The DRM decoders for computers are available on the web. However, the easiest way to decode DRM is to go to one of the hundreds of Kiwi SDR receivers that are on-line and click on DRM. Wideband shortwave radio receiver map
-
Get involved.
We want your input!
Apply for Membership and join the conversations about everything related to broadcasting.
After we receive your registration, a moderator will review it. After your registration is approved, you will be permitted to post.
If you use a disposable or false email address, your registration will be rejected.
After your membership is approved, please take a minute to tell us a little bit about yourself.
https://www.radiodiscussions.com/forums/introduce-yourself.1088/
Thanks in advance and have fun!
RadioDiscussions Administrators
US Domestic Shortwave
- Thread starter Radig
- Start date
There was chatter a few years ago that Brazil was going to revitalize domestic SW through the use of DRM, but that was when the economy was doing better. Seems those predictions became vaporcasts with the current economic downturn...and other technology has now passed by those plans. Same thing happened to Brazil's effort to expand FM down to 76 MHz...too late, no public interest.
Obviously you missed the DRM experiment in the last few months on 11910 kHz. Brazil Begins Shortwave DRM Broadcasts - RedTech
I heard the DRM datastream when it was on, as I posted earlier. I probably should have made clear that DRM seems to have become a non-starter amongst private broadcasters in Brazil. Perhaps it could be revived if the economy there improves but I have my doubts. Will be interesting to see if DRM really catches on in India, where it is being pushed hard.
And short wave is being phased out. Half the still-authorized SW stations are silent.
In India, there is very limited commercial broadcasting and mostly in the larger cities. The national and major regional services in many, many languages will all be converted to DRM and the process is now more than half finished. The government is subsidizing local production of receivers for lower income homes.
Private radio is FM only, but with about the same number of stations as there are in just California but for a nation of 1.3 billion. There are no private AM stations.
India is another country where SW is being phased out. Over the past two years over two dozen All India Radio domestic service SW transmitters have been decommissioned. And in just the past year most of the AIR international SW services have been eliminated.
Many, if not most of the SW transmitters were very old and at the end of their service life.
A good example of SW and its status is HCJB. At one time, they had a huge complex even with its own hydro plant in Ecuador. When the site was needed for the new airport, they evaluated SW and decided not to rebuild. Instead, they located some gear to SE Asia to broadcast into China, where there was, of course, no other way to reach people other than SW.
At one time, HCJB could broadcast 7 or 8 different regional, national and international services at the same time.
Back in the day I would occasionally listen to HCJB when they would read reception reports and various letters from listeners, some of which made the false assumption that their programming was prerecorded in the U.S. The program hosts would correct the listener and tell them "no we're live and direct from Quito". Apparently many Americans couldn't believe that anyone who lives outside the U.S. can't speak English without a heavy "foreign" accent.
K
kenglish
Guest
Was the reason behind HCJB going away because the new airport was to be built there, or because the existing HCJB was in the flight path of the new airport?
The airport proposal was in the making for many years.
I seem to remember something about leaving a single domestic service, but maybe a smaller tower or different location, when they moved out. I think it was a donation to the community.
The airport proposal was in the making for many years.
I seem to remember something about leaving a single domestic service, but maybe a smaller tower or different location, when they moved out. I think it was a donation to the community.
Agree. DRM has been around for over twenty years. Unless as with India, the local government is willing to buy receivers, I don't think its going to take off like wildfire, and certainly no savior to SW. It's WAY too late for the U.S. and Europe.
The river with their hydro plant had to be re-channeled and the site was partially to be used for the airport grounds and some towers were going to be too near flight paths. Remember, a SW station does not have particularly tall towers.
They started working on the airport plans back in the 60's. The Mariscal Sucre airport was daytime only.
The location was too far from the city for less than a 50 kw AM, so as far as I know, nothing was left. The "community" did not need a donated station as Quito, by that time, had 32 AM stations and over 40 FMs.
They even had an English language 1st to 12th grade school for the missionaries and a small hospital, too. That part was in the urban area of Quito, fairly near the old airport.
K
kenglish
Guest
I have a recording of what may be the last HCJB broadcast from Quito. I tried to verify that with their management in the US, and their Quito engineers, but it never was decided.
I was going to send it to a friend, who was a retired volunteer engineer of theirs.
I was going to send it to a friend, who was a retired volunteer engineer of theirs.
Indeed, unlike medium wave AM stations which generally use guywire or freestanding towers as the radiating elements, most high power SW stations use what are called "Curtain Antennas". The towers are only needed to support wires and the associated insulators.
And, compared to AM towers... particularly at the low end of the dial... they are not particularly tall.
I'm guessing that a significant percentage of the computers in Cuba are in government offices, military facilities, government hospitals (the only kind they have), factories, food processing plants, media and so on. I'd guess that less than a third are in the hands of private individuals.
K
kenglish
Guest
The support towers for KUSW's Log Periodic were 145 feet (pretty small for an AM, series-fed).
A curtain-array might be a lot taller, since the number of "dipoles" sets the vertical pattern.
A curtain-array might be a lot taller, since the number of "dipoles" sets the vertical pattern.
The support towers for the TCI low-band 6x4 (six rows high, four wide, 24 diploes) curtain array antennas (24 dipoles) at the VOA Morocco Transmitting Station were about 400 feet.
The TCI low-band support towers for the 4x4 antennas (16 dipoles) run about 300 feet or so.
The few examples of TCI literature for the 611 series antennas that I looked at did not discuss tower heights.
Last edited:
K
kenglish
Guest
That sounds about right. The KUSW log-periodic had a fixed takeoff angle. They never changed target areas.
I'd love to see some of those big curtains. There's a lot of pictures and info in the book, "Radio Antenna Engineering", edited by Edmund LaPorte, that showed those things being built in the 40's and 50's.
Wow!!
Radio Nacional de amazonais on 11780khz from Brazil just blasts into Alaska in the spring/summer late afternoons
- Status