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- LOOP ANTENNA CALCULATOR
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- by GEORGE CSAHANIN JR.
- WB2DYB
- 7 JULY 1986
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- THIS PROGRAM WILL CALCULATE THE VARIOUS PARAMETERS OF THE W5QJR SMALL LOOP
- AS DESCRIBED IN JUNE 1986 QST. THE FORMULAS ARE FROM TED HART'S BOOK ON SMALL
- LOOPS. THIS VERSION WILL CALCULATE THE CAPACITY, VOLTAGE, Q, BANDWIDTH. ETC.
- FOR THIS FINE ANTENNA. TED HAS NOTED THAT THE ACTUAL BANDWIDTHS ARE GREATER
- THAN THE FORMULAS CALCULATE, AND IN FACT I HAVE FOUND THIS TO BE TRUE WITH MY
- LOOP. MY BANDWIDTH IS ABOUT 2.2 TIMES WHAT THE FORMULA SHOWS IT TO BE. AT ANY
- RATE THIS IS A FINE ANTENNA, AND WORTH A SHOT IF YOU HAVE A SPACE PROBLEM. MY
- INSTALLATION IS IN MY ATTIC, WHERE IT ACTUALLY PERFORMS NECK& NECK WITH MT
- DIPOLE, OR VERTICAL. IN FACT MY FIRST QSO ON IT WAS ON 40 METERS FROM MY QTH
- IN TEXAS TO JAPAN! THE THING DIDN'T EVEN HAVE IT'S MOTOR DRIVE YET, IT WAS
- JUST SITTING ON THE BOOKSHELF NEXT TO ME IN THE SHACK, BAREFOOT, 100 WATTS,
- AND THIS JA7 CAME BACK TO ME. NOISE IMMUNITY ISN'T WHAT IT IS CRACKED UP TO
- BE. IT ISN'T WORSE, JUST NOT BETTER.
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- TED HART SELLS A CAPACITOR, WHICH I RECOMMEND. I GOT A STEPPING MOTOR FROM
- HERBACH & RADEMAN FOR $3.50. IT HAS LARGER STEPS, BUT I HAVE NOT HAD ANY
- PROBLEM WITH IT YET. WITH THE CAPACITOR THAT I GOT FROM TED, MY 3 FOOT
- DIAMETER LOOP (WHICH I DID HAVE TO PRUNE A BIT) TUNES FROM 6.950 MHZ TO 14.250
- MHZ. I GAVE UP PRUNING FURTHER, AS THIS DID ALL I NEEDED. IF YOU DO ANY
- SNOOPING AROUND THE INTERNATIONAL BROADCAST BANDS WITHIN THIS IS A GREAT FIND.
- AS FOR MOUNTING, I HAVE IT HUNG FROM THE 2X4'S IN THE ATTIC WITH NYLON ROPE.
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- IF YOU ARE AN ANTENNA EXPERIMENTER, OR IF YOU JUST HAVE A PLAIN OLD SPACE
- PROBLEM, TRY THIS ONE. FOR THE COST OF THE CAPACITOR, SOME SOLDER, AND SOME
- COPPER TUBING IT WILL PROVE ITSELF TO YOU. AS FOR THE FORMULAS, AND THIS
- PROGRAM WHICH IS WRITTEN FIRST IN BELIEVE IT OR NOT, COMMODORE BASIC,
- TRANSLATED TO MBASIC, AND FORTHER REFINED UNDER BASICA, THEN COMPILED WITH
- TURBOBASIC, TRY THEM. IF YOU NEED THE BASIC FILE DROP ME A NOTE THRU THIS
- AMATEUR RADIO BBS, OR THRU COMPUSERVE, OR DEEP THOUGHT IN AUSTIN, I'LL GET IT
- FOR YOU. THIS PROGRAM IS NOT FOR SALE, AND IS FREE FOR THE USE OF ALL ENGAGED
- IN NOT FOR PROFIT ACTIVITIES, RELATIVE TO NEWLOOP.EXE, OR NEWLOOP.BAS
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- GEORGE
- 512-331-9568 HOME
- 512-476-3636 WORK
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- PS- ALSO I HAVE INCLUDED NULOOP FROM ANOTHER SOURCE. IT DOES THE SAME, BUT DO
- NOT BE CONFUSED BY THE DIFFERENCE IN TUNING CAP RESULT. MINE IS SHOWING TUNING
- CAP MINUS THE DISTRIBUTED CAPACITANCE. NULOOP ALSO WANTS DIMENSION IN LENGTH
- OF A SIDE FOR AN OCTAGON, NEWLOOP(MINE) WANTS LOOP DIAMETER.
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- GEORGE 72060,3640/75706,577
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