AK6R Tower Trailer
The Tower trailer is about 30 years old and has a 58 foot Tristao tower mounted on it. It was previously used to hold a portable six foot microwave dish so it is plenty sturdy. I estimate 18 square feet antenna capacity. When we repacked the bearings on the trailer, we found out the axles and hubs were from a 1953 Chevy truck. Took us a while to find a hub for the spare tire that would match.
The tower is raised to 90 degrees with a hand winch with 8:1 reduction. It raises quite easily but you know you have put some work into it after you are done. The mast extends 13 feet out of the top of the tower making the very top at 71 feet from the ground. The mast is .25 inch steel and works well with two large antennas. I have used the F12 C31XR and mono banders for 40 and 20 (both at the same time and individually) on the mast.
The Tower is extended by motorized winch with positive pulldown. I have a 4000 Watt generator and 3 jerry cans on the trailer (I take them off during generator operation). The winch has a short 4 foot pigtail that temporarily plugs into the generator. I also have a keylock for the winch control on/off and limit switches at the top and bottom of the tower which shut off the up/down control. (Safety first here!). It takes about 90 seconds to raise the tower.
In order to get more versatility from the tower I added a boom mount at the top (side) of the second section which is at 38 feet. This is a perfect height for 10 meters of 15 for domestic contests. I have also had good luck with 15 fixed on Europe with this height. In June 2001, I modified the boom mount to accept a swing gate which rotates 270 degrees. Previous to this new addition, the antenna was fixed in direction (usually NE to Europe or the east coast of the US for domestic contests). Now I can swing the beam from VK to SA for different openings.
Also at the 58 foot level (top of tower), I have a 5 foot yardarm with pulley and 120 feet of halyard. This point is used to support a G5RV, an 80/160 dipole or serve as the end of one of these antennas when used with another tower which supports the opposite end.
It takes about 3 hours to setup the antennas on the tower trailer from scratch. Most of the time is putting the elements together on the tower tilting it to about 45 degrees and then adding the remaining elements. Hygain beams are very easy to do, Force 12 are more complicated but I have figured out a fast temporary replacement for the rivets which makes the operation much easier.
Here are some combinations of antennas I have used with good results:
1. F12 C3E at 38' and F12 C3E at 66' with WX0B Stackmatch(TM) to pick in phase, top or bottom. (Note I used this configuration in 2000 Field day and never left the call frequency once! - this was on 20 meters where the antennas are roughly equivalent to a 60 foot six element 20 meter beam, but obviously much easier to handle). You also get 10 and 15 meter operation as well as WARC bands (sans 30). The WX0B Stackmatch(TM) is mounted at the 58 foot level and 25 feet of RG-213 feed each antenna. See Field Day 2000 for a photo.
2. Same as above but with F12 C4SXL (with 2 element 40 M beam). Only need to add 5 foot phasing cable to one of the antennas to match up driven element wave timing. 80 meter dipole supported from yardarm.
3. F12 240X at 66 feet, Hygain 204BA at 59 feet and Hygain 155CAS at 38'. Real killer combo. My DX contest setup. See CQ WPX CW 2001 for a photo.
4. For single band efforts such as the ARRL 10 meter contest I two modified KLM 610's (extended boom by 5 feet, single driven element, direct feed with CALAV 1:1 balun) phased with the WX0B Stackmatch(TM). Bottom antenna at 38', top at 66 feet. ( I use a jack-mast of 5 feet attached to the center of the lower antenna to hold the truss cable).
5. For the 1999 Sweepstakes I used a Cushcraft 204-CD, four element 20 meter beam above a Hygain TH3 tribander. See the 1999 Sweepstakes photo.
6. For the JA contests I have used the F12 C31XR on the top and the KLM 610 fixed on JA land (310 degrees from here). See the photo here.
More to come I am sure........