Echos of HD - DRM to suppliment AM-HD ?

[PocketRadio]

"Shortwave Awaits DRM in United States"

"So far retailers like RadioShack have not yet shown much interest in selling DRM receivers. The numbers [they need] are very big, said Penneroux, with 2.5 billion receivers to renew worldwide... Some participants at the meeting said that there may also be a role for DRM in AM broadcasting in the United States, given the controversy over problems with IBOC at night. They speculated that combined DRM/HD Radio receivers might be on the horizon."

http://www.rwonline.com/pages/s.0049/t.7242.html

"DRM: Ready for Global Deployment"

"In the world of digital radio, it’s a long road from working system to market penetration, as developers of digital radio technologies have discovered to their frustration over the past two decades."

http://www.rwonline.com/pages/s.0049/t.7241.html

Here we go again - looks like RS has learned that consumers are not interested in replacing perfectly fine analog receivers with expensive versions. As with HD Radio, LOL !

 

[K6JHU]

But at least DRM can be decoded with a PC and a Sound Card. No expensive hardware requried.

 

[dbdigital]

One interesting proposal mentioned in the article was this:

"There is also a great deal of interest in the United States and other countries in using DRM on the 26 MHz band for low-powered local FM-quality broadcasting... the High Frequency Coordinating Conference, where most shortwave frequency planning is done worldwide, recently proposed a division of the band, with one portion to be used for international broadcasting and the other part for local DRM broadcasts."

It wasn't stated how much of the SW band would be allocated for local broadcasts but if it did come to pass it would, of course, break iBiquity's lock on digital radio for the U.S.

The article also indicated China's desire to impliment DRM for its local broadcasts and the possibility of the Chinese building dual-standard digital radios, HD and DRM. Given China's ability to flood any market with cheap products this also could allow, in a back door sort of way, the use of DRM on AM here as well.

At any rate, some interesting developments are in the works for DRM.

db

 

[K6JHU]

If I were an AM broadcaster with trying to get a jump on the future, I would apply for an SW license on 26MHz. My guess is that 100W and a diople antenna (about 30 feet long) would get you in the running well ahead of the pack. And at the moment 100W on 26 MHz might get you 20-30 miles of ground wave with no interfence. Kind of like FM in the 50's.

 

[Chuck]

If I were an AM broadcaster with trying to get a jump on the future, I would apply for an SW license on 26MHz. My guess is that 100W and a diople antenna (about 30 feet long) would get you in the running well ahead of the pack. And at the moment 100W on 26 MHz might get you 20-30 miles of ground wave with no interfence. Kind of like FM in the 50's.

That would be a tremendous opportunity that might put some "local" back in broadcasting. Existing graveyard AM's could get into 26 MHz very cheaply, assuming the DRM part doesn't eat them alive (which I doubt). The rest of the equipment and the electric bill wouldn't be a very big deal. There are some real disadvantages to 26 MHz, which pretty well explains why it is under used right now. Even so, if I could, I'd jump on it in a minute. I suspect a lot of other small broadcasters would too.

 

[Play Freebird]

If I were an AM broadcaster with trying to get a jump on the future, I would apply for an SW license on 26MHz. My guess is that 100W and a diople antenna (about 30 feet long) would get you in the running well ahead of the pack. And at the moment 100W on 26 MHz might get you 20-30 miles of ground wave with no interfence. Kind of like FM in the 50's.

Unfortunately, at this time, the FCC will not grant shortwave broadcast licenses unless at least 50 kW transmitter output and a high gain antenna are proposed. However, your hunch is correct; the 26 MHz band should provide surprisingly good coverage in most areas. I'm located near Philadelphia and consistently copy the KQ2H 10-meter FM repeater on 29.62, located way up in Wurtsboro, NY, even while mobile on our local roads. On trips to New Hampshire, I've followed it well north of Albany into Vermont. Google KQ2H for more info.

 

[dbdigital]

Just out of curiosity, would the atmospheric anomilies that plague international SW broadcasts at certain times of the year also affect local SW broadcasts? And if so, what would be a strategy for overcoming it? I know that SW stations will switch frequencies at different times of the year but I don't think that would be feasible for local broadcasts.

db

 

[K6JHU]

Short answer is yes. And not just SW. Atmospheric and elctromagnetic phenoma affect transmiisons up to 148 MHz and above. It is possible to talk to Hawaii on VHF when conditions are right.

One of the reasons that CB is at 27 MHz is that it is too high for reliable long distance communcations and not local enough for short distances ('Hello skipland'). Nobody wanted the band so it was assigned to CB

 

[KeithE4]

One of the reasons that CB is at 27 MHz is that it is too high for reliable long distance communcations and not local enough for short distances ('Hello skipland'). Nobody wanted the band so it was assigned to CB

Actually, it was a ham band from 1947 to 1958, shared with ISM devices (which still can use it today). It was supposed to compensate for frequency losses on 10 and 20 meters. Hams didn't use it much so it was removed in favor of CB.

 

[jegrant]

I'd really like to buy one radio that decodes DRM (on AM, SW, and LW), HD (AM & FM), and FM eXtra. And it should have a USB port for future upgrades, in case any new codecs or modulation schemes are introduced. (FWIW I'd even be willing to pay a one-time fee for such an upgrade, such as $5 or $10, if new codecs required licensing fees.)

 

[hipporadio]

My guess is that 100W and a diople antenna (about 30 feet long) would get you in the running...

That sounds darn-near like the typical transmit/receive scenario for IBOC on FM