Transmitters, towers and antennas at NAB2001
Jun 1, 2001 12:00 PM, By John Battison, P.E., technical editor, RF
Discussions with FM engineers unearthed concerns about radio's future when considered with reference to streaming, DAB/IBOC, RBDS, satellite radio, and new applications of some laws of electronics such as the Crossed-Field Antenna and the EH Antenna.
Dielectric's 20MHz bandwidth FM antenna, designed for tower-top mounting, made its appearance this year.
A rather solid and unobtrusive device received a lot of attention this year from antenna manufacturers. Combiners, essential to hybrid IBOC operation, were displayed in all shapes and sizes, and varying claims of low insertion loss from companies such as Shively and ERI.
Andrew displayed a new coaxial cable, which uses an improved, corrugated center conductor that avoids center-conductor scoring caused by cable expansion and contraction.
Last year's NAB was full of anticipation regarding the CFA, and we had hopes for a high-power test in the Isle of Mann, but the tests have been delayed.
The AM transmitter field had an entry from Harris in the form of the 3DX50. This transmitter has a completely new design.
Nautel showed a solid-state 60kW AM IBOC transmitter with eight very efficient compact modules in the PA stage.
Broadcast Electronics' contribution this year was the 20kW solid-state transmitter, which includes a combiner and an innovative control system.
John Battison is the technical editor, RF, for BE Radio.