‰  NOW 35 WPM  ‰  TEXT IS FROM AUGUST 2012 QST  PAGE 47‰

PRODUCT REVIEW MFJ 994BRT AND MFJ 998RT REMOTE AUTOMATIC ANTENNA TUNERS
THESE HIGH POWER MATCHING NETWORKS MOUNT AT THE ANTENNA.  REVIEWED BY PHIL
SALAS, AD5X CONTRIBUTING EDITOR AD5X ARRL. NET  I PREVIOUSLY REVIEWED
SEVERAL REMOTE AUTOMATIC ANTENNA TUNERS SPECIFICALLY FOR USE WITH A 43 FOOT
VERTICAL ANTENNA.  THOSE REMOTE TUNERS WERE LIMITED TO ABOUT 200 W MAXIMUM
RF POWER, UNSUITABLE FOR STATIONS USING POWER AMPLIFIERS.  THIS HAS NOW
CHANGED WITH THE INTRODUCTION OF THE MFJ 994BRT 600 W AND MFJ 998RT 1500 W
REMOTE AUTO TUNERS.  A REMOTE ANTENNA TUNER MUST BE WEATHERPROOF AND
REMOTELY POWERED, AND IT MUST PROVIDE AUTOMATIC TUNING.  FOR A GIVEN RF
POWER HANDLING AND IMPEDANCE MATCHING SPECIFICATION, A REMOTE ANTENNA TUNER
WILL GENERALLY BE MORE EXPENSIVE THAN A DESKTOP UNIT BECAUSE OF THESE
REQUIREMENTS.  WITH MANY MANUAL AND AUTOMATIC DESKTOP MODELS AVAILABLE, WHY
USE A REMOTE ANTENNA TUNER?  ITS AN EFFICIENT WAY TO MATCH AN ANTENNA THAT
HAS A HIGH SWR AND IS FED THROUGH A RELATIVELY LONG LENGTH OF COAXIAL
CABLE.  SWR RELATED COAX CABLE LOSSES CAN BE HIGH WHEN THE ANTENNA SWR IS
HIGH EVEN IF AN IN SHACK TUNER PROVIDES A 1 1 SWR FOR YOUR EQUIPMENT.  YOU
CAN EASILY DEMONSTRATE THIS WITH ANTENNA MODELING SOFTWARE SIMULATIONS AND
A COAX/SWR CALCULATOR.  OVERVIEW THE MFJ 994BRT AND MFJ 998RT ARE REMOTE
VERSIONS OF THE CURRENT MFJ 994B 600 W AND MFJ 998 1500 W SWITCHED L
‰  END OF 35 WPM TEXT  ‰  QST DE W1AW  ƒ