‰  NOW 40 WPM  ‰  TEXT IS FROM MARCH 2014 QST  PAGE 44‰

SUFFERS AT VERY LOW IMPEDANCES, AS WELL AS AT HIGH IMPEDANCES AT THE HIGHER
FREQUENCIES AS SUGGESTED BY TABLE 4.  POWER REQUIREMENTS THE MFJ 225 IS
POWERED BY FOUR AAA INTERNAL BATTERIES OR BY YOUR COMPUTERS USB PORT.
BECAUSE THE MFJ 225 PRIMARILY WILL BE USED AWAY FROM A COMPUTER, THE
INSTALLATION OF FOUR NIMH AAA BATTERIES IS RECOMMENDED.  YOU CAN USE
ALKALINE BATTERIES, BUT CHANGING THE BATTERIES IS NOT TRIVIAL.  YOU MUST
NOT ONLY OPEN UP THE CASE, BUT ALSO UNPL

LI ION BATTERIES HAVE MANY ATTRACTIVE FEATURES, SUCH AS HIGH CAPACITY, BUT
THEY ALSO EXHIBIT SOME SELF DISCHARGE AND MUST BE CHARGED IN A SPECIFIC
WAY.  SWAPPING BATTERY PACKS ISNT AS CONVENIENT AS FOR MANY OTHER RADIOS
BECAUSE THE CHARGING CIRCUIT IS IN THE RADIO, NOT THE CHARGER.  USING THE
RADIO THROUGH A LOCAL REPEATER AND FOR A FEW SIMPLEX CONTACTS ON THE
FLEXIBLE ANTENNA, THE MID LEVEL POWER SETTING ABOUT 2 W RF OUTPUT SEEMED
SUFFICIENT AND BATTERY LIFE WAS IN THE 3 TO 4 HOUR RANGE, WHICH IS QUITE
ACCEPTABLE.  OTHER USERS REPORTED UP TO 7 HOURS OF BATTERY LIFE WHILE
SCANNING.  THERE IS NO AA OR AAA PACK, BUT ONE SUPPLYING UP TO 10 V COULD
BE MADE UP TO ATTACH TO THE EXT DC PORT AND RECHARGE THE LI ION BATTERY.
AN AUTOMOTIVE ADAPTER IS AVAILABLE TO DROP THE VEHICLES 11 15 V SUPPLY INTO
THE RANGE ACCEPTED BY THE FT 252/257 5 TO 10 V.  NOTE THAT THE SUPPLIED AC
WALL CHARGER IS NOT INTENDED TO POWER THE RADIO WHEN THE BATTERY IS
DISCHARGED.  A SCARC MEMBER COMMENTED THAT THIS RADIO CANT BE ATTACHED TO
AN EXTERNAL 12 V 13R8 V SOURCE WITHOUT A SPECIAL ADAPTER, AND EXPLAINED, I
PREFER TO HOOK THE HANDHELD TO MY CAR DC SYSTEM AND CHARGE IT UP OR RUN IT

WHILE THE ARRL LAB MAKES GREAT MEASUREMENTS OF THESE AND OTHER RF
PARAMETERS, PROOF IS IN THE RADIOS PERFORMANCE IN THE FIELD.  I HAPPEN TO
LIVE NEAR A LARGE TOWER FESTOONED WITH ANTENNAS FOR A VARIETY OF HIGH POWER
VHF AND UHF TRANSMITTERS.  WHEN I DRIVE BY THIS LOCATION WITH A RECEIVER
THAT CANT CUT THE MUSTARD, THE RESULTING OVERLOAD CREATES BURSTS OF
SPURIOUS OUTPUT TONES AND SPEECH.  I TOOK THE HANDHELDS TO A PARKING LOT AT
THE BASE OF THE TOWER AND LET THEM SCAN THROUGH THEIR RECEIVE RANGES WHILE
CONNECTED TO AN EXTERNAL MOBILE WHIP.  THERE WERE A COUPLE OF SPURIOUS
RESPONSES HEARD, BUT OVERALL THE RECEIVERS STAYED PRETTY QUIET A GOOD
THING.  A SCARC MEMBER PRAISED THE RECEIVE AUDIO, SAYING, REPEATERS SOUNDED
VERY GOOD EVEN WHEN THEY WERE COMING IN WEAKLY.  ONE NOTE REGARDING
CONNECTING AN EXTERNAL OR AFTERMARKET ACCESSORY ANTENNA THE RADIOS SMA RF
CONNECTOR IS TYPICAL OF RECENT MODELS.  THE SMAS SMALL SIZE CAN MAKE IT
LESS THAN EASY TO SECURELY ATTACH A COAXIAL CABLE, WHICH REQUIRES A GOOD
FINGERTIP GRIP.  THE CONNECTOR WILL EVENTUALLY LOOSEN UP IF ITS NOT SNUG,
RESULTING IN INTERMITTENT OR NO CONTACT WITH THE SMA CENTER PIN.  THIS
ISSUE IS HARDLY UNIQUE TO THESE RADIOS, BUT IS WORTH NOTING GENERALLY.
BATTERY OPTIONS AND CHARGING THE FT 252/257 RADIOS USE A LITHIUM ION LI ION
BATTERY PACK SUPPLYING 7R4 V WITH A SPECIFIC ENERGY CAPACITY OF 1030 MAH.
‰  END OF 40 WPM TEXT  ‰  QST DE W1AW  ƒ