Sometime ago I posted a thread which outlined interference on 900 WNMB in North Myrtle Beach, South Carolina, at night. It was like a hiss or a "white noise" underneath our carrier. Some of you suggested it could be HD interference from an adjacent channel or perhaps a co-channel. Here's an update. Since WLS turned off IBOC at night, our signal at WNMB has been crystal clear. No hiss, no noise. Now, I cannot totally document that this is IBOC related, but is sure does seem to have a relation. It will be interesting to see if the noise comes back if and when WLS should resume nighttime IBOC. I do appreciate WLS and its parent company recognizing there could be a problem and them having taken their action to look further into the situation.
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No WLS IBOC, no interference on WNMB
- Thread starter wnmb
- Start date
Martin Stabbert at Citadel has nixed any nighttime HD on WLS or any other former ABC AMs "until iBiquity addresses the adjacent-channel interference problems," which is a polite litigation-proof way for his company to say to iBiquity, "stuff your stupid system." Everyone knows the HD-AM adjacent-channel problem can't be "fixed." It's inherent within the IBOC system.
So WLS is likely to be IBOC-free at night until "iBiquity fixes the interference" or until flocks of redwing blackbirds start spontaneously flying from your left nostril, whichever occurs first. Congratulations - I envy your good fortune to have a Citadel station as your first-adjacent. I've got one run by CBS' Glynn Walden, the "father of IBOC," so we're gonna have to fight. As a first salvo, we filed our formal 50-plus page FCC complaint last week.
I noted that WCBS, two channels from you guys, had their IBOC off last night.
So WLS is likely to be IBOC-free at night until "iBiquity fixes the interference" or until flocks of redwing blackbirds start spontaneously flying from your left nostril, whichever occurs first. Congratulations - I envy your good fortune to have a Citadel station as your first-adjacent. I've got one run by CBS' Glynn Walden, the "father of IBOC," so we're gonna have to fight. As a first salvo, we filed our formal 50-plus page FCC complaint last week.
I noted that WCBS, two channels from you guys, had their IBOC off last night.
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Bob Young
Guest
I used to get their noisy hiss here in MA before they shut it down. The worst ones here are WOR, WFAN and WBZ (when they are testing it) others take their turn ruining the band nightly, depends on propagation. I was trying to listen to WSM a few nights ago which comes in fine almost nightly here and WFAN's hiss was right on top of them. I have very good receivers with an antenna phasing system so I am able to cut them down but it takes constant adjustments to keep WFAN down. The average person without my stuff is SOL when it comes to trying to listen to a station that is next to an iBlock station. I heard the FCC was going to allow spark transmitters again for the AM band. The spark transmitter alliance donated a lot of money to the people who are in power in Washington the past few years. ;D
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Mike Walker
Guest
You can "guarantee" it, The Dude? Now that's scientific!
A betting man might think it a safe bet that WLS's IBOC was the cause. The circumstantial evidence certainly points in that direction. But the only way to "guarantee it" would be to have someone at WLS cycle the IBOC on and off, while monitoring at WNMB. Since that wasn't done, nobody can "guarantee" anything.
This is an engineering problem...a scientific problem. Saying you "guarantee it" is like the rooster beliving that because the sun rises every morning after he crows, he caused it.
My dog poops in the backyard. Porter Wagoner dies. Did my dog kill poor Porter? If we're going to be taken seriously here, we should think carefully about "guaranteeing" things which in fact we have no proof of!
A betting man might think it a safe bet that WLS's IBOC was the cause. The circumstantial evidence certainly points in that direction. But the only way to "guarantee it" would be to have someone at WLS cycle the IBOC on and off, while monitoring at WNMB. Since that wasn't done, nobody can "guarantee" anything.
This is an engineering problem...a scientific problem. Saying you "guarantee it" is like the rooster beliving that because the sun rises every morning after he crows, he caused it.
My dog poops in the backyard. Porter Wagoner dies. Did my dog kill poor Porter? If we're going to be taken seriously here, we should think carefully about "guaranteeing" things which in fact we have no proof of!
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Radioman100
Guest
Mike Walker said:
I wouldn't worry too much about that. The chances that anyone takes this forum for an authoritative source of IBOC news are just about nil.
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rbrucecarter5
Guest
Mike Walker said:
With a very limited number of stations running IBOC at night, it is pretty clear who the culprits are! And IBOC sidebands are VERY robust. I have been out in the middle of nowhere in the West, where there is virtually no AM reception at all - and I can hear IBOC sideband pairs from close to 1000 miles away - NO special antenna! That is daytime. At night, I have heard sideband pairs over LOCAL stations, and sideband pairs from stations whose analog signal I cannot receive, like WOR. One really dramatic example of how strong these sidebands are - daytime - I can actually null the analog portion of local IBOC AM stations, to the point where I can hear stations hundreds of miles distant on the same frequency. Phoenix on 620, who knows what Mexican on 570 - clear enough to ID Phoenix and the Mexican if I spoke a foreign language. But - even though the analog is completely nulled, the IBOC sidebands do NOT null! They are almost as prevalent as the are out of the null.
All this is pointing to one conclusion - we need to re-allocate part of the AM band for ALL DIGITAL transmission, let stations go for the all digital mode and keep analog elsewhere on the band like they did for TV. The all digital mode is probably much more robust than the hybrid - and offers a real chance for coverage unheard of with the analog system. Especially if digital is operated full power instead of low power. I think daytime 1000 mile range would be commonplace for an all digital station, provided the digital algorithms are robust and error correcting. I actually am really enthusiastic about all digital - it is the hybrid mode that is defective because it spills onto adjacents. If all digital would fit in the AM channel without spilling onto adjacents - I think they are on to something.
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WCWalker
Guest
Actually, they should continue to try to revive the old Motorla CQUAM format. Some stations still run it.
I recall listening to WDRC AM 1360 in Hartford on my Carver TX 11a Tuner and was amazed at how rich and natural their stereo signal sounded. It blew FM away!
I recall listening to WDRC AM 1360 in Hartford on my Carver TX 11a Tuner and was amazed at how rich and natural their stereo signal sounded. It blew FM away!
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Mike Walker
Guest
While you're right William, that ship (C-Quam) has sailed. Once stations "rip it out" of the rack, they're not going back. Sad, because (ironically) there are tons of AM Stereo radios out there now (they're known as "HD Radios").
If AM HD doesn't "fly", there will in time be another digital solution for AM stations. Don't look for any resurgance in analog engineering, or moves toward the implementation of any analog mode other than mono on AM. It just ain't gonna' happen. Again sad, because the radios we all hoped for (those of us who worked at AM stereo stations, anyhow) are now out there!
If AM HD doesn't "fly", there will in time be another digital solution for AM stations. Don't look for any resurgance in analog engineering, or moves toward the implementation of any analog mode other than mono on AM. It just ain't gonna' happen. Again sad, because the radios we all hoped for (those of us who worked at AM stereo stations, anyhow) are now out there!
Mike, I disagree with you (a little!). WNMB broadcasts in AM Stereo (c-quam). We hear from listeners almost every day who take the time to let us know they are hearing the fantastic stereo. Any AM station not utilizing AM Stereo today is missing the boat. I have two HD radios at my home. One is the Accurian and the the other is a new Sangean. Both decode and play AM Stereo (although the frequency response is not as good as I would hope for.) The really good news is that there of tons of AM full fidelity stereo radios out there in Ford and Chrysler products. Yesterday, I bought a Mercury Mountaineer SUV. It has a premium sound and our station sounds so good it is just unbelievable (I am referring to tech side, since programming is subjective). I would challenge anyone to listen to the AM stereo on it and dare say FM is as good or better.
My fellow AM broadcasters who want to survive and prosper need to invest in AM stereo and promote the heck out of it. It is the only viable option for right now. IBOC is not going to do it for AM.
My fellow AM broadcasters who want to survive and prosper need to invest in AM stereo and promote the heck out of it. It is the only viable option for right now. IBOC is not going to do it for AM.
Bill, would that be a new or pre-owned Mountaineer? Who is the manufacture on the premium package? It's about time to shop for another car and I really hate the thought of purchasing another vehicle as I have a '95 Chrysler product with a premium Infinity package (Alpine) that has an excellent AM stereo side to it. The next vehicle I purchase must have a "wideband" AM side to the radio and from what I understanding on this board is that many of the stock radio manufactures have hacked away at the AM bandwidth (and, of course, few are offering AM stereo as an option).
The FCC 'missed the boat' with 99-325.
The FCC should have mandated that every new radio that offered HD-FM had to have an AM section with DSP, noise suppression, C-Quam stereo decoding and meet AMAX frequency response standards.
In fact, I did just that, I suggested that "enhanced AM" should be mandated on the HD-FM radios, but to no avail as my docket was 'dismissed'.
The FCC should have mandated that every new radio that offered HD-FM had to have an AM section with DSP, noise suppression, C-Quam stereo decoding and meet AMAX frequency response standards.
In fact, I did just that, I suggested that "enhanced AM" should be mandated on the HD-FM radios, but to no avail as my docket was 'dismissed'.
The Mercury is a 2005. The radio is the Audiophile Satellite Ready unit. FM Stereo/ AM Stereo/ sat input and 6 disc cd player. Fidelity is awesome. When the AM stereo pilot hits and the radio goes wide it is like a symphony hall opened up. It is the best factory auto radio I have ever heard.
RememberWHEN said:
Listening to AM HD Radio stations in wideband mode on my GE SuperRadio III is almost painful. Why would radio manufacturers make more wideband radios as long as broadcasters claim the future of AM depends on the success of HD Radio and continue to try to push this destructive technology?
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Mike Walker
Guest
Finally a point by Supercaster I can agree with! IF more AM stations adopt HD, then radios with broadband analog sections ARE a truly bad idea. The sad thing is, an increase in the power level of the digital signal may be necessary in order to get decent HD coverage. After all, EVERYONE is reporting poorer digital than analog coverage, and reports of signals that don't cover the city limits, let alone the entire metro are common. Is a solution REALLY possible on the AM side?
Now on FM, the technology works quite well, and at least in my area, is providing some VERY interesting alternative programming, not available without HD (24 hour classical, country oldies, rock other than the same old "safe" soungs, etc.) Hell, the 24 hour classical HD2 stream from WFDD actually has live humans (if by network).
Now on FM, the technology works quite well, and at least in my area, is providing some VERY interesting alternative programming, not available without HD (24 hour classical, country oldies, rock other than the same old "safe" soungs, etc.) Hell, the 24 hour classical HD2 stream from WFDD actually has live humans (if by network).
Mike Walker said:
Keep in mind that today's AM radios aren't broadband because of audio fidelity concerns. They're broadband because the manufacturers want to cut back on component count and cost, so they leave out filters, coils and other essential things that would make a radio tune and track properly across the band.
I've seen modern AM radios that have ONE IF can in them. If that. You turn them on and try to tune in something and it's maybe two or three stations all on three or four different spots on the dial.
I also noticed last night that 890 WLS was transmitting C-Quam AM Stereo with full stereo separation and audio bandwidth. Unfortunately, 880 WCBS does a number of them when they keep their IBOC on at night.
Last night I heard a rising and falling hash on WLS that I have never heard before. It turns out that Newsradio 880 was booming into Illinois, strong enough to show the WCBS HD on my Sangean HDR-1 display several times when I tuned to 880.
I am 19 miles away from WLS -- close enough that back when WLS was running IBOC, WCBS was totally obliterated, as was a Canadian station on 900. The Sangean's loop antenna is "mildly" directional but not enough to totally null-out the weak WCBS hash in the background on WLS.
It doesn't surprise me at all that IBOC on WLS was causing such trouble for WNMB!
I am 19 miles away from WLS -- close enough that back when WLS was running IBOC, WCBS was totally obliterated, as was a Canadian station on 900. The Sangean's loop antenna is "mildly" directional but not enough to totally null-out the weak WCBS hash in the background on WLS.
It doesn't surprise me at all that IBOC on WLS was causing such trouble for WNMB!
Philip J. Smith said:
19 miles is definitely within the NIF contour for Chicago's AM 89. I wonder what their engineer would say if you told him what you experienced...... 8)
StephanieNYC said:
It amazes me that a NYC station operating IBOC at all of 500 watts or so is causing such strong interference to a radio station which is over 1,000 miles away. I'm 25 miles from the city and I can't hear any of the out of town IBOC stations on any of my analog radios and none of them cause any interference to the locals here in NYC. WBZ runs Iboc and yet I have no trouble with KDKA or even WHO (if I can null out WEPNs splash) WGY which runs IBOC on 810 causes no interference to neighbor WNYC on 820 Khz. The laws of physics must be different here in NY than elsewhere.I can no longer DX WSM, but it has been barely audible for 30 years or more with local WFAN next door. As far as IDing distant IBOC stations, my best has been WPHT from Philadelphia once, but so far with the included loops I can not receive any IBOC stations after dark and none of them have increased the interference I hear at my house.
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