antenna circuit

Antenna Circuit, VHF - The Little Sam

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One of the most interesting items that I have ever produced was the "Little Sam" antenna circuit. I orginally produced it as an antenna circuit plan that was sold in Jacksonville Florida under a company by the name of "Samtronics Import" back in the early 90's.

I went on to, pull the plans, and manufacture the unit using a young Pastor in Hephzibah, Georgia his wife and three children to mass produce them for me. Each unit was pruned ( Resonated to the customers frequency - by me ) prior to shipment. When the plan was originally sold it included instructions for pruning the unit in Laymans terms that I have reprinted below what was included in the original plans. Enjoy, John.

ALTHOUGH THE "LITTLE SAM” WAS DESIGNED TO FUNCTION IN THE TOP END OF THE FM BAND, BY DECREASING THE AMOUNT OF TURNS OF ITS COIL AND RE-PRUNING ITS END #.035 COPPERWELD WIRE BY CLIPPING, ITS FREQUENCY RANGE CAN BE INCREASED WELL INTO THE TOP END OF THE VHF BAND. BY THE SAME TOKEN, INCREASING THE AMOUNT OF TURNS WILL TAKE IT BELOW THE FM BAND AND BOTH CONVERSIONS CAN BE DONE THROUGH EXPERIMENTATION.

THE ANTENNA IS A LOW PROFILE THAT MULTIPLIES A TRANSMITTER SIGNAL X 2 OF ITS NORMAL OUTPUT POWER AND/OR WHEN ADDED TO A RECEIVER ADDS ROUGHLY A DOUBLING OF THE SIGNAL INPUT WHEN COMPARED TO A SINGLE WIRE ANTENNA OF THE SAME SIZE.

TO CONSTRUCT YOUR "LITTLE SAM" ANTENNA, DRILL A HOLE AT DIRECT CENTER OF EACH END OF THE 1 1/2" SECTION OF 5/16" WOOD DOWEL USING A # 57 DRILL BIT. TAKE THE PIECE OF .062 DIA. WIRE YOU HAVE CUT TO 5 3/4" AND USING A PAIR OF WIRE CUTTERS, CRIMP SLIGHTLY ABOUT 1/4" OF ONE OF ITS ENDS. SCREW THAT END UP INTO ONE END OF YOUR DOWEL UNTILL IT SEATS. TAKE THE SMALL 1/2" SECTION OF .062 WIRE MENTIONED IN (C) AND CRIMP 1/4" OF ONE END OF IT AND SCREW THE CRIMPED END UP INTO THE OTHER END OF THE DOWEL. LOOP AND SOLDER THE END OF A SECTION OF # 22 MAGNET WIRE AT THE END NEAREST THE DOWEL ON THE 5 3/4 " SECTION AND PULLING TIGHT, START WRAPPING YOUR TURNS AT A POINT 1/2" FROM THE LEFT END. WRAP EXACTLY 17 TURNS, BEND TO THE RIGHT HAND SIDE AND LOOP AROUND THE SMALL 1/2" STUB-OUT AND SOLDER. TO THIS STUB-OUT, SOLDER ONE END OF THE 6 3/8" SECTION OF .035 COPPERWELD WIRE MENTIONED IN (B).

PLACE YOUR 2.1/2” SECTION OF 3/8" HEAT-SHRINK DIRECTLY OVER THE COIL, COVERING EACH END EVENLY AND SHRINK USING A CIGG LIGHTER OR HEAT GUN. ADD YOUR CONNECTOR TO THE OTHER END OF THE .062 SECTION OF WIRE. YOUR ANTENNA HAS NOW BEEN CONFIGURED FOR THE FM BAND. IT HAS A SINGLE RESONANT FREQUENCY AT THIS POINT OF BETWEEN 118 TO 120 MHZ.

TO PRUNE TO THE FM BAND: IF ON A TRANSMITTER: CONNECT TO YOUR TRANSMITTER, TURN TRANSMITTER ON AND USING A F.S.M., START CLIPPING THE END OF THE ANTENNA WIRE (.035) UNTILL MAXIMUM POWER OCCURS ON YOUR F.S.M.. STOP WHEN IT PEAKS. FURTHUR PEAKING CAN BE DONE BY INSTALLING A TRIMMER CAPACITOR OF BETWEEN 1 TO 50 PF ON THE OUTPUT OF YOUR TRANSMITTER IF IT HAS ONE OF A FIXED VALUE. ADJUST TRIMMER AND CLIP ANTENNA IN 3/32"INTERVALS UNTILL RESONANCE OCCURS INDICATING MAXIMUM TRANSFER OF R.F. ENERGY. IF ON A RECEIVER, CLIP UNTILL MAXIMUM SIGNAL STRENGTH IS INDICATED ON THE METER OF YOUR SIGNAL STRENGTH METER. IF NO METER, TUNE TO TRANSMITTER ABOVE BEFORE INSTALLING ON RECEIVER. AN ANTENNA THAT IS TUNED TO A TRANSMITTER IS FUNCTIONAL TO YOUR RECEIVER.

antenna circuit, the little sam fm/vhf custom antenna circuit
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