Spring 2006 Issue


Greater Range at 100,000 Feet


“To get greater range on VHF, get your antennas higher.
Go climb a mountain.”—The Old Timer



By Jerome, K5IS, and Bobette N5IS, Doerrie

There’s not much in the way of mountains on the high plains of the Texas and Oklahoma panhandles. The local weak-signal operators joke about the interstate overpasses being 20-dB hills.

The ARRL Antenna Book lists the formula for line-of-sight radio horizon as D (miles) = 1.415 times the square root of the antenna height in feet. An altitude of 10,000 feet yields a range of 142 miles.

We considered erecting a 10,000 foot tower, but quickly discarded that idea. A small private airplane could easily reach this altitude and would be much cheaper than the tower. We have operated radios from the back seat of an airplane in spite of the engine noise. We knew there had to be a better way, though.

Operating on the summit of one of the 14,000 foot mountains in Colorado gives a similar communications range. However, weather factors cause operator discomfort.

If radios can be carried to 100,000 feet, the range becomes 447 miles, providing the possibility of stations 800 miles apart being able to communicate for a few minutes. Placing the antenna and radio equipment at 100,000 feet over Booker (northeast corner of the Texas panhandle), the communications range could reach hams near Dallas, Albuquerque, Denver, and Kansas City. The challenge becomes one of how to climb to 100,000 feet and still maintain operator comfort.

The solution: Use a weather balloon to carry the electronics aloft.

In the fall of 1992, Bobette, a high school physics teacher, started the Perryton High School Reach for Space program as an enrichment project for her science students. Our first balloon flight was in the spring of 1993. In this article we describe some of our experiences and tell what we have learned over the past 13 years from flying “weather” balloons up into the thin air of near space.

First We Thought
We Needed Balloons

It began when Bobette attended a presentation on remote sensing at the state science teachers conference. A contest called SkyView, sponsored by the Texas Space Grant Consortium, involved taking pictures from a platform in the air—either a balloon or a kite. It had obvious amateur radio applications, because the camera probably would need radio signals to trigger it.

In 1992 at a hamfest in Amarillo, Texas, we found a surplus dealer with a case of weather balloons. A deal was made and we had balloons. We knew nothing about lift capacity, ascent rates, burst altitude, tracking, recovery, amounts of helium needed, regulations, or the effect of age on latex balloons. We had balloons and we began our journey on the learning curve.
 

Photo A. It takes a committee to prepare the payload, especially when there are problems. (All photos courtesy the authors)

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