Rádio Nacional da Amazônia resumes DRM testing

Per Brother Rafael on DRMNA group: "tx is back!"

VOACAP plots for Rádio Nacional da Amazônia DRM Test

Brother Zyg has graciously provided us with VOACAP plots for the ongoing test. We are starting here with 20:00 UTC.Thanks Zyg! 

Rádio Nacional da Amazônia is on air with DRM on 11910 kHz

EBC & Brasília University running tests now on 11910 kHz DRM kHz from the transmitter site at Parque do Rodeador. Currently it is operating an average power of 1.12 kW into an HRS dipole curtain 4/4/0.5 at azimuth 320 degrees.

See previous post for further details. 

Details on Rádio Nacional da Amazônia DRM tests

With the recent excellent news coming out of Brazil, I took a few moments to contact our longtime DRM friend Rafael Diniz. He filled me in on some of the aspects of the upcoming DRM tests there:

Rafael, what is the current national status of DRM for digital broadcasting?

The digital radio discussion is stuck, mostly locked by the commercial broadcasters which publicity expressed against the digitization of the radio (citing, for example, the ongoing expenses of the broadcasters with the AM to FM migration, the crisis, and so on). Digital Radio seems a treat to the commercial broadcasting sector, but I will not elaborate more about it, as this discussion would take at least a 15 pages introduction.

 Can you tell us a little about the broadcast chain for this upcoming test? 

The broadcast chain will be a Brazilian BT Broadcast Transmitter 2.5kW HF tx, The exciter is a Digidia one, and the CS we'll experiment with different configurations, including Digidia and Fraunhofer options. The antenna is a huge HRS one beamed (with reflectors) to the north (good for US!), with between 16 and 20db of gain (Rodeador Park has many huge HRS antennas).

Will there be experiments similar to the recent work at KTWR using different parameters to see what works best? What about xHE-AAC?

We plan to use the best possible audio, which, if equipment permits, will be xHE-AAC audio and multimedia content. The idea is to also test 20kHz bandwidth, which will allow more than one audio program over the transmission, together with multimedia content.

 What will the content be?

Rádio Nacional da Amazônia content, the same of broadcast in 6,180 kHz and 11,780 kHz.

Is there any long term plan, or is this simply a feasibility test?

EBC is the process of purchase of two 100 kW DRM transmitters, to be delivered sometime in 2021 to really provide a steady digital reception even with the smallest battery powered receiver in all parts of the Amazon rainforest region. Concerning the long term - is the hope that this DRM transmission raise awareness of digital radio in the country and can change the minds of the commercial broadcasters about digital radio... and also save the MW band, which is getting empty - which is good and bad at the same time... with clear channels DRM nighttime reception can be fun again.

Thank you Rafael for your time and such great news. We look forward to more details and even more to signals making it to North America! Rádio Nacional da Amazônia is often heard here with great signal level and quality.

More news on Brazil DRM test

From our colleague in Brazil on 20150702:

Hi people,

Next week Ataliba (a friend of DRM-Brasil) will go to Brasilia with his HF rig (IC-725 modified to DRM signal input which goes directly to the PA.). The idea is to use his rig to be the first amplifier stage, as the past pre-amplifier we used was unacceptable with regards to MER, according to the Ministry of Communications engineer.

Ataliba is carrying for some time very successful DRM transmissions in ham radio 40m band. Sometimes with stereo audio content with 4W tx being decoded hundreds of kilometers away.

The idea is, if we get a good quality signal with ~150W on air, the official Brazilian SW digital radio trial will be able to begin,  There is no need for very high power tx for the measurements take place.

The trial will happen on Tuesday.

Cheers,
Rafael Diniz

Brazil test report from the DRM consortium

The original release is here:

"On May 28th Brazil experienced  the first DRM broadcast in short wave originating in Brazil mainly for Brazil.

The public broadcaster in Brazil, EBC, with the collaboration of partners broadcast in DRM in the afternoon of the 28th with 130W in DRM in the frequency of 9755kHz. The coverage area is predicted to encompass North – Amazonia as well as the south of the country, the richest part of Brazil and other neighbouring countries.

Despite the low power used the DRM signal has been already received successfully in parts of the country, being audible in quality in the Sao Paolo State at about 800km away from the transmission site in Brasilia. The audio of the Amazon National Radio was received there in excellent digital quality.

The transmission system was put together with Brazilian know how and with the assistance of EBC and key members of the DRM Brazilian Platform like Rafael Diniz, researcher at the Catholic University of Rio de Janeiro. Staff of the EBC and the Ministry of Communications chose to broadcast using one antenna system at Rodeador Park (EBC’s High Power SW Broadcast Centre). The antenna used has 16dB gain and north-south radiation pattern.

Tests are continuing and more measurements and feedback are to come in the next days and months."

Great news from Brazil

Update 20150602:

"Today arrived other amplifier made by a DRM-Brasil member, all without involving money (this is why things walk so slow). So EBC people will carry some tests with it, and after that transmission should restart, with a signal with better MER.
As the setup has little power, the crew involved is trying optimize the quality of the signal. So no signal today, and nothing happened yesterday also..."

This is not only good but triumphant news! Thanks to Brother Rafael.
---
"Tests will resume on Monday (1st June).
We'll inform the frequency soon.

Btw, on Thursday happened the first DRM SW transmission in Brazil! With 130W signal at 9755kHz was received by Claudio 780 km far away.

Big thanks to Michael Feilen, all guys at EBC and Ministry of Communications
involved in the trial.

Next week we'll be able to get another final stage amplifier in order to check if
we can get more power out."

Amazonia test reception

From Claudio PY2GVY: 780 km, from Brasilia, (GH64ah) to Limeira, SP (GG67hk), 100W, 9.755 KHz.

Radio Nacional da Amazonia works toward DRM

Our man on the scene, Rafael Diniz reports about work ongoing at Radio Nacional da Amazonia.

"Hi there people,

Past week I visited the Rodeador transmitter site of RNdA. 

I'm helping EBC engineers to put a DRM signal on ar. 

We are trying to connect the USRP / Spark to excite the the Continental Lensa tx, but it's giving us too much headache, I think the better will be to use the 250kW BBC tube tx instead at 6180kHz (currently off-air).

There are some pictures of the txs and antennas (and me!) here:
http://www.telemidia.puc-rio.br/~rafaeldiniz/public_files/ebc_drm_trial/

Best regards,
Rafael Diniz" 

Here is the satellite view of the antenna field. Thanks Rafael for the update. Be sure to tell us more as soon as you have the details! (via DRMNA Yahoo Group)