signal is the same in terms of power, but is clipped in terms of frequency response.

 

[audioguy]

WLW could still be received in most of Illinois and in Erie PA during the day now, as was the case in the pre IBOC days. I could go on and on. WLW is now clipped as you you approach Chicago, but it is due to the hash from WGN, and not WLW's digital signal.

Umm, not so! WGN has not been broadcasting with IBOC sidebands for months now (thank goodness)!

It has been my experience that IBOC definitely reduces useful range as far as the average radio listener is concerned. The restricted bandwidth imposed by the exciter results in "muddy" sounding audio and causes the signal to lack "punch". I don't know if there is also a restriction on peak positive modulation, but I wouldn't be surprised. And even if you're only a few miles from the transmitter, you're going to hear an annoying "hiss" in the background all the time, especially if you have a decent radio. I'm talking about self-inflicted noise, not garbage from second or third-adjacent channels running IBOC.

All you have to do is compare WBBM to WGN, and you'll hear the difference immediately. And here's another example: WMVP definitely lost ground in the outlying suburbs when they turned IBOC on... now that they've shut it off, their signal is much louder and cleaner. I sure notice the difference over at my summer home in Michigan!

You're kidding yourself if you think stations running IBOC aren't paying for it in lost listeners!

 

[cyberdad]

I've been traveling in my work for 30 years and my observation is 100% the same as Len's. The blowtorches all get out as well as they did before they added the buzzing junk. The few exceptions are the ones that may have neglected their physical plants (KAAY comes to mind as a likely suspect).

 

[Len14043]

WLW could still be received in most of Illinois and in Erie PA during the day now, as was the case in the pre IBOC days. I could go on and on. WLW is now clipped as you you approach Chicago, but it is due to the hash from WGN, and not WLW's digital signal.

Umm, not so! WGN has not been broadcasting with IBOC sidebands for months now (thank goodness)!

It has been my experience that IBOC definitely reduces useful range as far as the average radio listener is concerned. The restricted bandwidth imposed by the exciter results in "muddy" sounding audio and causes the signal to lack "punch". I don't know if there is also a restriction on peak positive modulation, but I wouldn't be surprised. And even if you're only a few miles from the transmitter, you're going to hear an annoying "hiss" in the background all the time, especially if you have a decent radio. I'm talking about self-inflicted noise, not garbage from second or third-adjacent channels running IBOC.

All you have to do is compare WBBM to WGN, and you'll hear the difference immediately. And here's another example: WMVP definitely lost ground in the outlying suburbs when they turned IBOC on... now that they've shut it off, their signal is much louder and cleaner. I sure notice the difference over at my summer home in Michigan!

You're kidding yourself if you think stations running IBOC aren't paying for it in lost listeners!

I had rarely heard hiss on the analog signal from IBOC. The reduction in frequency response can be heard on a full range audio system, but not on your average radio. And again, I do not see any degradation in the range of the stations - none! The only problem I have with AM IBOC is the fact that it doesn't work well. But repeating factually incorrect assertions may make points with most of the anti-IBOC posters on this board, but it doesn't make them true.

 

[Len14043]

Back in about 2006, Clear channel decided to limit the bandwidth to 5000 Hz on all of their AM stations in an effort to clean up the band. As AM IBOC dies on the vine, it would be nice if all of the stations continued to use the reduced bandwidth.

 

[Savage]

Stations operating with HD-AM generally reduce modulation - depending on the antenna system characteristics, sometimes by a considerable degree. The reason is anything approaching 100% negative modulation greatly increases the potential for self-interference.

When you decrease average program loudness by 3dB, it's like chopping the transmitter power in half. So there is a definite consequence to coverage by reducing modulation. That's why AM stations have densely processed their programming for over a generation now. It's about getting the best coverage possible.

The argument about how "there's no hiss" detected on analog AM radios has been thoroughly debunked. On my new 2009 Jeep Patriot radio the two CCU AM stations in town using IBOC exhibit a constant annoying hiss from the IBOC sidebands. I stopped by a sales guy's house a couple of weeks ago and noticed he had a Tivoli PAL radio. You should hear what WHAM and WHTK sound like on THAT radio. They're absolutely unlistenable because of the HD noise. WYSL sounds like an FM station by comparison.

And these are just two examples. Anyone who hasn't read the accounts of analog self-interference in just about every industry publication and engineering blog, is simply engaging in denial.

 

[audioguy]

Back in about 2006, Clear channel decided to limit the bandwidth to 5000 Hz on all of their AM stations in an effort to clean up the band. As AM IBOC dies on the vine, it would be nice if all of the stations continued to use the reduced bandwidth.

Well, I sure hope you are wrong! Sorry, but I can hear the difference between telephone quality audio and a decent AM signal, even if you can't!

I am sorry to report that the noise is back on AM 1000 as of this morning... so apparently it was a short-term outage.

This must be a great technology if you can afford to just shut it off for a few days or weeks at a time and nobody notices... except the ones who are adversely affected by it.

 

[audioguy]

Back in about 2006, Clear channel decided to limit the bandwidth to 5000 Hz on all of their AM stations in an effort to clean up the band. As AM IBOC dies on the vine, it would be nice if all of the stations continued to use the reduced bandwidth.

Incidentally, that was a completely disingenuous move on the part of Clear Channel! They imposed a limit on the audio bandwidth of 5 kHz, stating that the reason is to reduce adjacent channel interference, but then they proceed to transmit digital sidebands on the first and second adjacent channels such that a station broadcasting in IBOC occupies a total of 5 channels. What a bunch of bull!

NO, that is NOT why they did that! They cut the bandwidth because otherwise the audio signal interferes with their digital sidebands.

 

[Savage]

Of course. It's just another in the series of HD Radio lies, implausible arguments and carefully contrived technical deck-stacking (like the "interference? I don't hear no stinkin' interference!" NRSC 'standard.')

It's just stupid. Anyone can hear the difference between 5 kHz and 10 kHz bandpass. All the arguments about "receiver bandwidth" are completely self-serving and false in any event. Receivers may not be very wide in the case of some car radios, but there isn't a notch-filter "cliff" at 5 kHz with NO response above that threshold. The receiver may be down 5 or 7 or 10 dB at, say 7.5 kHz, but the highs are still there. Even an untrained ear can hear how inferior a vaunted 5 kHz Clear Channel modbox sounds in comparison with full NRSC 10 kHz.

HD-AM: it's over. Turn it off already. At least at night.

 

[rbrucecarter5]

You made the assertion in many of your posts that AM IBOC reduces the coverage of the analog signal. Do you mean that they lose coverage from their own digital signal or from the hash of a nearby station? If you are asserting that analog coverage is lost due to their own digital signal, I just can't see any evidence of that. AM IBOC is full of problems, but loss of coverage (from their own digital signal) is not one of them. I travel extensively and am familiar with the ranges of most of the large stations. WLS could still be received in Cincinnati and St. Louis during the day, just like in the pre IBOC days. WLW could still be received in most of Illinois and in Erie PA during the day now, as was the case in the pre IBOC days. I could go on and on. WLW is now clipped as you you approach Chicago, but it is due to the hash from WGN, and not WLW's digital signal. In a previous post, you mentioned that the range of AM stations are reduced in Texas due to their IBOC signal. The only way I could believe that is possible is if the laws of physics are different in Texas than in the Midwest. Perhaps, the "loss" could be measured on a spectrum analyzer or power meter, but certainly not on the average listeners' clock radio. You are an engineer and it should be clear to you that the analog signal is the same in terms of power, but is clipped in terms of frequency response.

No - a repeatable and noticable loss of coverage. It may well be due to the 3dB reduction another poster mentioned, or perhaps it may be that the AGC circuitry in the AM radios I am using is confused by the extra RF energy on the sidebands and reduces gain to accomodate, or perhaps a combination of both. I discovered another former blowtorch that is now greatly reduced in coverage - WOAI. It used to be almost like a local over Houston, since adding IBOC it is considerably weaker. I can only report my observations, done under carefully controlled circumstances with the identical receivers - the experience with WBAP is a dramatic example. Great coverage before they added IBOC, coverage bad when they ran it, coverage is back to original after they dropped it again. As far as skywave - WBZ a regular and easy catch in East Texas, not there at all after the conversion.

Another factor I could almost believe is that the tower sites have to be modified in some cases to accomodate the IBOC sidebands and deliver flat phase over the broadcast spectrum of the station. But - the experience with WBAP proves that at least in that one case, it was IBOC, and IBOC alone that was the culprit.

I have another thought - on AM, unlike FM, there is no power increase granted to the station to balance the power lost transmitting IBOC. Perhaps the digital sidebands are robbing power from the analog signal - big time.

I have no idea why you observe no coverage decrease on the stations you mention. Of course the laws of Physics don't change, so it is a mystery to me. But my experience is that IBOC ALWAYS is detrimental to the analog coverage. Ironically, I can easily hear the IBOC sidebands of stations 1000 miles away in the daytime - long after the analog modulation is completely gone from distant stations. So perhaps something inherent to the IBOC transmittion process favors sidebands over analog modulation. Certainly the very loud nature of the sidebands gives them a robustness that astonished me. It also means that if digital only is ever implemented, there is a chance of coverage unheard of by today's standards.

Challenge my observations and integrity if you must, but I can only report what I observe in carefully controlled experiments - and my results differ from yours. I'm certainly not challenging your observations and integrity - and ask the same courtesy from you. There is an experimental difference we cannot account for easily. Other observers have noted the same thing I have, I think attention should be paid to the issue by Ibiquity if they have any hope of getting the AM system working properly.

 

[Len14043]

Challenge my observations and integrity if you must, but I can only report what I observe in carefully controlled experiments - and my results differ from yours. I'm certainly not challenging your observations and integrity - and ask the same courtesy from you. There is an experimental difference we cannot account for easily. Other observers have noted the same thing I have, I think attention should be paid to the issue by Ibiquity if they have any hope of getting the AM system working properly.

While traveling the same routes over several decades, I am familiar with the range om most of the big stations to the milepost. For instance, while listening to Rush Limbaugh, I know I'll have to change stations to continue listening to him when reaching a certain exit, rest area, etc. This did not change after the implementation of IBOC - unless the station is hissed upon by an adjacent station with IBOC. You, Savage and others here are correct in that the audio quality is degraded due to the 5 khz, the system is flawed in terms of digital coverage, and the adjacent channel interference can be horrific, i.e WBZ and WYSL. But in terms of reduced range, I just don't see it.

As far as Ibiquity getting the system to work properly, I don't believe that possible. As I stated in other posts, if digital is something we should strive for on the AM band, it should be a system where analog and digital are either on separate bands, or on different parts of the AM band.