On page 4 of the Nov. 16 issue, Radio World featured the
thoughts of Mr. Ben Downs regarding the need for a significant change in the
delivery system of AM broadcasting (“Downs Advocates for AM Solutions”).
Mr. Downs can be of good cheer since there is a proven
alternative to amplitude modulation. This system is called Digital Radio Mondiale,
I am sure Radio World staff is fully aware of DRM, although
it is mentioned nowhere in Downs’ interview. For completeness I remind you
of the following qualifications of DRM as the replacement of amplitude
— DRM delivers FM broadcast-quality audio. It is
in use today by major European broadcasters (BBC, Radio Netherlands, Radio
France International, Voice of Germany, Voice of Russia) as an alternative to
amplitude modulation for long-wave, medium-wave and shortwave broadcasts.
Experimental testing is being conducted at VHF frequencies as an alternative to
the 200 kHz conventional FM signal.
— The DRM signal is 10 kHz in width, the same bandwidth
of a double-sideband AM signal. No significant change is needed to the
broadcast radio laws for its adoption since bandwidth and channel allocations
— DRM is an open-source digital system and has no
license fees associated with its use.
— U.S. company Continental Electronics has already
developed and is fielding DRM transmitters in other countries. Mr. Downs
should drive over to Dallas and see what is going on in his “backyard.”
— Asian and European countries are ready to adopt
DRM to replace their AM broadcast system. Most likely India and China will
adopt DRM and begin to manufacture receivers for DRM reception and decoding of
signals for their civilian markets.
DRM does not need new allocated frequencies or greater radio bandwidth
for its adoption. It can in almost every case simply be tuned
and connected to the existing station antenna on its existing frequency.
DRM is indeed a very merry message for the problems facing
Mr. Downs and all AM stations.
James V. Heck
The writer is retired
director of engineering of Radio HCJB-Quito, Ecuador, and World Radio