WBZ (AM) IBOC Off!

[Uncle Kaimbridge]

I’m surprised no one jumped on it yet, but WBZ-1.030’s IBOC has been off since sometime Wednesday night (before 11pm)!

 

[N1WVQ]

Hmm, if it's still off, I should check my A.M. stereo radio to see if they're on their backup tx (which is stereo). Any A.M. IBOC that's off is good news!

 

[Uncle Kaimbridge]

Hmm, if it's still off, I should check my A.M. stereo radio to see if they're on their backup tx (which is stereo). Any A.M. IBOC that's off is good news!

I haven’t noticed any change in signal strength (either at South Station or up here on the North Shore), as is usually the case when they’re using their Brighton backup xmtr (such as when they’re painting the Hull sticks).
I remember reading either here or on another board/list that some stations have to shut the 'BOC off for a few days to upgrade its software.

 

[Tom Wells]

Best wishes for a speedy recovery.
The hiss hangs around in the aura of an AM station that has used iboc for weeks, we can't declare
the patient to be in remission until perhaps 6 months passes.

HD AM is a fungal disease, it doesn't repond to antibiotics.
There are even those who claim that instead of trying to "cure" the hiss, it is deserving of recognition as a new life-form.

 

[Laurence Glavin]

Best wishes for a speedy recovery.
The hiss hangs around in the aura of an AM station that has used iboc for weeks, we can't declare
the patient to be in remission until perhaps 6 months passes.

HD AM is a fungal disease, it doesn't repond to antibiotics.
There are even those who claim that instead of trying to "cure" the hiss, it is deserving of recognition as a new life-form.

Eukaryotic or prokaryotic?

 

[JIBGUY]

Tech Question: Is an AM station's analog signal intensity lowered when it is using IBLOC? - About 10 days ago, up here in Bath, Maine, I measured WBZ's signal when IBLOC was on, and it was only about 1/3rd of what it should be. In measuring other stations, they were nearly as they should be, so it's not my field-intensity meter being wacky. I should pull out the meter again and see what it is now....

 

[DanStrassberg]

Tech Question: Is an AM station's analog signal intensity lowered when it is using IBLOC? - About 10 days ago, up here in Bath, Maine, I measured WBZ's signal when IBLOC was on, and it was only about 1/3rd of what it should be. In measuring other stations, they were nearly as they should be, so it's not my field-intensity meter being wacky. I should pull out the meter again and see what it is now....

The only effects on the analog signal that I've ever heard about are the limitation on analog audio bandwidth (to 4750 Hz, which I assume to be the -3-dB bandwidth, but I could be wrong) and the proscription against greater than 100% modulation on NEGATIVE peaks. IBOC or no, no AM should be exceeding 100% modulation on negative peaks. It causes serious audio distortion and splatter. 125% modulation is allowed on positive peaks.

When you took your FIM readings, WBZ might have been in the early stages of implementing that (newly approved by the FCC but widely used for several years in Europe and Asia) technique that allows AMs to reduce their carrier level during periods of low modulation and raise it during periods of high modulation. This technique has at least one name, but I can't remember it. I do know that the FCC requires each station that wants to use this technique to apply for and be granted a waiver, but I don't know which section of the FCC rules must be waived. IIRC, this technique is not incompatible with IBOC, but I don't think there is any published data on what happens to IBOC if the technique is used in combination with IBOC. ISTR several engineers saying the results would not be pretty. If there are negative effects on IBOC, I would expect iBiquity to come up with a "solution," but I wonder whether such a solution would be cost effective both in terms of initial cost and the new technique's alleged savings on the station's power bill.

 

[aaronread]

I haven’t noticed any change in signal strength (either at South Station or up here on the North Shore), as is usually the case when they’re using their Brighton backup xmtr (such as when they’re painting the Hull sticks).
I remember reading either here or on another board/list that some stations have to shut the 'BOC off for a few days to upgrade its software.

Unless things have radically changed in the last five or six years, WBZ AM has two backups. There's one in Hull, meaning there are two transmitters there: the IBOC-equipped primary, and an AM stereo-equipped secondary. Then there's the "tertiary" backup at the studio site in Allston.

When you took your FIM readings, WBZ might have been in the early stages of implementing that (newly approved by the FCC but widely used for several years in Europe and Asia) technique that allows AMs to reduce their carrier level during periods of low modulation and raise it during periods of high modulation

There's been a lot of discussions about this over the years on the PUBtech listserv; several AM stations in Alaska have been the driving force behind this, since many of them are in very remote locations and have to generate their own electricity. When diesel fuel is about eight bucks a gallon (it ain't cheap to move stuff around in Alaska!) and you need it to run a generator 24/7, then ANY savings in electricity can have a significant return on investment. Especially for news/talk stations. It's a clever bit of engineering.

 

[iyiyi]

With Alaskan electric/fuel rates in the stratosphere, one might have figured Alaska's radio stations would have embraced and gone 100% IBOC ten years ago!

A 50,000 watt AM outputs a 50kw carrier at all times. At 100% modulation, a 50kw AM outputs 75kw, 50 kw carrier plus 25kw as sidebands. An FM transmitter with a 20kw transmitter power output provides a 20kw carrier out regardless of modulation levels. A 50kw Digital TV transmitter outputs zero watts as a carrier.

There is zero carrier with pure IBOC.

At least they are paying royally for their myopic views of technical progress. Also, reduced carrier modulation is recommended only for 25kw or higher because any ROI on lesser powers just ain't worth it.

-

 

[Tom Wells]

Even in full digital modes, a wee tiny carrier must remain in order to have somthing to reference TO.

Bits do not exist in a vaccum, else they mean nothing at all.

 

[mgpt6]

as of tonight , WBZ's IBOC is still off. Got KDKA 1020 AM on my car radio tonight.

 

[jlehmann]

Unless things have radically changed in the last five or six years, WBZ AM has two backups. There's one in Hull, meaning there are two transmitters there: the IBOC-equipped primary, and an AM stereo-equipped secondary. Then there's the "tertiary" backup at the studio site in Allston.

The AM Stereo backup transmitter is gone, unfortunately. There is still at least one backup TX there in Hull though.

 

[fybush]

Hull has a pair of alternate mains. When I was there, it was a pair of MW50s; now I believe it's either a DX50 and a 3DX50 or a pair of 3DX50s. And AFAIK, the DX10 backup is still in place at the Allston studios; whether it's still set up for stereo, I couldn't say.

 

[necrat123]

Hull has a pair of alternate mains. When I was there, it was a pair of MW50s; now I believe it's either a DX50 and a 3DX50 or a pair of 3DX50s. And AFAIK, the DX10 backup is still in place at the Allston studios; whether it's still set up for stereo, I couldn't say.

They have a DX50 and a 3DX50.

 

[Tom Wells]

Last night, both KDKA and WHO were sounding good in Chicago.

WBZ itself was crisp and clear unlike it has sounded for years.

1050 was mush but KYW 1060 was also fine and clear.

With WSCR 670 clear of iboc, I have been able to enjoy WSM quite a bit this winter, even
after 7AM on the way home from work.

 

[KB1OKL]

I expected this, WTAG's noisemaker was off for a few weeks a couple of weeks ago, I too think it's some software change. WBZ will be whooshing soon. It seems that these iBlock AMers follow each other, the shutting off and turning back on the RF pollution seems to be staggered, I'm sure that's coordinated by ibiquity, can't have people thinking that IBOC is a failure right?

 

[Uncle Kaimbridge]

I’m surprised no one jumped on it yet, but WBZ-1.030’s IBOC has been off since sometime Wednesday night (before 11pm)!

It’s Baaaaaaaaaaaaaaaack! :'(
Came back sometime between 9:30am-1:00pm yesterday. :'( :'(

BTW, on a totally different note, 1.120-WBNW has been FUBAR with a double feed all night and this morning (Bloomberg and local/actual).

 

[HD_Ready]

I’m surprised no one jumped on it yet, but WBZ-1.030’s IBOC has been off since sometime Wednesday night (before 11pm)!

It’s Baaaaaaaaaaaaaaaack! :'(
Came back sometime between 9:30am-1:00pm yesterday. :'( :'(

BTW, on a totally different note, 1.120-WBNW has been FUBAR with a double feed all night and this morning (Bloomberg and local/actual).

Mow I can't wait to drive in to work! I might leave early so I can get my fix. ;D ;D ;D ;D ;D ;D ;D

 

[aerie]

I'm kind of at the borderline for WSRS's HD signal, but I notice that has either been off for a week or more or I need to move my antenna. On the other hand, lately I have been able to get WXKS-FM HD occasionally whereas I never could before.

WEEI-FM HD2 funkytown has progressed: they were still ID'ing as WMKK HD2 for a while after the call letter change, but now they ID as "WEEI HD2 Lawrence Boston". Third time will be a charmer I'm sure.

 

[mgpt6]

BZ sounded so much clearer in the car with IBOC off. Does sound a bit better than it did over a month ago. Guess the audio is going higher than before.