‰  NOW 40 WPM  ‰  

AMPLIFIER RELAYS IN THE TRANSMIT DIRECTION, AND AMPLIFIER BIAS PROPERLY SET
FOR LINEAR OPERATION.  LEAVING THE AMPLIFIER KEYED CONSTANTLY MAY CAUSE A
HEAT PROBLEM, ESPECIALLY IN THOSE AMPLIFIERS THAT DO NOT EMPLOY DYNAMIC
BIAS CONTROL.  ENTER THE QSK 2500 BILL RODGERS, K3HZP, THE OWNER OF DX
CONNECTION, DEVELOPED THE QSK 2500 TO HANDLE AMPLIFIER SWITCHING FOR BOTH
QSK AND NON QSK OPERATION.  ALL SWITCHING IS ACCOMPLISHED WITH SEQUENCED
HIGH SPEED, HIGH RELIABILITY SEALED RELA

METERS.  THE DISPLAYED FREQUENCY OF 4R061 MHZ IS THE UPPER FREQUENCY LIMIT
OF THE SWEEP.  CONCLUSION THE CAA 500MARKII IS A REASONABLY PRICED
HF/VHF/UHF ANTENNA ANALYZER.  THE LARGE CROSS NEEDLE METER IS NICE WHEN
MAKING ANTENNA SYSTEM ADJUSTMENTS.  AND ALTHOUGH IT IS SMALL, THE COLOR LCD
PROVIDES ADDITIONAL SWR AND IMPEDANCE INFORMATION, AS WELL AS BAND SWEEPING
CAPABILITY.  A PADDED NYLON SOFT CASE WITH SHOULDER STRAP AND BELT LOOP IS
AVAILABLE TO PROTECT THE INSTRUMENT DURING FIELD USE.  YOU CAN INVESTIGATE
THE CAA 500MARKII FURTHER BY VIEWING THE MANUAL ON THE COMET WEBSITE.  DX
CONNECTION QSK 2500 HIGH POWER EXTERNAL QSK SWITCH REVIEWED BY PHIL SALAS,
AD5X AD5X ARRL. NET  A FEW YEARS AGO, AN ARRL WEBSITE POLL INDICATED THAT
APPROXIMATELY 30 OF AMATEURS HAVE AN AMPLIFIER.  ONE OFTEN OVERLOOKED ISSUE
IS TRANSCEIVER/AMPLIFIER TIMING, ESPECIALLY FOR THOSE WHO OPERATE CW.  THE
TYPICAL AMPLIFIER WITHOUT FULL BREAK IN QSK CAPABILITY USES A TRANSMIT
RECEIVE TR RELAY THAT TYPICALLY TAKES 12 20 MILLISECONDS TO SWITCH AND
SETTLE.  MOST TRANSCEIVERS HAVE A DEFAULT RF DELAY AFTER AMP KEY TIME THAT
IS LESS THAN THIS, ALTHOUGH MANY MODERN TRANSCEIVERS OFFER AN ADJUSTABLE

USING THE CAA 500MARKII THE CAA 500MARKII IS VERY EASY TO USE IN THE
DEFAULT SINGLE FREQUENCY MEASUREMENT MODE.  THE BAND SWITCH SELECTS THE
FREQUENCY RANGE OF INTEREST, AND THE FREQ CONTROL SETS THE MEASUREMENT
FREQUENCY WITHIN THIS RANGE.  SWR AND THE MAGNITUDE OF THE IMPEDANCE ARE
INDICATED ON THE CROSS NEEDLE METER, AND THE LCD PROVIDES ADDITIONAL
DIGITAL AND BAR GRAPH SWR AND IMPEDANCE INFORMATION.  BOTH THE AUTO AND
MANUAL SWEEP MODES DISPLAY SWR ONLY 6 1 MAXIMUM.  FOR THE AUTO SWEEP MODE,
THE BAND SWITCH AND FREQ CONTROL SELECT THE AMATEUR BAND OF INTEREST.  THEN
PRESSING SWEEP CENTER SWEEPS THE SELECTED FULL AMATEUR BAND.  FOR THE
MANUAL SWEEP MODE, PRESS GRAPH ON/OFF AND SET THE DESIRED CENTER FREQUENCY.
THEN PRESS THE SWEEP/ CENTER BUTTON, SET THE BAND SWEEP LIMITS, AND PRESS
A.P. OFF TO CONFIRM THE SETTINGS.  NOW MANUALLY SWEEP THE SWR OF THE
SELECTED BAND WITH THE FREQ CONTROL.  IN THE MANUAL SWEEP MODE, YOU CAN
CHANGE THE SWEEP COLORS AND OVERLAY UP TO FIVE MANUAL SWEEP RESULTS IN THE
DIFFERENT COLORS.  THIS PERMITS YOU TO SEE THE IMPACT OF CHANGES AS YOU
ADJUST YOUR ANTENNA SYSTEM.  MY PRIMARY ANTENNA IS A 43 FOOT VERTICAL WITH
A 160/80 METER BASE MATCHING NETWORK.  FIGURE 2 SHOWS THE 160 METER FIXED
FREQUENCY CROSS NEEDLE AND DIGITAL DISPLAY AT THE LOWEST SWR POINT.  FIGURE
3 SHOWS THE FULL BAND SWR SWEEP OF THE MATCHED 43 FOOT VERTICAL ON 80
‰  END OF 40 WPM TEXT  ‰  QST DE W1AW  ƒ