Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: Prev 1 [2]   Go Down
  Print  
Author Topic: Elecraft.LW,MW BCB SW radio?  (Read 28528 times)
K5TED
Member

Posts: 820




Ignore
« Reply #15 on: May 26, 2013, 09:38:14 AM »

Actually, DRM is an open standard. Not everybody hates it. Some people do care about it.

Sure, the engineers who invented it and the lawyers who work for the companies that own the patents.  But what benefit will this bring to the average rural Indian person?  They probably already own an AM SW receiver, what is their incentive to purchase a new, expensive, and battery eating radio?  The noises that come out of the speaker will be the same, but at significantly greater expense and significantly greater power usage.

Good question. I don't know exactly what India aims to do with DRM, but they have invested heavily. So, it's not quite dead yet.

DRM is open source, open standard, so there's only the decoder licensing, should someone choose to use the Fraunhofer product. For PC users, it's either free or open, with Sodira or DReaM. The encoder software is also freely available.


I listen to RNZI DRM two or three times a week. I like it.

RNZI DRM broadcasts are there on schedule. Somebody cares.

As far as the sounds coming out of the speaker, the difference in sound and reception quality between analog and DRM are tremendous.
Logged
KE7TMA
Member

Posts: 472




Ignore
« Reply #16 on: May 28, 2013, 01:23:23 AM »

Actually, DRM is an open standard. Not everybody hates it. Some people do care about it.

Sure, the engineers who invented it and the lawyers who work for the companies that own the patents.  But what benefit will this bring to the average rural Indian person?  They probably already own an AM SW receiver, what is their incentive to purchase a new, expensive, and battery eating radio?  The noises that come out of the speaker will be the same, but at significantly greater expense and significantly greater power usage.

Good question. I don't know exactly what India aims to do with DRM, but they have invested heavily. So, it's not quite dead yet.

DRM is open source, open standard, so there's only the decoder licensing, should someone choose to use the Fraunhofer product. For PC users, it's either free or open, with Sodira or DReaM. The encoder software is also freely available.


I listen to RNZI DRM two or three times a week. I like it.

RNZI DRM broadcasts are there on schedule. Somebody cares.

As far as the sounds coming out of the speaker, the difference in sound and reception quality between analog and DRM are tremendous.


I do appreciate that the sound quality is better, if you have a strong enough signal to decode.  I guess my main point is that while I could see DRM being useful for a highly developed audience, the rural poor deep in the subcontinent probably can't afford either computers or DRM based radios.

I haven't listened to DRM, as my computer is too noisy to have in my shack.  I almost think its cheating in a way, though.  If I want I can just stream about anything I can receive on the SW bands but I enjoy spinning those dials!

I do remain a bit skeptical about digital broadcast and it's usefulness in areas with low signal strength.  We have a cabin in rural Minnesota and we went from getting 3 TV channels to none when the switchover happened.
Logged
K5TED
Member

Posts: 820




Ignore
« Reply #17 on: May 28, 2013, 08:23:59 AM »

By putting in several high powered transmitters, such as India has done, that signal strength problem should be eliminated. The interesting thing about analog vs DRM is that for a given signal strength of S7+, which is about the minimum required for lock and decode, many times the analog signal will still be noisy and uncomfortable to listen to, while the DRM signal will lock and provide clean sound.

Here's a quick cheap comparison. Excuse the use of Ustream over wireless and ensuing breaks and bad video, and the commercial, and the fiddling, but once I get going with the test and start switching between analog and DRM, the difference is quite notable.

 http://www.ustream.tv/recorded/33083621

Again, this is a really cruddy test, but there it is...

The analog signal is on 15mhz, the DRM on 17mhz. Both signals were S7+. Both bands noise floor was about the same. The problem with the analog signal was that it seems they use very little audio processing, so it struggles to stay above the noise. At the same time, the DRM signal was robust enough to carry the audio, and some side channel programming.
Logged
KE7TMA
Member

Posts: 472




Ignore
« Reply #18 on: May 28, 2013, 01:41:01 PM »

By putting in several high powered transmitters, such as India has done, that signal strength problem should be eliminated. The interesting thing about analog vs DRM is that for a given signal strength of S7+, which is about the minimum required for lock and decode, many times the analog signal will still be noisy and uncomfortable to listen to, while the DRM signal will lock and provide clean sound.

Here's a quick cheap comparison. Excuse the use of Ustream over wireless and ensuing breaks and bad video, and the commercial, and the fiddling, but once I get going with the test and start switching between analog and DRM, the difference is quite notable.

 http://www.ustream.tv/recorded/33083621

Again, this is a really cruddy test, but there it is...

The analog signal is on 15mhz, the DRM on 17mhz. Both signals were S7+. Both bands noise floor was about the same. The problem with the analog signal was that it seems they use very little audio processing, so it struggles to stay above the noise. At the same time, the DRM signal was robust enough to carry the audio, and some side channel programming.

What kind of SDR are you using?

I do realize that DRM has some definite advantages.  Most of the SWBC receivers out there, especially the lower cost models, do not have any form of noise reduction, blanking, variable filtering, and so forth, making them uncomfortable to listen to if the signal is marginal.  I guess my concern is that SWBC in India is used to serve the rural poor who may not even have reliable mains power, let alone a couple hundred for a new radio, or a computer that has the horsepower to decode DRM.

I do think that DRM has potential, and the mixed-mode data delivery is pretty neat, but it will take cheaper, smaller, and more efficient radios to really replace analog SWBC for the communities that it really serves.  We're just hobbyists, we can pop onto the internet and get our news that way, or stream the various programs if we wish.
Logged
K5TED
Member

Posts: 820




Ignore
« Reply #19 on: May 28, 2013, 06:03:33 PM »

The good thing is that nowadays, SDR receiver tech is very inexpensive. A low-cost netbook and USB dongle type receiver can do the job. Actually, that sort of kit has been around for a while. A few years ago, the Coding Technologies Traveler was the cheapest USB SDR with full HF, MW and VHF FM coverage, at $169. I used one as my travel radio, and ran it with a variety of laptops, including the old HP 1000 netbook with only a Atom proc.

Presently, there are many inexpensive USB receivers out there, from the Funcube to SoftRocks, etc. It's absolutely possible to cobble together a very workable SDR receiver, PC and all for around $150. Obviously that is a chunk of change for rural Indians, but the point is, the actual receiver itself is cheap, and can work on most any PC made in the last 6 or 7 years.

If you want to see some good examples of low cost implementations, join the DRMNA Yahoo group and take a look at the photo library.

There have been several attempts at marketing low-cost DRM portable radios, some with limited success and others that came and went, mostly as a function of bad marketing and poor planning. There's just too much competition in the US and EU from all the other electronic entertainment baubles to support any sort of meaningful market for DRM only radios in developed countries, but the ability to cover an entire region with digital audio and data in the form of cached webpages, using SW, MW or even VHF transmitter networks is attractive for a third world country.

 
Logged
K0JEG
Member

Posts: 679




Ignore
« Reply #20 on: May 28, 2013, 06:20:43 PM »

I do realize that DRM has some definite advantages.  Most of the SWBC receivers out there, especially the lower cost models, do not have any form of noise reduction, blanking, variable filtering, and so forth, making them uncomfortable to listen to if the signal is marginal.  I guess my concern is that SWBC in India is used to serve the rural poor who may not even have reliable mains power, let alone a couple hundred for a new radio, or a computer that has the horsepower to decode DRM.

I do think that DRM has potential, and the mixed-mode data delivery is pretty neat, but it will take cheaper, smaller, and more efficient radios to really replace analog SWBC for the communities that it really serves.  We're just hobbyists, we can pop onto the internet and get our news that way, or stream the various programs if we wish.

Same things were said of cell phones when moving from analog to digital. Turned out the digital phones were cheaper (by far). Remember a Raspberry Pi is all of $35 in the US, and the goal is to make them much less expensive in the developing world by using markup in North America and Europe to subsidize other countries. Any somewhat modern ARM processor has more than enough power to decode DRM or any other audio grade bitstream, and the RF portion is the same as any existing radios. A custom ASIC could be designed to handle the RF section as well, making a full DRM radio only a few chips.
Logged
K5TED
Member

Posts: 820




Ignore
« Reply #21 on: May 28, 2013, 08:34:41 PM »

We are at a place in SW broadcasting where the international broadcasters are looking for ways to put some lipstick on. VOA has been doing weekly tests with digital modes, sending text at up to hundreds of characters per second, digital and analog SSTV and MFSK images, plus html formatted pages over AM. It's actually quite amazing to see in action, while the announcer audio might be barely intelligible, the digital stream decodes flawlessly. It's called "VOARADIOGRAM". Quite interesting.
Logged
AD9DX
Member

Posts: 1519




Ignore
« Reply #22 on: June 30, 2013, 07:51:14 AM »

great idea. Take the KX3, omit the transmitter and mic jack, drop the price $200 and there you go.
Will Elecraft do this? No.

What did Transoceanics cost years ago? About $275 in 1964! That's much more than $799 adjusted for inflation.

It wouldn't just be a matter of removing the cost of the KX3 transmitter. It would be a matter of immensely broadening the universe of prospective buyers. The current pool of buyers for Elecraft radios is small, dwindling and old.

Much depends on the horizon of Elecraft management. If they want to leave the company to their kids, they'll have to go beyond ham equipment.


$275 in 1964 will cost you the princely sum of $2099 in 2012 dollars.
Logged

EX, KC9TRM, KB9IRZ
Pages: Prev 1 [2]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!