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I Love Field Day

06/04/2008

I haven't missed a Field Day completely for over 20 years, so when the American Medical Association (AMA) meeting fell on the entire Field Day weekend, I was devastated (okay -- seriously disappointed). I decided that I would operate one way or another and began my plans. The AMA meeting was to be held at the Chicago Hilton. I considered setting up in Grant Park across the street from the hotel, but I would have very little time to operate and could not leave the station unattended between opportunities. Unlike most hotels in downtown Chicago, the Hilton has windows that open about 4 inches. This gave me the "opening" I needed!

What kind of antenna should I use? I had a commercial apartment dweller's antenna that had never been used. It is essentially a very short collapsible whip mounted on a large base coil. I assembled it and tried it out. Tuning was difficult and dependent upon the mounting location. It would probably work fine on a single band, but since I anticipated multiband operation, another solution was needed. I decided to use a dipole and a small antenna tuner. Safety was the primary consideration and a low visual impact (OK -- stealth) was also a consideration. Although I knew the activity was harmless, I wasn't sure I could convince the hotel staff of the value of my participation in this emergency preparedness exercise.

After careful consideration, I decided to use a Sunny Day 20 collapsible fishing pole as a support. I used some scrap plywood and U-bolts to form a clamp. I planned to attach the center of the dipole to the end of the Sunny Day and use the RG-58 coaxial cable to act as the safety line securing the structure if the clamp should fail. Next, I considered the antenna itself. I wanted to minimize the weight as much as possible, so I decided not to use a balun at the feed point. A thin piece of Plexiglas was formed into a center support and the coax was attached with screws and wing nuts. Small cable ties were used for additional support. Small gauge stranded speaker wire formed the dipole elements. My plan was to drop the element attached to the inner coax conductor from the center support at the end of the pole. If I angled the pole down from the window, I thought I would be able to widen the angle between the elements bringing the shield side of the dipole back to the window. This would be a compromise antenna, for sure, but isn't that what field day is all about?

Finally, I assembled the portable station. I knew that there would be little time to operate, so I mounted the radio, a Yaesu FT-857D and a small manual antenna tuner on a plastic kitchen cutting board. This allowed me to mount power connectors, microphone and straight key on the board also. The result (after trimming the board with a circular saw) was a portable station that could be placed in a small suitcase and set up within a minute or two at the operating location. My power supply would be a 25 A switching power supply using commercial power. Limited space and resources made batteries or a generator impractical and my goal was to operate, not compete.

When the day came, so did Murphy. In my haste, I left the Sunny Day at home. Luckily, I realized my mistake before reaching downtown Chicago. A quick stop at Lowes netted an 8 foot, ½ ×1 inch wooden stick. The flat sides made it easy to use an adjustable wood clamp to secure the antenna and support to the window sill. Several cable ties were used to attach the coaxial cable. Field Day was a go!

My room was located on the 16th floor, with brick walls on three sides. This "canyon" was open to the east. As an elected delegate to the AMA, even on field day my first priority is to represent the physicians of Indiana developing policy and considering national scientific, ethical and economic health issues. Our meetings leave very little personal time. Nonetheless, I was able to put my station on the air for about an hour during the day on Saturday and later through the night. I made 21 contacts from Maine to Georgia. Several of my physician colleagues stopped by to marvel at my ingenuity and question my sanity. Twenty-one contacts do not sound like much, but making the first contact was the challenge. The next 20 were some of the sweetest contacts I remember. I did not rack up a big score, but I was able to deploy and operate an amateur station under very difficult conditions. Was it worth all the effort? -- you bet!

Photos courtesy Stephen Tharp, MD, K9MD

Stephen Tharp, K9MD, first learned of ham radio as an eighth-grader in Indianapolis, Indiana in 1965. It wasn't until medical school in 1973, where he met Bob McDowell, WA9LHE, that he passed his Novice exam and became WN9QGY. He soon upgraded to his Technician ticket and became WB9QGY. He married his wife Susan in 1976 and, on their way to meet her parents in Minnesota, detoured to Chicago to pass his Advanced exam. Stephen earned his Extra class license in 1994 and obtained his vanity call, K9MD, in 1996. It was only afterwards that he realized that non-hams would see his vanity license plate and believe him to be a veterinarian. Stephen and his wife live in Frankfort, Indiana, and the best part of living there is not that we are the "home of the Hotdogs" (yes, our school team is known as the Frankfort Hotdogs), but that we are 3 hours from Dayton!

 

Stephen D.Tharp, MD, K9MD



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