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 Previous: FCC Suspends Amateur Licenses for Failure to Maintain Mailing Address |  Next: FCC Amateur Radio Enforcement Letters for the Period Ending July 18, 2006 |
By Bill Leger, N1UZ
n1uz@arrl.net
July 19, 2006
Field Day means lightweight, portable equipment. Putting a tower on a trailer makes it portable, but is it really lightweight? A few hams made such a tower on a trailer that met both requirements, all within a reasonable budget, and just in time for Field Day.
 The tower needed to be both lightweight and portable. Here is the trailer with the tower on its way to Field Day. |
 Jim Erickson, KA1GCN, on the winch. Paul Topolski, W1SEX, pushes down while Mark Kimmel, N1ZYZ, looks on. |
It was Field Day 2004, and I was on top of Mount Wachusett with the Montachusett Amateur Radio Club, talking to Paul Topolski, W1SEX, about how nice it would be to have an enclosed trailer with a couple of operating positions. After doing a lot of research, planning and pricing I determined that such a project could not be done for less than $7000, which was way out of my price range. The idea was put on hold until I came across Mark Kimmel, N1ZYG. Mark had a 40 foot tower in his backyard that he said I could have. I started to think about what my options would be with that tower. One option that was not open for discussion, due to aesthetic reasons, was installing it at my shack.
The Lightbulb Goes On
The idea occurred to me that it would be handy to have a portable tower available in the area for ARES, RACES or any other form of community service and, of course, contesting. After looking on the Internet for emergency trailers and antenna trailers, I came up with the idea of building a tower trailer. This could be built for a lot less money than an enclosed trailer. I set a maximum budget of $1000 for the project.
The first and most important item to find had to be the
mobile platform that the tower would be built on. It had to be long enough,
strong enough and in good condition. I found a 14 foot galvanized boat trailer
that would work just fine; the fact that it was cheap helped. After stripping
off all the boating features of the trailer, I covered it with 3/4 inch
pressure treated plywood, and then covered the complete surface and sides of
the trailer with aluminum tread plate (ATP). Now I had a good strong platform
to build the racks for the tower.
 The tower is now upright, but not fully extended. |
 Paul, W1SEX, checks out the tower at the Field Day site. It is now fully extended and ready to go! |
 Our trailer on a tower, fully extended and ready to use for Field Day. |
After careful measuring and checking of all the possibilities, Paul and I came up with a design for a rack to hold the tower that would require lots of welding. Since neither one of us had a contact who could do welding for little or no money, that idea was put on hold. I found a product called Speed-Rail that would use 1 inch galvanized pipe. This was the perfect solution for the rack, and it gave us flexibility just in case we needed to make some changes -- which we did.
Now came the problem of mounting the Cornell Dublier rotator and the pivot plate for the tower. We enlisted the help of Paul's son, Paul Jr, a junior at Montachusett Vocational Technical High School in Fitchburg, Massachusetts. Paul Jr designed and built the rotator and pivot plates under the guidance of his machine shop instructor. They also gave the tower its first coat of paint. Painting the tower was very important, since it had been sandblasted to remove all the old paint and rust.
The trailer would need some kind of outriggers for stability. We came up with a design of square tubing that would fit inside each other and installed it 120 degrees out of the rear of the trailer. The students at Monty Tech, along with their instructor, were able to implement our design along with the use of RV style scissors jacks.
Ready for Field Day?
One of the goals of this project was to have it ready for Field Day 2005. We picked up the tower from Monty Tech on June 13, almost two weeks before Field Day. Now the rush was on! We had already pre-assembled some of the components, such as the rotator extensions cords, halogen tower light, batteries boxes, tool box and an extra set of tail and directional lights. This was important, since the base of the tower was to be 4 feet behind the trailer.
One of our biggest concerns was the weight of the tower. With the antenna on it and the pressure on the tower frame as it went up, we wondered how much the boat winch could handle. After doing some research, we decided that the winch was fine, but there would be a lot of pressure on the frame of the tower. We installed a horizontal truss located on the side of the tower at the pivot point (as you look at it sideways) to distribute the load, taking some pressure off the pivot point. Each side has steel cables with turnbuckles.
A Learning Experience
An unplanned donation of three deep-cycle marine batteries from Fred Donaldson's, N1EZD, repeater, totaling almost 500 Ah, would give us extended emergency operating capability; these are located in the black boxes on the trailer deck. In the aluminum toolbox is a 400 A inverter, battery tender, wheel blocks, guy ropes and lots of spare parts.
This project proved again how diversified Amateur Radio really is. We accomplished a fairly good size project, learned a lot and met with some really nice people. As far as the $1000 budget goes, isn't it the American way to spend at least 15 percent more than you really want to on everything we do?
Bill Leger, N1UZ, an Amateur Extra, first received his
license in 1993 at the ripe old age of 47. He started getting interested in
Amateur Radio at age 12, when an uncle loaned him a Hallicrafters SX-101
receiver and he put a wire up in the backyard and started listening to
shortwave, mostly the BBC. Today his interests include RTTY contesting and
radio related projects at public events. Currently serving as president of the
Montachusett ARC, he lives in Fitchburg, Massachusetts.
| Previous: FCC Suspends Amateur Licenses for Failure to Maintain Mailing Address | Next: FCC Amateur Radio Enforcement Letters for the Period Ending July 18, 2006 |
