full digtial AM test proposed for IBOC

[audioguy]

I wouldn't care if they went all digital as long as it fits in the same exact bandwidth as an analog AM signal. Not the make-believe, emperor's new clothes "same bandwidth" of Ibiquity, which lives in a dream world of their own making. What is sad is that otherwise respected engineers have gone along with this fallacious idea. I won't name names but you know who I mean. For instance, the one that wrote an article about their new HD AM transmitter in a recent issue of Radio World.

I think the only AM stations that would be willing to go all digital would be those that are already a total failure, and thus have no audience to lose. Who else would be willing to switch off their entire audience except for two or three listeners that have HD AM radios?

At least if they confine their emissions to their own channel (unlike today), I would be able to listen to the OTHER stations on my dial in peace.

 

[KB1OKL]

The DRM station on 9.8 mHz was on loud, rude and whooshy last night, it's off so far today.

DRM is supposed to offer full quieting audio with no noise of any kind.
I strongly suspect your receiver was not in the DRM mode?

DRM spews hash 20 kHz wide on an analog receiver. I may have caught the last transmission last night as it has not been on today that I've noticed and believe me it's hard to miss during a band scan.

 

[rbrucecarter5]

I wouldn't care if they went all digital as long as it fits in the same exact bandwidth as an analog AM signal. Not the make-believe, emperor's new clothes "same bandwidth" of Ibiquity, which lives in a dream world of their own making. What is sad is that otherwise respected engineers have gone along with this fallacious idea. I won't name names but you know who I mean. For instance, the one that wrote an article about their new HD AM transmitter in a recent issue of Radio World.

I think the only AM stations that would be willing to go all digital would be those that are already a total failure, and thus have no audience to lose. Who else would be willing to switch off their entire audience except for two or three listeners that have HD AM radios?

At least if they confine their emissions to their own channel (unlike today), I would be able to listen to the OTHER stations on my dial in peace.

Listenability of the AM band is no longer a priority at the FCC.

 

[KeithE4]

Listenability of the AM band is no longer a priority at the FCC.

Maybe that's because so few people are listening.

 

[dumber than a box of hair]

Listenability of the AM band is no longer a priority at the FCC.

Maybe that's because so few people are listening.

Maybe so few people are listening because the FCC won't get off its high horse trying to decimate TV broadcasting in favor of broadband or worrying itself to death about 9/16 of a second of a bared breast and start enforcing its own rules.

 

[MarioMania]

Would Full Digital Only on AM work??

Would people start listen to AM again??

Think of KDKA/1020 and WBZ/1030 both being digital-only at 50,000 watts, with a 20 kHz channel width (1010-1030 and 1020-1040 kHz, respectively). Depending on receiving location and propagation, they'd clobber each other on 1020-1030. If the AM band were to go all-digital, the channel spacing would have to be 20 kHz instead of 10.

If that happens, KDKA has to move to 1010 and WBZ move to 1040 30 kHz apart..Would that work??

 

[dumber than a box of hair]

Would Full Digital Only on AM work??

Only if AM station owners have a death wish. All the signal propagation and interference issues that currently make AM-HD unusable unless you're right on top of the antenna site don't go away just because the analog signal goes away. The FCC resolutely refuses to enforce its own rules on interference from electrical and RF sources (Part 15, to be exact) and the band is severely overcrowded.

If that happens, KDKA has to move to 1010 and WBZ move to 1040 30 kHz apart..Would that work??

AM station allocations don't exist in a vacuum. Those moves you mentioned come at the expense of WINS and WHO, which would have to move elsewhere. A fundamental restructuring of the AM band, similar to what occurred in 1941, is not likely to happen in our lifetime, certainly not before the AM band is abandoned altogether.

 

[kenglish]

My sources at Radio Canada International say that there are still some other broadcasters using the Sackville facilities, for now.
No RCI any more, and Vatican was supposed to stop on Saturday.
I guess CRI (China) is the main tenant right now.

 

[fybush]

The remaining broadcasters from Sackville (through Oct. 31 unless they decide to stop sooner) are Voice of Vietnam, KBS (Korea) and NHK (Japan). CRI is apparently done already. CBC Northern Quebec is also still running from Sackville on 9625, but could stop at any moment once the CBC finishes building out four new FM relays up there.

 

[TimeIsTight]

When it comes to testing full digital on Medium Wave, there have to be markets where almost nobody listens to AM anymore, and where several stations have gone dark but the facilities haven't yet been torn down. In those situations there is little to lose with this kind of testing, especially if its done on lower power stations.

Ultimately, the FCC may want to allow full power digital in certain places and in certain parts of the band. Lower power stations on the high end in isolated markets might be a good place to start.

These tests are being proposed by iBiquity Digital Corporation, which, we all know, has its own proprietary system on which it would collect licensing fees on every transmitter and receiver.

One would hope that the FCC would also test the open source Digital Radio Mondiale system which is being adopted by countries in other parts of the world. In addition to being "fee free" when manufacturers gear up to make receivers, the economies of scale favor a world standard. From an economic perspective, "part" of the problem with HD radio in this country is the lack of receivers. If Digital Radio Mondiale becomes the new international standard many more radios will be manufactured and for sale that just come standard with digital reception, and that will become the new norm. That is much less likely to happen if the US stands alone with its own proprietary systems with licensing fees attached.

It is clear that AM is on its way to following vinyl records, dial telephones, typewriters and analogue televisions into the technology history books, on the other hand the spectrum is still usable and valuable if full digital is used.

While it may take decades before the big city 50-kw AMs on relatively clear channels lose all audience, in some markets the AMs have relatively few listeners now, and stations are going dark. It is possible that the FCC will let market forces clear the band before it attempts to start over with full digital, but it can't hurt to try it in places where those market forces have already taken the viability of AM broadcasting away.

The real game changer would be to get cell phone manufacturers to include medium wave digital reception, for emergency purposes, in all new cell phones. The case can be made that when the cell system goes down, radio is the only alternative, and medium wave offers advantages, as an emergency service, over FM. The case can also be made that cell phone manufacturers are a lot more likely to include the MW receiver circuits if the technology is open source, and doesn't carry proprietary fees with every cell phone made.

http://www.drm.org/

 

[mmnassour]

I don't want anything whatsoever in my 4G cell phone that sucks the battery even MORE than 4G does. The cell manufacturers will fight this one tooth and nail.

 

[K6JHU]

"The real game changer would be to get cell phone manufacturers to include medium wave digital reception, for emergency purposes, in all new cell phones. "

Go over to the Columbus board and see how well radio (with the apperant exception of one station) responded to an emergency.

 

[KeithE4]

The real game changer would be to get cell phone manufacturers to include medium wave digital reception, for emergency purposes, in all new cell phones. The case can be made that when the cell system goes down, radio is the only alternative, and medium wave offers advantages, as an emergency service, over FM. The case can also be made that cell phone manufacturers are a lot more likely to include the MW receiver circuits if the technology is open source, and doesn't carry proprietary fees with every cell phone made.

It is physically impossible to put a functional MW antenna inside a cellphone that's 1/4" thick. Besides, what "advantages" do stations on the AM band have over FM stations?

 

[TimeIsTight]

Besides, what "advantages" do stations on the AM band have over FM stations?

One major advantage the AM band offers is range, and reach. Here in the NYC area the 50-kw AMs are listenable at much longer distances than the FMs.

AM frequencies also offer the benefit of skywave in a "real" national emergency. The entire country could be covered with a relative handful of 50-kw stations on clear channels at night.

Some FM stations with their transmitters on tall city buildings don't have access to the required backup generators because flammable fuel isn't allowed inside the buildings.

On the other hand, the AM transmitters, out in the swamps, can have huge diesel backup generators and lots of room to store emergency fuel.

I don't want anything whatsoever in my 4G cell phone that sucks the battery even MORE than 4G does. The cell manufacturers will fight this one tooth and nail.

We're probably talking about circuits built into existing chips, with no meaningful increase in power consumption. These phones are really computers, and do very well handling all kinds of digital signals.

While unfortunately, most stations no longer assume a responsibility to offer emergency broadcast communications some are still well prepared. The regulatory planning would have to include incentives to make sure enough prepared stations could stay on the air.

 

[rbrucecarter5]

It is physically impossible to put a functional MW antenna inside a cellphone that's 1/4" thick. Besides, what "advantages" do stations on the AM band have over FM stations?

The Sony SRF-59 Walkman has a small ferrite bar and yet is noted for its sensitivity. Some AM chips now require only a single circular trace around the perimeter of the PC board to work.

We won't be seeing AM inside of cell phones any time soon, though. Too much interference from the cell phone circuitry itself. And it really is impossible to get an FM antenna into a cell phone. Walkmans utilize the headphone wire as an antenna. Cell phones rely on the handsfree wire. Sensitivity on FM without an adequate antenna would be really poor. Since HD is such a fragile reception scenario at best, HD reception would be even worse on a cell phone.

 

[TimeIsTight]

Let's not lose sight of the fact that all current cellphones are really digital radio receivers that also transmit. And the signals they adequately receive are far lower power and often lower signal strength than digital radio broadcast stations would provide.

The only difference would be the frequency of the new digital signals, VHF for FM, and Medium Wave for full power digital signals on current AM frequencies. While the longer wavelengths may provide some engineering challenges in adding proper electrically sized reception antennae for the digital VHF and MW signals, there are solutions in the research pipeline. It's a fixable problem, and the kind of challenge researchers love to solve.

Using an open source global system, and slightly modifying the chips that would go into hundreds of millions of future generation cell phones could bring the extra cost per phone down to pennies or less per unit. Once you design the extra chip circuit it doesn't cost you anymore to make the chips than it otherwise would, and possibly the different wavelength antennae would ad some negligible cost to phones that now cost tens to hundreds of dollars to make.

This is all very do-able, it's just that regulators have to see the need, and mandate that it happens. But the way things usually work is we have to encounter a nasty situation where this kind of extra communications backup would have made a super difference, and then it will be mandated at far greater cost. There were complaints that NYC's first responders two way radio systems didn't communicate with each other, police couldn't talk to fire, or ambulance etc, long before 911, but nothing was done until after the need was tragically demonstrated. Pennies per cell phone so it could get digital emergency radio if the power grid, or cell phone systems goes down would certainly be worth the added cost to all concerned. After all, most of us now carry cell phones most of the time. Is it better to have millions of Americans wandering around without a clue, or for pennies each to allow them to stay informed using digital radio, whether VHF or MW, when the cell network goes down? Like it did in the DC area a few days ago.

 

[rbrucecarter5]

After all, most of us now carry cell phones most of the time. Is it better to have millions of Americans wandering around without a clue, or for pennies each to allow them to stay informed using digital radio, whether VHF or MW, when the cell network goes down? Like it did in the DC area a few days ago.

Most cell phones already have FM capability - it just isn't turned on. If there needs to be an added chip, it will probably be analog radio, not digital. Sony and SiLabs have the best chips on the market, but it would almost have to be Silabs because it doesn't need inconvenient things like tuning capacitors and RF / IF coils, everything is inside. One chip, hookup up serial communication, audio, antenna - done. Whatever chip goes in there - it needs to be pennies. Anything HD has a huge license fee tacked on - so that millstone around its neck would doom its inclusion in radios. That is probably why the rumored iPhone FM function has never been enable. Apple wanted iTunes tagging, that takes HD, HD requires hefty fees and doesn't work worth a darn anyway, so Apple's business decision was to leave FM off and not pay the fee, fearing that iTunes purchases wouldn't pay for the HD fee in the long run. Smart move. Even smarter would be to enable it in analog mode only, and forego the iTunes tagging in favor of garnering good will with users who want a radio.

The sad fact is that radio listening is declining alarmingly - the smart phones have music players embedded, if you really want radio you can buy an SRF-59 for as low as $12. Or the digital display one for about twice that - SRF-83 I think. Best inexpensive receivers on the market, great for pulling in weak stations - something an cell phone radio wouldn't do anyway. It's a pain to carry a radio, and also carry a phone. But the sad fact is - radio gives what the corporate owners say people want, not what people want. So people revolted long ago for MP3 and iPod. They stream what they don't podcast on smart phones. So if the internet and cell towers go down, they are basically screwed for information.

All digital HD might be marginally better for reception, but I doubt it. Radio was, and still is inherently analog and so many reception scenarios exist that it is impossible to design a robust enough digital system. iBiquity tried and failed. All digital has some potential, but is it enough for AM in light of wi-fi, power lines, light dimmers, poorly designed consumer gear, etc. The ship has sailed for AM, the FCC could have regulated interference problems as they came up. But they did not and now it is too late to clean up the band from all the stuff attacking it.

 

[audioguy]

It would be very difficult to put an AM receiver with decent sensitivity inside a cell phone due to the long wavelength and high amount of self-noise generated by all of the other circuitry. You can't put a ferrite bar antenna inside a tiny cell phone with a metal case and expect it to work. The reason it works well in the Sony radios is that they have plastic cases and more room. E-field antennas aren't a good choice either; they pick up noise very easily, which is why they were mostly abandoned a long time ago.

The "advantages" of AM have largely been negated by ignoring the laws of physics and packing way too many stations into the band, causing a huge amount of co-channel interference. Add to that all of the noise from HD sidebands and the electrical noise of CFLs and just about everything with a clock inside, and AM is becoming unusable in a lot of situations. Digital transmission will NOT solve these problems. They are fundamentally due to the low frequency/long wavelength, lack of sufficient bandwidth, and electrical noise.

 

[Ai4i]

Great thread, and we all know of AM's who have reduced their facilities, are on again off again, turned their licenses in, or just can't find a stable format. Skywave reception is pretty much from a bygone era and the groundwave range of even the mightiest stations are not usually of sufficient quieting beyond the range of the major FM's in most any markets to handle digital sidebands. Admittedly, I have yet to sample a DRM receiver.

Expansion of the FM band down into television channels six and five has been floated about, but the only delivery system to come along in years which excites me remains this one. It reminds me of Eureka 147 in that a single bouquet is used, it is garanteed to have market-wide coverage equal to TV stations, is absolutely free from illegal operator interferrence, and as a free subscription service, should be free from mandated artistic disfigurement.

 

[jhardis]

The real game changer would be to get cell phone manufacturers to include medium wave digital reception, for emergency purposes, in all new cell phones. The case can be made that when the cell system goes down, radio is the only alternative, and medium wave offers advantages, as an emergency service, over FM.

This recurring idea that you should put a broadcast radio receiver in cell phones "for emergencies" is completely bogus. The newer cellular telephone standards already include a feature called "cell broadcast," in which an emergency message can be sent to all phones simultaneously, on a per-cell basis (that is, you send it only to the geographic area that matters). There's nothing technically that prevents the cellular carriers from broadcasting the same EAS/IPAWS messages that radio stations get to all cell phones, on the regular cellular frequencies. Furthermore, the phones can be programmed to do something smart with the EAS/IPAWS messages when received.

- Jonathan