AM HD TURNOFF PACE ACCELERATES

[spunker88]

Before I retired and moved to Midland, Michigan, I lived in Tampa Bay. I just couldn't listen to 970WFLA. The constant HISSSSSS from their IBOC signal was too annoying.
Analog and digital do not co-exist well on the same RF carrier.

Maybe your receiver has its AM bandwidth too large for a station broadcasting in HD. These stations reduce the bandwidth of their analog signal to make room for the HD, even though it still spills over the sidebands. But if your receiver has an AM bandwidth too wide then its probably picking up some of the IBOC along with the analog signal. Lowering the bandwidth should help unless you can't adjust it on this model. Makes you wonder why they won't allow wide band AM stereo broadcasts that would put out splatter but actually sound good and not mess up older receivers.

 

[badjef]

Before I retired and moved to Midland, Michigan, I lived in Tampa Bay. I just couldn't listen to 970WFLA. The constant HISSSSSS from their IBOC signal was too annoying.
Analog and digital do not co-exist well on the same RF carrier.

Makes you wonder why they won't allow wide band AM stereo broadcasts that would put out splatter but actually sound good and not mess up older receivers.

Precisely why I posed the possibility. The FCC wants to get rid of AM. Start with the smaller stations and work up.

Jeff in Sa-ra-so-ta!

 

[N1WVQ]

But what would the point be to get rid of A.M.? Is the A.M. band a headache to the F.C.C.? Plus, what else could be done with this slice of spectrum? It's practically an electromagnetic ghetto. Please note, I'm not asking these questions sarcastically or with malice. I'm genuinely interested in the thought of refarming the A.M. band to some other service. Not that I want it to happen but I'm curious as to what the thinking is. Unless the marine & aero beacons want more spectrum I don't see what other services could utilize it. This portion of spectrum certainly doesn't play nice with wideband digital (ahem).

 

[KeithE4]

But what would the point be to get rid of A.M.? Is the A.M. band a headache to the F.C.C.? Plus, what else could be done with this slice of spectrum? It's practically an electromagnetic ghetto. Please note, I'm not asking these questions sarcastically or with malice. I'm genuinely interested in the thought of refarming the A.M. band to some other service. Not that I want it to happen but I'm curious as to what the thinking is. Unless the marine & aero beacons want more spectrum I don't see what other services could utilize it. This portion of spectrum certainly doesn't play nice with wideband digital (ahem).

It would take an act of the ITU, as well as the FCC, to assign the AM band to another service. This is a worldwide allocation, at least up to 1600 kHz. Don't hold your breath waiting for it to go to somebody else. The herd could be thinned in the coming years to maybe 1000-1500 stations max, but it won't go away.

Besides, who would want it other than Amateur Radio (and we'll take every kilohertz we can get. ;D )?

 

[tomservo]

It wouldn't be a bad use of AM to continue it in the future as a strictly-analog regional service, eliminating much of the smaller stations in favor of those with high power, but that would necessitate moving those smaller stations to FM, or preferably in my mind, to VHF channels 5 & 6.

An expanded FM band (with optional IBOC, since the spacing could be adjusted from the get-go) and a super-regional AM band would be pretty neat.

 

[badjef]

It wouldn't be a bad use of AM to continue it in the future as a strictly-analog regional service, eliminating much of the smaller stations in favor of those with high power, but that would necessitate moving those smaller stations to FM, or preferably in my mind, to VHF channels 5 & 6.

An expanded FM band (with optional IBOC, since the spacing could be adjusted from the get-go) and a super-regional AM band would be pretty neat.

That won't happen. The receiver manufacturers won't see a point to leaving AM as an option in the radios. We have been seeing trends in that direction for years. There are rarely more than one level of presets for AM, while we have been seeing 2 or 3 levels of presets for FM.

Jeff in Sa-ra-so-ta!

 

[pianoplayer88key]

One thing I like about AM is that (to me it seems at least) there's the possibility of covering a greater area with a single transmitter. FM, except for tropo and e-skip, is mostly limited to a little beyond line of sight, whereas an AM station under the right conditions (for example good ground conductivity (especially saltwater), low dial position, efficient antenna (like a Franklin - KSTP's has an efficiency of 511.77 mV/m @ 1 km for 1 kW input power (KSTP is 50kW)), and a rural or less noisy area) can be heard several hundred miles away in the middle of the day on groundwave.

Speaking of noise on the AM band, I'd like to know how the FCC has fallen asleep at the switch with allowing various things to radiate so much on the AM band? Something I'm wondering about, and maybe those that are MUCH more experienced than I (for example were DXing in the 1950s or earlier) could answer this... Is it possible that the noise level is so much higher today, typically, that an AM station attempted on a high end communications receiver (Drake, Perseus, etc - name your choice) with a [/u]tuned[/u] (not broadband) beverage antenna would be totally undetectable today, whereas the SAME station at the SAME location, if you could time travel back to the 1930s with one of today's Coby ultralights (like the CX-70), would be as clear as FM HD (when it's working properly) with the ambient noise level so much lower?
And, is there ANY possible way things could be done to rein in the rampant QRN on the AM band and get the noise under control so signals can be RELIABLY heard at a distance?
Also how far, if you could take one of today's portables, like the Sony 2010, Tecsun PL-390, PL-606, Sony SRF-59, etc, back in time, might a typical 50kW clear have been heard in the daytime when there was no one else on its channel?

 

[Schroedingers Cat]

It wouldn't be a bad use of AM to continue it in the future as a strictly-analog regional service, eliminating much of the smaller stations in favor of those with high power, but that would necessitate moving those smaller stations to FM, or preferably in my mind, to VHF channels 5 & 6.

An expanded FM band (with optional IBOC, since the spacing could be adjusted from the get-go) and a super-regional AM band would be pretty neat.

That won't happen. The receiver manufacturers won't see a point to leaving AM as an option in the radios. We have been seeing trends in that direction for years. There are rarely more than one level of presets for AM, while we have been seeing 2 or 3 levels of presets for FM.

Jeff in Sa-ra-so-ta!

Ambient noise probably isn't more than that in the 1960s at least. If you can get away from the noisemakers, even in a car, you can still hear a 50 uV/m AM signal pretty well. Now remember that that 50 uV/m signal may show up on Radio Locator as a 150 uV/m signal.

There are so many issues to be resolved for an expanded FM band. AM Migration, Translators, and IBOC first adjacent channel interference reduction are a few possibilities for uses of an FM expanded band. Take Chicago for example. We see that WBBM is now going to be simulcast on FM, and that is one of the really good AM signals in a market of good AM signals. But what will WSCR, WGN, WLS, WMVP, WYLL, and WIND do for widespread FM coverage? There aren't enough full market FM signals to accommodate them all. And like Canada, there should be the opportunity for lesser AM signals to take over better AM station facilities that migrate permanently to an expanded FM band. For example, for WSCR, WBBM, WLS, and WMVP to just shut down their facilities upon migration wouldn't be a good use of spectrum.

 

[pianoplayer88key]

My preference for moving AMs to an expanded FM band (replacing TV 5 & 6, for example - 76 to 88 MHz) would be to mostly move the smaller AMs that have relatively small coverage footprints.

For example, if...
a particular AM (low power, high dial position, inefficient antenna, poor ground conductivity and/or crowded channel)...
cannot be detected by a DXer with a high-end ($1M+) 530-1700kHz-only (so as not to "waste" money on other bands) communications-grade receiver and beverage antenna, day or night (even factoring in once-in-a-hundred-years DX openings favoring the station - assuming EVERYONE else is off the air, there's a massive power grid total failure blanketing a 12,500-mile radius, your receiver is on battery power and the station's on generator), ...
but an FM at the same distance with the same power could be as clearly heard as a properly-working FM HD on a cheap pocket Coby radio (one with a built-in speaker) WITHOUT an antenna (read: headphones plugged into the headphone jack), ...
then I'd say move the AM to FM - among other things, the coverage should be improved, and it would clear up the AM frequency so it's not quite as crowded.
Before you think of moving ALL the low power AMs, though, I should mention that someone in Oklahoma recently heard a southern California station that's supposed to be only sending 12 watts his direction, and I've heard of TIS and Part 15 stations (when the frequency is clear) being heard thousands of miles away. (Well, maybe not thousands of miles for the part 15s, but hundreds.) That wouldn't, in my opinion, mean the station is "impossible" to hear. Sure, it might be rare, but there's still a chance. I've also heard the TIS's at DFW from southern California when the expanded AM band was first starting to be used.
Or should I not be trying to figure out how to accomodate the DXers that are looking to log sub-watt stations from thousands of miles away?


Also, S-Cat, you mentioned that in a "quiet" area a 50 µV/m signal could be heard fairly well. About what level signal would you say, under the best conditions (preferably groundwave to eliminate the variability of skywave), would be right at the noise floor, ranging from carrier barely detectable to program material barely discernible with good quality headphones? (I'm assuming a "fairly well" heard signal would be something like "arm chair copy" (able to listen at a moderate volume on a portable with a built-in speaker while washing dishes by hand across the kitchen, with the water in the sink masking the noise in the radio), or at least a good enough SNR as to be the type of signal that would trip the seek/scan on a typical consumer radio if it was receiving it that strong. A "clear" signal to me, at worst, has the RF noise floor far enough below the receiver's inherent noise floor so as to be undetectable.)

 

[JohnW]

Back to the original topic...

In Rochester, NY, it appears that God smote the IBOC on Crawford's WDCX (990) bible-thumper. Noticed it more than a week ago on a tune-by, and have periodically checked it since. IBOC still off. Also, CC's WHTK (1280) no longer has has the sideband hiss, even though their WHAM (1180) still does. Why they used IBOC on WHTK's all sports format was always a mystery to me.

 

[KeithE4]

Speaking of noise on the AM band, I'd like to know how the FCC has fallen asleep at the switch with allowing various things to radiate so much on the AM band? Something I'm wondering about, and maybe those that are MUCH more experienced than I (for example were DXing in the 1950s or earlier) could answer this...

Computing devices require square wave oscillators. Those, by definition, generate harmonics at odd multiples of their fundamental frequency. Analog TV horizontal-sweep circuits generate signals every 15.734 kHz, well up into the mid-MHz range. They've been around for 70 years and are finally starting to go away. If I put my AM radio near my big-screen LCD TV with a PC connected to it, and I hear very little noise - some, but not as much as my older equipment had.

Is it possible that the noise level is so much higher today, typically, that an AM station attempted on a high end communications receiver (Drake, Perseus, etc - name your choice) with a [/u]tuned[/u] (not broadband) beverage antenna would be totally undetectable today, whereas the SAME station at the SAME location, if you could time travel back to the 1930s with one of today's Coby ultralights (like the CX-70), would be as clear as FM HD (when it's working properly) with the ambient noise level so much lower?

In 1945, there were about 900 AM stations on the air, compared to around 4000 today. There were also very few TVs, and 90% of them were in the New York City area. You're comparing apples and oranges. Outside of a wholesale cleanup of the AM band (which is a subject for another board), we won't be going back to the way it was then.

And, is there ANY possible way things could be done to rein in the rampant QRN on the AM band and get the noise under control so signals can be RELIABLY heard at a distance?

Move to Antarctica, where there are no thunderstorms. ;D

 

[Savage]

Crawford's IBOC noisemaker on 990 kHz in Rochester has been off for a while, if memory serves (they don't make it down here to Avon particularly well, day or night, so I have to remember to try to listen to them when I'm in The Big Persimmon. And WHTK's 1280 sideband-hisser seems to come and go. It's never been used at night AFAIK.

Likewise, 990 kHz never has used IBOC at night.

 

[tomservo]

Makes me wish I were in Birmingham or Denver to sample other Crawford stations and see if this might the start of a much-needed trend.

As for WHTK doing HD sports on AM, I can top that: Birmingham's WJOX on FM runs mono analog but has recently turned the HD back on. Why is anyone's guess.

 

[DaveBayArea]

Makes me wish I were in Birmingham or Denver to sample other Crawford stations and see if this might the start of a much-needed trend.

FWIW - their 770 in Riverbank has it on during the day. I just checked and I can even decode it in the Bay Area - probably a distance of 50 miles from the xmtr. Given the programming and the non-proliferation of HD, I strongly suspect that I was the only HD listener while I was doing that test. But I have to give them kudos - not a lot of artifacts, so they're paying attention to the program source.

Can't hear them at night so I don't know whether they shut it off after dark or not.

Dave B.

 

[Chuck]

Makes me wish I were in Birmingham or Denver to sample other Crawford stations and see if this might the start of a much-needed trend.

I've been told that KAAM in Dallas has turned off the buzz. I don't know if it is true or not, but there is no mention of HD on their web site that I can find. It is a Crawford station.

 

[satech]

I've been told that KAAM in Dallas has turned off the buzz. I don't know if it is true or not, but there is no mention of HD on their web site that I can find. It is a Crawford station.

Hopefully they've turned back on the C-Quam, too. Crawford was a pretty big supporter of AM Stereo right up until they got bitten by the IBOC bug.

 

[muiscmike]

I've been told that KAAM in Dallas has turned off the buzz. I don't know if it is true or not, but there is no mention of HD on their web site that I can find. It is a Crawford station.

Hopefully they've turned back on the C-Quam, too. Crawford was a pretty big supporter of AM Stereo right up until they got bitten by the IBOC bug.

I just listened to a link that featured an AM stereo radio program and it sounded very good. Better than the HD-2 channels I've been listening to in my marker here in Ft. Myers, FL.

 

[badjef]

Crawford was a pretty big supporter of AM Stereo right up until they got bitten by the IBOC bug.

More like - stung - at this point.

Jeff in Sa-ra-so-ta!

 

[N1WVQ]

The Topaz list today is back down to 229. I think I've got 2 more stations off for him: WILD/1090-Boston & 1430/WKOX-Everett, Ma.. I couldn't hear hash on their carriers nor sidebands this morning. As I recall they've been off for some time.

73,
Jay, N1WVQ/V31VQ/WQBI410

 

[Savage]

More great developments in HD Radio: I see via another blogsite that Radio Shack has discontinued its last two HD products, both iOS adaptors which originally retailed for around $80. They're being closed out, no more available after current stock is cleared. Both sell for less than $20.

A year or two ago I would have started a new thread with this as the subject - but, what's the point any more? HD Radio is over. The AM version has been dead for about two years, with the only remaining operators committed to it being CBS and Greater Media, the sole reasons being face-saving and corporate-radio internal politics. HD-FM exists solely as a pretense for launching analog translators to introduce new signals and formats. Virtually nobody is listening to the "digital primaries."

HD receivers, long mired in the "hens' teeth" category, keep getting scarcer. What a really unfunny joke this whole thing has been. It's an embarassment to the radio profession that makes us look like nitwits to the rest of the media world.