I was perusing eBay a few weeks ago and stumbled upon an interesting listing:
By Extending or retracting the 2 Antenna elements until you have reached the point of Resonance for the desired operating frequency. There by providing maximum forward power and little if any reflected RF power.
You have effectively built a custom cut to frequency dipole antenna each and every time you change frequency with out leaving the equipment operating position.
The Antenna is controlled by the flip of a switch, or could possibly be controlled by the micro processor in most modern day transceivers and could possibly track the VFO as you move up and down in frequency so it would always be at its resonant point.
A little intrigued, I e-mailed the creator, Frank McGinley, WB4NWV, to inquire about it. I asked how he developed it and told him that I’d be interested in doing a little post on his antenna design.
THE TITLE OF THE THE STORY IS HOW FAR HAVE WE COME.
LOCATION FORT BRAGG NORTH CAROLINA, UNIT OF ASSIGNMENT, 50TH SIGNAL BATTALION ( AIRBORNE ), FIELD TRAINING EXERCISE.
IT WAS DARK EXCEPT FOR THE LIGHT FROM THE STARS, THAT SHOWN THROUGH THE CLOUDS , IT WAS BITTER COLD AND THE WIND WAS HOWLING , THE RAIN AND SLEET WAS INTENSE, AS I STUMBLED THROUGH THE BUSHES TRYING NOT TO GET THE DIPOLE ANTENNA ELEMENTS TANGLED UP IN THE SAME BUSHES, UNSUCCESSFULLY I MIGHT ADD,THE TIME 23:45 HOURS I HAD TO CHANGE THE LENGTH OF THE DIPOLE FROM THE DAY FREQUENCY TO THE NIGHT FREQUENCY, AFTER A HECK OF A FIGHT TO LOWER THE ELEMENTS TO THE GROUND AND SPENDING 3 OR 4 MINUTES TRYING TO UNTANGLE THE HALYARDS, THE FLASH LIGHT WITH THE RED LENS HELD IN MY MOUTH AND MY GLOVES REMOVED, MY FINGERS SO COLD THAT THEY DID NOT WANT TO COOPERATE I WAS SHAKING SO BAD FROM THE COLD THAT THE LIGHT WAS HAVING A HARD TIME STAYING ON THE SPOT WHERE I NEEDED IT, MAKING IT EVEN MORE DIFFICULT TO UNTIE THE TANGLED MESS ALL THE TIME TRYING TO HURRY TO BE BACK UP ON THE AIR BY 24:00 HOURS
WELL AFTER WHAT SEEMED LIKE FOREVER I GOT IT BACK UP,AND RETURNED TO THE WARMTH OF THE RADIO TELETYPE SHELTER, AND BEGAN THE PROCESS OF CHECKING THE SWR, ONLY TO FIND THAT IT WAS TOO HIGH, WELL BACK OUT INTO THE COLD AND RAIN I WENT, THE ANTENNA WAS TO SHORT, ROUND 2 WENT ABOUT LIKE ROUND 1 NOT VERY SMOOTH, AS THE WIND HAD BLOWN THE ANTENNA ELEMENTS INTO THE BUSHES, IT TOOK ME QUITE A WHILE TO UNTANGLE THEM, LENGTHEN THEM AND PULL THEM BACK UP, BACK TO THE RADIO VAN, CHECK THE SWR AGAIN, NOT FLAT BUT GOOD ENOUGH, I WAS SOAKED AND FROZEN AND WAS NOT GOING TO TRY IT A THIRD TIME, NOT TO MENTION THAT IT WAS 00:24 HOURS,AND TIME FOR ME TO CHECK IN WITH THE NET CONTROL STATION, I HAD NO TRAFFIC AND THE RADIO CHECK WENT WELL, IT WAS NOW TIME FOR ME TO GET OUT OF MY COLD WET UNIFORM AND INTO A DRY WARM ONE, WELL AS YOU CAN IMAGINE I WAS NOT A VERY HAPPY CAMPER, AND TO THIS DAY I DO NOT ENJOY CAMPING OUT, THERE WERE MANY DAYS AND NIGHTS LIKE THESE THAT FOLLOWED , EXTREME HEAT,EXTREME COLD, WET AND SOGGY, BITING FLY’S, MOSQUITOES, YOU NAME IT AND ALWAYS THE SAME PROBLEM, TO LONG OR TO SHORT, KNEE DEEP IN MUD, UP AND DOWN BACK TO THE VAN, UP AND DOWN AND BACK TO THE VAN,AND NEVER COULD I GET THE SWR FLAT, CLOSE BUT NEVER FLAT.
TIME FLY’S WHEN YOU ARE HAVING FUN, SOON 20 YEARS OF FUN TRAVEL AND ADVENTURE HAD COME TO AND END, AND IT WAS TIME TO ENJOY H. F. RADIO AS A SERVICE, WELL THE MORE THINGS CHANGE THE MORE THEY STAY THE SAME, MY DIPOLE ANTENNA CUT FOR THE HIGH END OF THE BAND WITH A CLIP LEAD EXTENSION TO MAKE IT RESONANT AT THE LOW END OF THE BAND, WELL YOU GUESSED IT, BACK OUT INTO THE NIGHT IN THE SNOW IN MY BEDROOM SLIPPERS P.J.’S AND HOUSECOAT, NOT A GOOD THING, I KNOW I COULD HAVE USED AN ANTENNA TUNER OR COUPLER AS IT IS CALLED, BUT ALAS I AM A PURIST, AND DO NOT LIKE THEM, EVERY TIME I HAD TO DO THIS, I KEPT HAVING FLASH BACKS OF MY MANY FIELD TRAINING EXERCISES , THAT WAS WHEN IT STRUCK ME THERE, HAS GOT TO BE A BETTER WAY.
WELL I TRIED EVERY THING, G5RV’S, OFF CENTER FED DIPOLES, YOU NAME IT I TRIED IT, WAS I HAPPY, TO PUT IT MILDLY, HECK NO, SO IT WAS TIME TO PUT ON MY THINKING CAP, MY MIND WANDERED BACK TO WHEN I WAS THE NONCOMMISSIONED OFFICER IN CHARGE OF THE MARS RADIO STATION AT FORT BRAGG, WE HAD A DIPOLE MADE FOR COLLINS BY HYGAIN THE TD-1 IT WAS MADE OUT OF TAPE MEASURE TAPES, IT WAS A POOR DESIGN, IF YOU USED MORE THEN 100 WATTS IT WOULD ARC INTERNALLY , BUT THE CONCEPT WAS THERE, CHANGE THE DESIGN SOME ADD A 13.8 VOLT D.C. MOTOR, SOME LIMIT SWITCHES AND A CONTROL BOX AND , YOU HAVE A MOTORIZED ONE HALF WAVELENGTH DIPOLE THAT CAN BE REMOTELY ADJUSTED FROM INSIDE THE RADIO OPERATOR’S LOCATION, WITH NO NEED TO SEE IT OR GO OUTSIDE TO ADJUST THE ANTENNA.
YES 1.8 MEGAHERTZ TO 55 MEGAHERTZ AND EVERYTHING IN BETWEEN WITHOUT COMPROMISING, PERFECTLY FLAT SWR 1 TO 1, AND NO NEED FOR THE INFAMOUS ANTENNA TUNER, IN THIS AGE OF ALL MODE ALL FREQUENCY H.F. TRANSCEIVERS, THERE WAS A NEED FOR AN ANTENNA THAT WOULD COVER THE ENTIRE H,F, SPECTRUM WITHOUT COMPROMISE, MANY THOUGHT THAT DAY WOULD NEVER COME, ARE YOU SICK OF DUMMY LOAD ANTENNAS AND ANTENNA TUNERS, GENERAL COVERAGE TRANSCEIVER MEET GENERAL COVERAGE ANTENNA, I GIVE YOU THE AMAZING TUNE-A-TENNA.
Frank has a fascinating story and I salute his service to our country.
Pretty neat. But… well, $25,000 is a lot of money for an antenna. What do you get? A patent (7,286,100B1), trademark (3,336,489), domain names, and a few prototypes. According to the eBay listing, Mr. McGinley believes that the right buyer could base a business around this antenna design and manufacture them for about $300 each:
Our best estimate, the cost to produce the final product for sale should be around $300, Possibly lower.
Our best Estimate of the retail price of the semi-auto version would be $825, which equates to $525 per unit. If you advertise wisely on Ebay, Qrz.com and QST Magazine you should have no problem netting $500 per unit profit, possible more?
Our best estimate of the retail price of the auto version would be $1,225 which equates to $700 net per unit possibly more?