‰  NOW 35 WPM  ‰  TEXT IS FROM JANUARY 2016 QST  PAGE 57‰

RTTY OPERATION AT THE TIME OF THIS REVIEW, AMERITRON HAD NOT SPECIFIED THE
100 DUTY CYCLE OUTPUT POWER NECESSARY FOR RTTY OR OTHER CONTINUOUS CARRIER
MODES.  ONE OPERATOR TRIED USING THE ALS 1306 DURING AN RTTY CONTEST, WHICH
TYPICALLY REQUIRES 5 TO 10 SECOND TRANSMISSIONS, FOLLOWED BY A SHORT
RECEIVING BREAK, OVER AND OVER AGAIN FOR AN EXTENDED PERIOD.  AT 1000 W
OUTPUT, HE NOTICED THAT AFTER A FEW MINUTES OF THIS, THE PA BALANCE METER
INDICATION CREPT HIGHER UNTIL THE PA WARNING LIGHT FLASHED.  REDUCING POWER
TO 600 700 W ALLOWED OPERATION TO CONTINUE.  WE REPORTED THIS EXPERIENCE TO
AMERITRON, AND THEY DECIDED TO TRY A DIFFERENT CORE MATERIAL FOR THE OUTPUT
TRANSFORMERS TO HELP WITH HEAT ISSUES.  THE NEW CORE MATERIAL IS USED IN
CURRENT PRODUCTION.  AS WE TRIED TO NAIL DOWN A RTTY POWER RATING,
AMERITRON INDICATED THAT SPECIFYING SUCH A RATING IS COMPLICATED AND
DEPENDS ON THE LOAD IMPEDANCE, SWR, AMBIENT AIR TEMPERATURE, DUTY CYCLE,
BAND OF OPERATION AND OTHER FACTORS SUCH AS COMPONENTS HEATING AND COOLING
AT DIFFERENT RATES.  BASED ON THE 350 W OUTPUT/10 MINUTE ON OFF/ 50 DUTY
CYCLE RTTY SPECIFICATION OF THE AMERITRON ALS 600 AMPLIFIER, I BELIEVE THAT
700 W FOR SAFE RTTY OPERATION IS ABOUT RIGHT, AS THE ALS 1306 IS
ESSENTIALLY TWO COMBINED ALS 600 AMPLIFIERS.  I TRANSMITTED 700 W FOR THE
60 SECONDS THAT MY DUMMY LOAD COULD TAKE THIS POWER LEVEL WITHOUT
‰  END OF 35 WPM TEXT  ‰  QST DE W1AW  ƒ