KC8AON's QRP PROJECTS

"KC8AON TACTICAL DELTA LOOP"

A LOOP THAT ISN'T A LOOP

GREAT DX ANTENNA !

Covers 10 thru 80 meters with use of a tuner

Antenna is by-directional broadside to the loop when hung vertical

Works well at low heights

Uses 1/3 the horizontal space as the doublet it is made from

This is one antenna that I tried one day when the bands were really in good shape and DX was booming in from all over Europe. All I had up at the time was a 135' balanced line fed doublet that favored north and south signals, but I wanted something I could get up quick that would work in the direction of the DX and wanted something that was fairly directional and worked more than one band. I had a standard G5RV that I had put together to use while camping, but figured it wouldn't be a real good DX antenna. My property is 108' deep and 260' long with power lines running along the front section, so my big doublet runs through the long side at the back of the property to keep it away from the power lines. Getting a wire antenna up that would work east and west was going to be a real trick with that power line in the way ! I went outside and started looking around and almost put up a wire vertical, but figured that would need a real good ground to work well and quickly scrapped that idea. My mind kept thinking of the G5RV I had already made, and I looked at these 2 trees on the west end of my property that were about 50 feet apart with one to the north and the other to the south. They were in the right direction, but not quite far enough apart for the G5RV. Then I thought about a delta loop and started looking around for materials to build one with and then it hit me. Why not just fold the G5RV into a triangle with the ends meeting in the middle at the top of the triangle and the feedline coming off the bottom of the triangle. I sat down and sketched it out on paper so I could study it and think this thing through and almost decided to bond the ends of the wires together where they meet at the top. Then I thought, if I leave them unconnected I can work some of the low bands and still have a directional antenna for the higher bands. So, I removed the end insulators and slipped an insulator on each leg to act as the top corner tie points for the support rope and then reinstalled one of the end insulators with each wire attached to the oposites ends of it. This made the G5RV look like a delta loop that was 34' on each side, except that it was not a loop at all since the top wires did not connect to each other in the middle. (refer to the diagram above for more detail). Then I went back out to my trees and shot a line across both of them with a fishing rod and hoisted some white plastic coated clothes line rope with the loop attached. I managed to get the top of the loop up about 40' with the feepoint about 8' off the ground, then I ran the balanced feedline toward the house almost at a right angle to the loop and suspended it from another small tree close to the house. Then I attached the coax to the balance line through a 1:1 choke balun and into the house. Connected it to the tuner and tuned around on 20 meters - WHOW ! The signals I heard were very strong ! Checked the SWR on 20 and had to use the tuner, but it tuned up just fine. Worked several stations that evening on 20, 17, & 15 meters, then when the DX faded away I switched to 40 meters to see how it worked there. Worked the west coast on 40 for the first time (Washington State) and then tried it on 80 meters, and to my supprise, it loaded there too and worked quite well ! So now I had a good directional antenna that shot my signals in the direction I wanted, and worked several bands including 80 meters, and it only required 34' of horizontal space to do so ! It's a shame that a windstorm took it back down about 6 months later, but when the bands start getting better, I'll put up another one ! Oh yeah, the reason I call it "tactical" ? Tactical is when you put something up in a hurry to get the job done quick, and this one did !

73