SMALL STATION EMEON 70 AND 23 CM USING JT44/65

BY AL, K2UYH

OBJECTIVESOBJECTIVES

tGET YOU INTERESTED IN WORKING EME. (Most hams still believe exotic equipment, huge antennas, and very high power are needed to work EME.)tSHOW THAT YOU CAN ENJOY THE THRILL OF MOONBOUNCE WITH A MODEST SETUP. (Basically the equipment you already have.)t INCREASE EME ON 432 AND 1296 MHz.

(There is already a lot of small station EME on 6 & 2 m.)

WHY WORK MOONBOUNCEWHY WORK MOONBOUNCE

t IT IS EXCITING! tMOST FUN IN HAM

RADIO IS MAKING RARE, UNUSUAL, OR DIFFICULT CONTACTS.t EME ALLOWS YOU TO

WORK WORLDWIDE DX ON ANY BAND - 6 M UP. tWAY TO INCREASE

YOUR GRID SQUARE AND STATE COUNT.

K2UYHK2UYH

70 & 23CM 70 & 23CM

EMEEME

A BIG STATION IS NOT NEEDED!A BIG STATION IS NOT NEEDED!

tMY 1ST JT44 CONTACT WAS ON 23 CM WITH OH3MCK.tOH3MCK WAS USING 2 X 22 dBi YAGIES

(LINEAR POL.) AND 40 W.

OH3MCK

2ND JT44 QSO WITH OH1FF/p2ND JT44 QSO WITH OH1FF/p

t OH FIELD DAY STATIONt ALSO ON 23 CMt USING A 1.8 M DISH (CIR. POL?) AND 50 Wt WE COULD HAVE QSO’D VIA CW, BUT

JT44 DEFINITELY HELPED!

1ST JT44 ON 70 CM WITH ES8X1ST JT44 ON 70 CM WITH ES8X

tEUR. VHF FIELD DAY STATION ON KIHNU ISLAND (KO18xc). t4 x 12 EL YAGIS (WITH ELEV.) AND 300 W PA.

144 MHz

432 MHz

KIHNU IS A SMALL ISLAND ABOUT 40 KM OFF THE COAST OF ESTONIA IN THE GULF OF RIGA, BETWEEN ESTONIA AND LATVIA. (IN ESTONIA)

1ST JT44 ON 70 CM WITH ES8X1ST JT44 ON 70 CM WITH ES8X

tEUR. VHF FIELD DAY STATION ON KIHNU ISLAND (KO18xc). t4 x 12 EL YAGIS (WITH ELEV.) AND 300 W PA.

144 MHz

432 MHz

K2TXB OPERATES JT44 ON 2 mK2TXB OPERATES JT44 ON 2 m

tRUSS USES 2 X KLM 16 LBX YAGIS ON A POLAR MOUNT AND A KW.tWORKED 42 STATIONS IN 15 COUNTRIES AND 15 STATES

EME PRACTICEEME PRACTICEtEME OPERATED USING CONVENTIONAL (CW & SSB) OR

DIGITAL MODEStSOME STATIONS ARE EXPERIMENTING WITH DIGITAL

MODES AS PUA43 THAT PROVIDE MANY DB ADANTAGE, BUT REQUIRES SPECIAL EQUIPMENT AND TRADES TIME AND PRECISE FREQUENCY FOR SIGNAL LEVEL.tMOST DIGITAL EME IS WITH JT44/65.tJT44/65 USES STANDARD EQUIPMENT, WORKS IN

VIRTUALLY REAL TIME AND HAS RELAXED FREQUENCY STANDARDS.

JT44/65 BASICS -TXJT44/65 BASICS -TXtEACH TRANSMISSION IS 30/60 SECONDS LONG AND CONSISTS OF MESSAGE AND SYNC INFORMATION. (*JT65 CAN DECODE BF TX).tTHE MESSAGE IS 22/13* CHARACTERS LONG AND REPEATED 3 TIMES IN JT44.tTHE SYNC IS INTERSPERSED WITH THE MESSAGE AND SENT ABOUT HALF THE TIME.tA UNIQUE FREQUENCY IS ASSIGNED TO LETTERS, NUMERALS AND PUNCTUATION CHARACTERS (43 TONES) + SYNC = 44!tJT65 USES ERROR CORRECTING CODE --6 BITS/SYMBOLE (64 TONES) + SYNC =65!

JT44/65 BASICS - RXJT44/65 BASICS - RXAT THE END OF THE RECEPTION PERIOD JT44/65:• SEARCHES FOR TIME SYNC (SYNC PATTERN) OVER -4 TO 2 SECOND DELAY PERIOD.

• SEARCHES FOR FREQ OFFSET (+/- 600 Hz). • DETERMINES AND DISPLAYS MESSAGE.• JT44 - AVERAGES CHARACTERS IN EACH TIME SLOT OF THE 22 CHARACTER MESSAGE.

• JT65 – USES REED SOLOMON ERROR CORRECTION – NO GIBBERISH!

• JT65 HAS SPECIAL CODES FOR “O”, “OR”, “73”

VE7BBG’S JT44 SIGNALCOR RUNS A 7.5’ DISH AND 120W AT THE FEED

VE7BBG’S JT44 SIGNALCOR RUNS A 7.5’ DISH AND 120W AT THE FEED

TIME SYNC –

FREQ –-

TIME AMP -

AVERAGING IN JT44AVERAGING IN JT44tWHEN A SIGNAL IS STRONG CAN GET FULL COPY IN A SINGLE SEQUENCE –(QSO in < 2.5 min!)tOFTEN SIGNALS ARE WEAK AND THE MESSAGE GARBLED – (This is where JT44’s averaging pays off.)t IF THE SAME MESSAGE IS SENT EACH SEQUENCE, JT44 WILL AVERAGE THE RESULTS OF ALL PERIODS.tTHE MESSAGE WILL CORRECT ITSELF WITH EACH SUCCESSIVE PERIOD.

AVERAGING MADE THIS QSO POSSIBLE!AVERAGING MADE THIS QSO POSSIBLE!

JT65 VS. JT44JT65 VS. JT44tJT65 HAS 3 MODES: A, B AND C. JT44

TONE SPACING (Hz) 2.7 5.4 10.8 5.42.7 5.4 10.8 5.4dB ADVANTAGE 4.0 3.0 2.0 4.0 3.0 2.0 ------

tSPECIAL CODES HAVE EVEN GREATER ADVANTAGE.tSPECTRAL SPREADING AT HIGHER BANDS

DEGRADES JT65’S PERFORMANCE (if W > 5 use C).

OK1DFC’S JT65C SIGNALZDENEK RUNS A SINGLE YAGI ON HORIZ WITH 1 kW

OK1DFC’S JT65C SIGNALZDENEK RUNS A SINGLE YAGI ON HORIZ WITH 1 kW

TIME SYNC

FREQ –-

TIME AMP -

HE’S WORKED

2 YAGI STN

ECHO MODE – WANT TO TRY EVEN IF DON’T USE JT4465 FOR EME!ECHO MODE – WANT TO TRY EVEN IF DON’T USE JT4465 FOR EME!

tLET’S YOU EVALUATE EME SYSTEM CAPABILITY.tNOT GOOD FOR COMMUNICATIONS.tON 70 CM COPIED ECHOES WITH 200 W ON HORZ WITH

TROPO STATION.

STATION REQUIREMENTSSTATION REQUIREMENTS

IT DEPEND ON HOW BIG THE STATION IS ON THE OTHER SIDE?

tON 70 CM – SINGLE LONG YAGI AND > 100 W. *** WANT TO ELEVATE (REALLY A MUST)! *** PREAMP AT THE ANTENNA (AND PA AT ANT). *** POLARIZATION ROTATION?

tON 23 CM – SINGLE LONG LOOP YAGI OR 5’ DISH WITH CIRCULAR FEED AND > 50 W. *** CIRCULAR POL GAIN + 3 dB!

PORTABLE EME – DL3OCH STYLEPORTABLE EME – DL3OCH STYLE

tBODO USES IC-706, HB TRANSVERTER WITH 100 W AND A 59 EL YAGI (5 m long & 18.7 dBd) FROM HIS CAR.tBESIDES DL, HE HAS OPERATED FROM 3A, HB0, EA8...

ZB2/DL3OCH IN GIBRALTARZB2/DL3OCH IN GIBRALTAR

BODO CHOSE TO USE JT44 FORTHIS DXPEDITION..

YOU NEED A COMPUTER AND SOUND CARDYOU NEED A COMPUTER AND SOUND CARD

tSHOULD RUN 32 BIT VERSIONS OF THE WINDOWS OPERATING SYSTEM AND BE FAST ENOUGH TO HANDLE JT44/65 AND SEVERAL OTHER TASKS.

tA 300 MHz PENTIUM OR BETTER WITH WINDOWS 98 OR PREFERABLY WINDOWS 2000 OR XP WILL BE MORE THAN SUFFICIENT.

tNEED TO INTERFACE THE COMPUTER TO YOUR RIG: 1) PTT FROM SERIAL PORT (VOX will work), 2) TX AUDIO FROM AUDIO OUT OF SOUND CARD, & 3) RX AUDIO TO INPUT OF SOUND CARD.

(DL3OCH uses Acer laptop – 650 MHz Celeron)

OTHER SPECIAL REQUIREMENTSOTHER SPECIAL REQUIREMENTStFREQUENCY ACCURACY AND STABILITY

*** WANT TO BE WITH IN +/- 600 Hz. (No problem on 144 MHz, but on 1296 – Can tune?) *** FREQ DRIFT < FEW Hz IN 30 SECS. *** I USE GPS STANDARD.tDOPPLAR SHIFT CORRECTION

*** NOT IMPORTANT ON 144, BUT SIGNIFICANT ON 432 (can be > 1 kHz) AND 1296 (can be > 3 kHz). *** MUTUAL DOPPLAR CAN BE VERY DIFFERENT FROM LOCAL ECHO SHIFT! *** JT44 HAS BUILT IN CORRECTION.

(DL3OCH – nothing special)

OTHER REQUIREMENTS CONT’DOTHER REQUIREMENTS CONT’D

tMUST KNOW TIME TO ~ 1 SECOND. *** I USED RADIO SHACK WWV CLOCK AND SET MY COMPUTER BEFORE SKEDS *** SOFTWARE IS AVAILABLE TO AUTOMATICALLY TO UPDATE YOUR CLOCK VIA THE INTERNET <http://www.thinkman.com/dimension4/>. *** CAN ALSO USE GPS STANDARD.

tMUST BE ABLE TO TRACK THE MOON *** JT44 HAS BUILT IN TRACKING.

(DL3OCH has GPS & digital radio clock)

CONCLUSIONCONCLUSIONtEME WITH JT44/65 IS NEW AND CHALLENGING.t IT’S NOT JUST HAVING A YAGI, A100 W AND A COMPUTER!tTHE COMPUTER DOES NOT DO EVERYTHING FOR YOU!t IT IS PRETTY EASY WITH A BIG STATION, BUT THERE IS

STILL A LOT TO IT: ACCURATE FREQ AND TIME, MOON TRACKING, DOPPLAR, POLARIZATION (ON 432).tWITH A WEAK STATION, ALL THE ABOVE PLUS MUST

UNDERSTANDING HOW TO USE JT44/65 FULLY (EXCLUDE/INCLUDE, CLEAR, FOLD, FREEZE, CLIP, ETC.)tFOR SKEDS CHECK INTO K1RQG’S 20 M NET (14.345 MHz

1600Z SAT & SUN) AND READ 70 CM & UP EME NEWSLETTER <http://www.nitehawk.com/rasmit/em70cm.html> .

THANKS…….THANKS…….

tTO A LOT OF FOLKS,tESPECIALLY JOE, K1JTtAND RUSS, K2TXB – MY JT44 MENTOR,tAND TO ALL OF YOU FOR LISTENING.

QUESTIONS?