BREAKING NEWS! THE REAL REASON WHY WGN HAS DROPPED HD-AM

[8638]

There's nothing absurd about using most AM radios that came after 1927.
They may be limited to 550-1500 khz, but they are in several respects superior to modern types.

I just rebuilt a Stromberg-Carlson console unit that was designed in the mid-'50s. It has selectable AM IF bandwidth with a 10 kHz notch filter to knock down the adjacent channel carrier whistle, and sounds quite full even in narrow bandwidth because those LC IF transformers have reasonably gentle and symmetrical skirts. And there's just something musical about a push-pull 6L6 output stage, especially when the coupling caps have been replaced.

But I should clarify that it sounds its best on stations that don't run IBOC, otherwise signal/noise ratio is noticeably degraded and the audio response cuts off so sharply that I hear no improvement when I switch over to wideband mode -- only more noise, on account of the HISS-OLA scandal.

740 in Toronto puts a great signal into this area in early evening; it's nice to know some AM broadcasters still care about good audio.

Love all this discussion about old gear! As for AM 740, it puts an excellent signal into New Jersey from before sundown on through the night. Great music too!

I'm just a listener, but I find listening to AM stations that run IBOC trying, at best. The narrow analog bandwidth removes any vestige of audio fidelity, and that damned hash kills adjacent channels 20 kHz out. Add that to the electrical noise of LED stop lights, power lines, etc. Makes me yearn for an FM talker around here.

 

[Tom Wells]

It has selectable AM IF bandwidth with a 10 kHz notch filter to knock down the adjacent channel carrier whistle,740 in Toronto puts a great signal into this area in early evening; it's nice to know some AM broadcasters still care about good audio.

Not to throw this thread completely off, but is that 10kc notch in a high-impedance circuit, or is it in the speaker circuit?
I can supply a schem for a passive -42 db 10 kc notch with 2 db insertion loss that is extremely narrow and uses only 4 parts.
It was published in a 1947 Radio News magazine, and I would hope a '50's design would have incorporated this superior method.

AM 740 is truly one of the last audio showcases on AM.
I wish WGN 720 was as crisp. In Chicago WLS still has the edge over all the other AMs for audio quality, especially since WMVP went hissville.

 

[Savage]

Ahh, Stromberg-Carlson....another quality product once made in Rochester, New York (like photographic film, which we also used to make here.) Interestingly I drove past Carlson Road last night and the former SC plant, right next to to Channel 8/31....once Rochester Radio City. SC was licensee of WHAM, and was a pioneer in TV and FM. 98.9 here in town (in its original lowband iteration) was actually the first commercial FM station in the US, "WHFM."

I can't help but wonder how the SC engineers who proudly designed high fidelity audio components, and top-quality radio and TV receivers like Freebird's would have felt about IBOC. After all....even in analog...."There Is Nothing Finer Than A Stromberg-Carlson."

(Go ahead, Clouseau. Take your usual shot at geezers, living in the past. With a smiley face.)

 

[Play Freebird]

Not to throw this thread completely off, but is that 10kc notch in a high-impedance circuit, or is it in the speaker circuit?
I can supply a schem for a passive -42 db 10 kc notch with 2 db insertion loss that is extremely narrow and uses only 4 parts.
It was published in a 1947 Radio News magazine, and I would hope a '50's design would have incorporated this superior method.

It's high-impedance, between the detector and input to the audio amp. Here's the Sams schematic; the notch filter is C35, R34 and the C37 trimmer in series with L23: http://www.audiophool.cjb.net/Schem_A/S-C_SR-406_schem.gif
Note the alternate parallel LC circuit on the right side of the page. Which would you prefer?

There's a sad picture of a rusty SR-406 chassis in a rack mount panel about halfway down the following page. I hope the finder salvaged the Lorenz EM85 magic-eye tube; they're getting scarce. Fortunately, my receiver is in much better condition.

http://www.audiophool.cjb.net/MadeInRoch.html

 

[Savage]

Getting back to the original subject of this thread:

FWIW I note that almost a week has gone by since I invited Mr. Carollo or anyone "in the know" at WGN to confirm or deny that Arbitron PPM interference is the reason the station has dropped HD. (Oh, excuse me. I know we've been told WGN "has not dropped" HD. I meant, "stopped using it.")

In the absence of an unequivocal denial - taken together with the quality of my original source for this story - I think we can assume that the allegations are true.

 

[davideduardo]

In the absence of an unequivocal denial - taken together with the quality of my original source for this story - I think we can assume that the allegations are true.

Analyzing the moves of a company in bankruptcy is always going to be difficult.

 

[clouseau]

I can't help but wonder how the SC engineers who proudly designed high fidelity audio components, and top-quality radio and TV receivers like Freebird's would have felt about IBOC. After all....even in analog...."There Is Nothing Finer Than A Stromberg-Carlson."

(Go ahead, Clouseau. Take your usual shot at geezers, living in the past. With a smiley face.)

No fun made at all, Bob. My continuing point is merely that discussions about high end audio equipment aren't all that relavant in todays radio market, as I'm sure you know. I love some of the older stuff have a great respect for that "Sound of yesteryear". Like you I grew up listening to AM radio. All I would say is that clearly times have changed. And not necessarily for the better.

Clouseau

(This post certified Smily free)

 

[pocket-radio]

Does it really matter why WGN dropped HD-AM? The signal is loud and clear, for whatever the reasons, they considered their HD-AM investment to be a poor asset and pulled the plug.

 

[Savage]

I think the reason matters a lot. If "might be killing your ratings because it interferes with PPM encoding" gets added to the long list of problems with HD Radio, it's a huge disincentive for anyone who remains undecided, to install the thing. There is of course a direct correlation between ratings and revenue.

It would be foolish for anyone to install a highly dubious technical "improvement" which on the one hand, provides no quantifiable benefit for listeners or advertisers and imposes steep installation and licensing costs - and on the other hand, could directly cause an unnecessary loss of revenue. Some might call it "suicidal."

 

[audioguy]

Guys,

I wouldn't get too excited about this. WGN has turned the hiss-o-matic off (and on, and off again) before, just like every other HD radio station. Jim made it clear that this is likely to be a temporary situation. What does that say about the technology when you can afford to turn it off for days or weeks at a time? Meanwhile, AM 1000 has caught the hissies now, meaning that I can no longer listen to the CBC on 990... not that it matters, since they took all the programs I liked off the air.

Lots of press in the latest Radio World about how 2009 is going to be a great year for HD Radio (it's going to come into its own at last, apparently).

 

[Savage]

Funny: I get the opposite impression from Jim Carollo's comments about WGN-HD you do. The way I read his words, they sound like a guy whose station has dropped HD but is struggling mightily to give the appearance they really haven't. Then, after the passage of some time, they'll hope nobody has noticed IBOC hasn't been put back on.

Of course, audioguy, you may have better information than I do. But that's the impression I get.

And then you have my source who confidently told me that problems with PPM Arbitron credit caused by HD is the culprit. I brought this story to the attention of a "major trade publication." They told their radio editor to get right after the story and check it out, so it will be interesting to see what if anything comes out in coming weeks.

 

[KB1OKL]

In the absence of an unequivocal denial - taken together with the quality of my original source for this story - I think we can assume that the allegations are true.

Analyzing the moves of a company in bankruptcy is always going to be difficult.

Perhaps they've decided that WHOOSHBOC costs TOO MUCH money for three listeners.

 

[davideduardo]

Perhaps they've decided that WHOOSHBOC costs TOO MUCH money for three listeners.

Once installed, there is essentially no cost.

 

[davideduardo]

I think the reason matters a lot. If "might be killing your ratings because it interferes with PPM encoding" gets added to the long list of problems with HD Radio, it's a huge disincentive for anyone who remains undecided, to install the thing. There is of course a direct correlation between ratings and revenue.

As mentioned, the ratings were higher in the first months of PPM for WGN than they were in the diary survey before it. However, after the baseball season, GN lost share, which it also did in the diary survey.

If it's about ratings, they have gone up. And I fail to see how HD can interfere with the PPM, which is a microphone based audio system, not an RF system

 

[Tom Wells]

Perhaps they've decided that WHOOSHBOC costs TOO MUCH money for three listeners.

Once installed, there is essentially no cost.

Love ya David, but whoa right there.

I'll agree now with several others who contend that it costs in terms of actual analog field strength for AMs.

If power input remains the same, all modulation products referenced to the carrier "subtract" power from the carrier until at
-100% there's no more carrier. The "RF out" pie is finite, and any pie served up digitally will be just that much less
pie left to be served up in analog. I'm referring to the radiated output, not input power which could be upped to try to compensate,
but as the same radiator is used, the "pie" analogy would still hold. Separate transmitters and antennas for AM might give back
the coverage, unless the same effect occurs when the signals mix in transmission, resulting in the same loss.
My radio school gut knowledge, without consulting a text says you don't get something for nothing.
It is well known that stations running iboc must never run so loud in analog as to hit -100, because the digital will drop when the carrier's out.
So they run the mod down and let the big watts carry it.

It's not a full signal, that's why it sounds like the 1000 watt local on 1340 from 3 counties over on a winter day as a dx signal from our youth.

On the other hand, WGN may have decided it was costing them in listeners lost.

 

[audioguy]

Savage,

I don't have any inside information like you do. But Jim's response to me (and you have a copy of the letter) suggests to me that he thinks HD is the future of AM radio, and that we're just a bunch of old geezers because we don't support it. Nothing could be further from the truth; I love technology when it works (my hobby is now Information Technology), but I deplore junk science.

I would like to take the opportunity, on behalf of radio listeners everywhere, to thank you for all you've done to help expose HD radio for the monopoly-owned, low-fi, digital smog that it is.

 

[davideduardo]

It's not a full signal, that's why it sounds like the 1000 watt local on 1340 from 3 counties over on a winter day as a dx signal from our youth.

On quite a group of HD AMs, we have no feeling or concern that we have lost coverage or loudness.

On the other hand, WGN may have decided it was costing them in listeners lost.

As I said, for the first 5 months of PPM in Chicago, WGN had higher numbers than under the diary... after baseball season, with and without PPM is about the same. Considering that most AMs are on a gradual decline, WGN might say that HD reversed a decade-old trend.

 

[Savage]

Thank you very much, audioguy.

And I'm not gonna quit. 2009 will be a prescient year for HD Radio. I think it will be fascinating to watch.

 

[KB1OKL]

WLW was whooshing all over WOR last night here in Analog MA, great system that IBOC. ;D Encountering a whooshomatic IBOC signal covering up 30 KHz of space while cruising up and down the AM band is like bumping into a skunk at a picnic. At least with a skunk you can get away from the smell. I live 40 miles from WBZ, the only way I can receive it in glorious synthetic IBOC is by spending 5 minutes contorting and tuning my C Crane Twin Coil AM antenna which cost more than I paid for arguably IBOC's best receiver.

 

[clouseau]

WLW was whooshing all over WOR last night here in Analog MA, great system that IBOC.

Of course the fact that WOR doesn't proport to serve your area at night is irrelevant to your point I suppose, right? The continued railing about problems with DX just don't carry any water as far as broadcasters seem to go.

Do you hear ads for Mass. Business on WOR?

Clouseau