SMALL STATION EME ON 70 AND 23 CM USING JT44/65 BY AL, K2UYH.
SMALL STATION EME ON 70 AND 23 CM USING JT44/65
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SMALL STATION EME ON 70 AND 23 CM USING JT44/65 BY AL, K2UYH
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SMALL STATION EME ON 70 AND 23 CM USING JT44/65. BY AL, K2UYH. OBJECTIVES. GET YOU INTERESTED IN WORKING EME. (Most hams still believe exotic equipment, huge antennas, and very high power are needed to work EME.) - PowerPoint PPT Presentation
Transcript of SMALL STATION EME ON 70 AND 23 CM USING JT44/65
SMALL STATION EME ON 70 AND 23 CM USING
JT44/65
BY AL, K2UYH
OBJECTIVESOBJECTIVESGET YOU INTERESTED IN WORKING EME. (Most hams still believe exotic equipment, huge antennas, and very high power are needed to work EME.)
SHOW THAT YOU CAN ENJOY THE THRILL OF MOONBOUNCE WITH A MODEST SETUP. (Basically the equipment you already have.)
INCREASE EME ON 432 AND 1296 MHz. (There is already a lot of small station EME on 6 & 2 m.)
WHY WORK MOONBOUNCE
WHY WORK MOONBOUNCE
IT IS EXCITING! MOST FUN IN HAM
RADIO IS MAKING RARE, UNUSUAL, OR DIFFICULT CONTACTS.
EME ALLOWS YOU TO WORK WORLDWIDE DX ON ANY BAND - 6 M UP.
WAY TO INCREASE YOUR GRID SQUARE AND STATE COUNT.
K2UYH
70 & 23CM
EME
A BIG STATION IS NOT NEEDED!
A BIG STATION IS NOT NEEDED!
MY 1ST JT44 CONTACT WAS ON 23 CM WITH OH3MCK.
OH3MCK WAS USING 2 X 22 dBi YAGIES (LINEAR POL.) AND 40 W.
OH3MCK
2ND JT44 QSO WITH OH1FF/p2ND JT44 QSO WITH OH1FF/p
OH FIELD DAY STATION ALSO ON 23 CM USING A 1.8 M DISH (CIR. POL?) AND 50 W WE COULD HAVE QSO’D VIA CW, BUT
JT44 DEFINITELY HELPED!
1ST JT44 ON 70 CM WITH ES8X
1ST JT44 ON 70 CM WITH ES8X
EUR. VHF FIELD DAY STATION ON KIHNU ISLAND (KO18xc).
4 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 ES8X
1ST JT44 ON 70 CM WITH ES8X
EUR. VHF FIELD DAY STATION ON KIHNU ISLAND (KO18xc).
4 x 12 EL YAGIS (WITH ELEV.) AND 300 W PA.
144 MHz
432 MHz
K2TXB OPERATES JT44 ON 2 m
K2TXB OPERATES JT44 ON 2 m
RUSS USES 2 X KLM 16 LBX YAGIS ON A POLAR MOUNT AND A KW.
WORKED 42 STATIONS IN 15 COUNTRIES AND 15 STATES
EME PRACTICEEME PRACTICEEME OPERATED USING CONVENTIONAL (CW & SSB) OR
DIGITAL MODESSOME 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.
MOST DIGITAL EME IS WITH JT44/65.JT44/65 USES STANDARD EQUIPMENT, WORKS IN
VIRTUALLY REAL TIME AND HAS RELAXED FREQUENCY STANDARDS.
JT44/65 BASICS -TXJT44/65 BASICS -TXEACH TRANSMISSION IS 30/60 SECONDS LONG AND CONSISTS OF MESSAGE AND SYNC INFORMATION. (*JT65 CAN DECODE BF TX).
THE MESSAGE IS 22/13* CHARACTERS LONG AND REPEATED 3 TIMES IN JT44.
THE SYNC IS INTERSPERSED WITH THE MESSAGE AND SENT ABOUT HALF THE TIME.
A UNIQUE FREQUENCY IS ASSIGNED TO LETTERS, NUMERALS AND PUNCTUATION CHARACTERS (43 TONES) + SYNC = 44!
JT65 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 FEEDTIME SYNC –
FREQ –-
TIME AMP -
AVERAGING IN JT44AVERAGING IN JT44WHEN A SIGNAL IS STRONG CAN GET FULL COPY IN A SINGLE SEQUENCE – (QSO in < 2.5 min!)
OFTEN SIGNALS ARE WEAK AND THE MESSAGE GARBLED – (This is where JT44’s averaging pays off.)
IF THE SAME MESSAGE IS SENT EACH SEQUENCE, JT44 WILL AVERAGE THE RESULTS OF ALL PERIODS.
THE MESSAGE WILL CORRECT ITSELF WITH EACH SUCCESSIVE PERIOD.
AVERAGING MADE THIS QSO POSSIBLE!
AVERAGING MADE THIS QSO POSSIBLE!
JT65 VS. JT44JT65 VS. JT44JT65 HAS 3 MODES: A, B AND C. JT44
TONE SPACING (Hz) 2.7 5.4 10.8 5.42.7 5.4 10.8 5.4 dB ADVANTAGE 4.0 3.0 2.0 ---4.0 3.0 2.0 ---
SPECIAL CODES HAVE EVEN GREATER ADVANTAGE.
SPECTRAL 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!
LET’S YOU EVALUATE EME SYSTEM CAPABILITY.NOT GOOD FOR COMMUNICATIONS.ON 70 CM COPIED ECHOES WITH 200 W ON HORZ WITH
TROPO STATION.
STATION REQUIREMENTS STATION REQUIREMENTS
IT DEPEND ON HOW BIG THE STATION IS ON THE OTHER SIDE?
ON 70 CM – SINGLE LONG YAGI AND > 100 W. *** WANT TO ELEVATE (REALLY A MUST)! *** PREAMP AT THE ANTENNA (AND PA AT ANT). *** POLARIZATION ROTATION?
ON 23 CM – SINGLE LONG LOOP YAGI OR 5’ DISH WITH CIRCULAR FEED AND > 50 W. *** CIRCULAR POL GAIN + 3 dB!
PORTABLE EME – DL3OCH STYLE
PORTABLE EME – DL3OCH STYLE
BODO USES IC-706, HB TRANSVERTER WITH 100 W AND A 59 EL YAGI (5 m long & 18.7 dBd) FROM HIS CAR.
BESIDES DL, HE HAS OPERATED FROM 3A, HB0, EA8...
ZB2/DL3OCH IN GIBRALTAR ZB2/DL3OCH IN GIBRALTAR
BODO CHOSE TO USE JT44 FOR
THIS DXPEDITION..
YOU NEED A COMPUTER AND SOUND CARD
YOU NEED A COMPUTER AND SOUND CARD
SHOULD RUN 32 BIT VERSIONS OF THE WINDOWS OPERATING SYSTEM AND BE FAST ENOUGH TO HANDLE JT44/65 AND SEVERAL OTHER TASKS.
A 300 MHz PENTIUM OR BETTER WITH WINDOWS 98 OR PREFERABLY WINDOWS 2000 OR XP WILL BE MORE THAN SUFFICIENT.
NEED 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 REQUIREMENTS
FREQUENCY 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.
DOPPLAR 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’D
OTHER REQUIREMENTS CONT’D
MUST 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.
MUST BE ABLE TO TRACK THE MOON *** JT44 HAS BUILT IN TRACKING.
(DL3OCH has GPS & digital radio clock)
CONCLUSIONCONCLUSIONEME WITH JT44/65 IS NEW AND CHALLENGING.IT’S NOT JUST HAVING A YAGI, A100 W AND A COMPUTER!THE COMPUTER DOES NOT DO EVERYTHING FOR YOU!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).
WITH A WEAK STATION, ALL THE ABOVE PLUS MUST UNDERSTANDING HOW TO USE JT44/65 FULLY (EXCLUDE/INCLUDE, CLEAR, FOLD, FREEZE, CLIP, ETC.)
FOR 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…….
TO A LOT OF FOLKS,ESPECIALLY JOE, K1JTAND RUSS, K2TXB – MY JT44 MENTOR,AND TO ALL OF YOU FOR LISTENING.
QUESTIONS?
