Voluntary AM all Digital?

I'm telling

I think the most telling part was saved for the last paragraph:

"“I think this is a uniquely positive step in AM revitalization,” Downs told Radio World on Tuesday. “We’ve talked for years about the rise in the noise on the AM band and how the quality of receivers has declined. But this is the first time we’ve had a chance to directly resolve both of these issues. With the approval of AM all-digital we have a technology that cleans up all the noise and hash we’ve been complaining about and sends an FM quality signal out of the speakers.”"

To me, that's Pai-in-the-sky thinking, simplistic at the very least, claiming that HD AM '..cleans up all the noise and hash we've been complaining about and sends an FM quality signal..' It makes it sound like it's a noise reduction system, or that a station is upgrading listeners to FM.

Commercial radio stations want positive answers, and are followers, so I think that statement is a shiny turd being thrown at them as a solution, because everything is better when it's digital, right? One time I was at a mall in my town, chatting with a friend. There was a guy standing next to me wearing headphones that said "Digital" on them, nothing else, just the word digital. Nothing digital about those phones, but some cheezy company had to write Digital on them to try to make them more appealing. That was ten years ago, and I still laugh about that.

I'd agree with you Station8, it's all Xperi (who license HD tech), transmitter, processor, and any AM HD gear manufacturer, they're the real drivers to this.

Do stations realize that if they switch they will disappear on the vast majority of radios, that the same noise heard on AM radios now will still interfere with HD, causing dropouts, or that the sound isn't really up to the levels of analog FM quality? Oops, I see that the article does say reception on analog radios will be lost for digital..

I've heard recordings of HD AM, including MA3, which is all digital mode, and I haven't heard anything close to FM, just better frequency response, but the delivery sounded like a Skype call. HD dropouts can be annoying, especially at higher volume levels, and the sound suddenly stops, it's disconcerting.

Radio stations, learn about your options, not just the sales pitch, as Station8 says, there hasn't been extensive testing.

Boomer

Nothing wrong with a good rant once in a while, especially on a topic that needs it.. It's not a tech article anyway, more of a quick announcement.

One good thing I can see coming out of it is if stations pay a lot of money to convert to HD, they might not abandon the band so quickly in the future, as long as we can keep interest and usage in AM.

Another thing is how new technology formats get better with time, as new ways are found to encode and decode it. It happened with FM, going on from phase modulators to direct FM on the transmission side, and receivers going from ratio detectors to PLL. AM receivers went from TRF to Superheterodyne. C-QUAM stereo AM even got better, at least to a third generation chip that dealt with issues in earlier chips.

Surely HD will improve its reception and audio quality if it sticks around. They have to get rid of that 'wha-wah pedal' sound to it first.

The all digital AM tests have been going on for a year in Frederick Maryland, and there hasn't been much discussion of the results. Where are the coverage maps, driving tests with videos showing reception, reviews on radios and sound qualities? I'd think they'd be crowing about the results all over the radio rags like Radio World, Inside Radio, and Radio Discussions board to try to be convincing. Actually I have to check that last one. I see many more stories from the woman pushing DRM in Europe all the time.

Right, it's just a code. I know about shorthand, my mom could write it.

Boomer

Admin said:
"One thing I always find curious is that for all the advances in radio being touted as "improvements", aircraft radio is still AM. NDB beacons are still AM. If digital and even FM are considered superior to AM, why are aeronautical radios still AM?"

This was explained to me once and can't exactly remember the technical reason(maybe timinbovey can explain) but FM or a digital transmission can't work with aviation communication.

Using Electronics

That's a cool book, like books I learned from too, junior science and electronics books, and the communications section of scouting books in the style of the day.

One book had a small AM transmitter like project 20 in your book, then a section on CB radio, and at the end of the chapter, it went into warnings about the FCC not being kind to scofflaws, and how they had cars equipped to capture illegal transmissions. An illustration showed an FCC sedan, with a loop antenna on the roof. I find that funny now, because after seeing that, what youngster would want to even build the radio projects in the book? That kind of talk is even scary to adults.

I'd like to see that book again, to see if it measures up to my memories of it. I don't remember the name, since I read a lot of science books like it.

The first project I can remember building was a neon bulb relaxation oscillator, with a bulb, diode, resistor and capacitor. I built it into a rubber replacement plug that had a larger barrel, so the components would fit inside of the plug, and the bulb stuck out of the hole for the cord. That might have been the one after I tested the circuit with an open version.

The figure 20 transmitter in your book is built like many of the early transistor FM transmitters from the 1960s-'70s, the base is at RF ground, and feedback is across collector and emitter through a capacitor. It's the same circuit, you'd just scale the coil and capacitors down for down for FM frequencies and use a high frequency transistor.

I see signs that kids still do radio projects, but probably not to the level of my one school where students were building crystal sets on wood bases. I wasn't in that class, but watched them at the door once, that was an upper grade.

One site laments something about AM radio, after the owner wanted to teach is young nephew how to build a radio, but he didn't continue, because of the quality of the programming being angry talk that you wouldn't want a kid to hear. That made me think how he should also have his student build the transmitter too!

Boomer

We used those to start our model airplanes. Called an ignitor, I looked for one to use as the "A" battery in my Radiola for the filaments.

I found them here:  BATTERIES IN A FLASH

But didn't want to spend that much.

I guess a 40 amp hour battery might be worth $25.