Featured Research

from universities, journals, and other organizations

New opportunity for AM radio

Date:
July 15, 2011
Source:
Elhuyar Fundazioa
Summary:
Radio broadcasters compete for airwave space in the saturated FM range, in detriment to AM wavebands with a poorer sound quality. Nevertheless, frequencies at wavebands less than 30 MHz (AM ones) could well have a new opportunity, with terrestrial digital radio broadcasting.

Experimental trials carried out in Brazil.
Credit: Image courtesy of Elhuyar Fundazioa

Radio broadcasters compete for airwave space in the saturated FM range, in detriment to AM wavebands with a poorer sound quality. Nevertheless, frequencies at wavebands less than 30 MHz (AM ones) could well have a new opportunity, with terrestrial digital radio broadcasting. The Digital Radio Mondiale (DRM) international consortium is working on the development of a universal system that will provide clarity which is close to that of FM, besides other advantages such as the multilingual option in programmes or a reduction of 40-50 % in electrical consumption.

Engineer Iván Peña, who works with DRM through the Signal Processing and Radiocommunication Groupat the University of the Basque Country (UPV/EHU), focused concretely on the study of the 26 MHz waveband. His thesis is entitled, Planning factors for digital local broadcasting in the 26 MHz band.

Mr Peña's research involved studying broadcasting models of propagation and planning factors in order to implement DRM services in the 26 MHz waveband. To this end, he carried out trials at a local level in countries such as Mexico, Brazil and Germany. Concretely, those of Mexico and Brazil were the first undertaken with this system. Besides, MHz is a waveband that has rarely been possible to use until now, and so its optimisation will have great repercussion. This is why Mr Peña's (jointly with the team he belongs to) research has been received at international congresses, as well as by the IEEE Transactions on Broadcasting journal, occupying, as it does, seventh position in the JCR classification for telecommunications.

To date only by ionospheric wave

As explained in the thesis, the only mode used to date for long-range radio broadcasting on the 26 MHz waveband was propagation through ionospheric wave. Here, the wave is refracted progressively, until regressing to the terrestrial surface from the ionosphere. Nevertheless, due to the fact that this method is affected by solar activity and frequency, it is not always possible to use it.

With the goal of using 26 MHz frequencies in a more efficient way, other modes of broadcasting that could facilitate the implementation of DRM services on this waveband have been experimented with in a local manner, this specific use having been started to be tested over the past decade. In fact, two techniques are being applied: one involves propagation by direct vision (the wave is made up of a direct ray, a reflected ray and rays refracted by the irregularities of Earth's surface), and the other, diffusion by surface wave (the wave is propagated by the earth-air discontinuity, adapting itself to the curvature of Earth). As explained by Mr Peña, despite the trials, there is a lack of knowledge about the system when applied to this waveband. His thesis contributes to characterising this type of radio broadcasting at a theoretical level, through the interpretation of the data obtained experimentally.

To begin with, Mr Peña undertook an analysis of propagation by terrestrial wave (in direct vision and surface wave modes) in this waveband, and drew up a prediction model that could identify local coverage of DRM networks found at each portion of the spectrum, in each situation. Moreover, he studied the conditions of ionospheric propagation which, at these frequencies, could cause interference amongst local digital radio broadcasting services. Finally, another contribution by this engineer was to determine the current levels of noise and to characterise other electromagnetic perturbations that might influence the quality and reliability of reception with these kinds of signals.


Story Source:

The above story is based on materials provided by Elhuyar Fundazioa. Note: Materials may be edited for content and length.


Cite This Page:

Elhuyar Fundazioa. "New opportunity for AM radio." ScienceDaily. ScienceDaily, 15 July 2011. <www.sciencedaily.com/releases/2011/07/110714072905.htm>.
Elhuyar Fundazioa. (2011, July 15). New opportunity for AM radio. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2011/07/110714072905.htm
Elhuyar Fundazioa. "New opportunity for AM radio." ScienceDaily. www.sciencedaily.com/releases/2011/07/110714072905.htm (accessed July 25, 2014).

Share This




More Matter & Energy News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) — TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) Video provided by AP
Powered by NewsLook.com
Creative Makeovers for Ugly Cellphone Towers

Creative Makeovers for Ugly Cellphone Towers

AP (July 24, 2014) — Mobile phone companies and communities across the country are going to new lengths to disguise those unsightly cellphone towers. From a church bell tower to a flagpole, even a pencil, some towers are trying to make a point. (July 24) Video provided by AP
Powered by NewsLook.com
Algonquin Power Goes Activist on Its Target Gas Natural

Algonquin Power Goes Activist on Its Target Gas Natural

TheStreet (July 23, 2014) — When The Deal's Amanda Levin exclusively reported that Gas Natural had been talking to potential suitors, the Ohio company responded with a flat denial, claiming its board had not talked to anyone about a possible sale. Lo and behold, Canadian utility Algonquin Power and Utilities not only had approached the company, but it did it three times. Its last offer was for $13 per share as Gas Natural's was trading at a 60-day moving average of about $12.50 per share. Now Algonquin, which has a 4.9% stake in Gas Natural, has taken its case to shareholders, calling on them to back its proposals or, possibly, a change in the target's board. Video provided by TheStreet
Powered by NewsLook.com
Robot Parking Valet Creates Stress-Free Travel

Robot Parking Valet Creates Stress-Free Travel

AP (July 23, 2014) — 'Ray' the robotic parking valet at Dusseldorf Airport in Germany lets travelers to avoid the hassle of finding a parking spot before heading to the check-in desk. (July 23) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

    Health News

      Environment News

        Technology News



          Save/Print:
          Share:  

          Free Subscriptions


          Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

          Get Social & Mobile


          Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

          Have Feedback?


          Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
          Mobile iPhone Android Web
          Follow Facebook Twitter Google+
          Subscribe RSS Feeds Email Newsletters
          Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins