I finally got my G5RV antenna from Maple Leaf Communications up in the air. I live among many very tall oak and pine trees, easily 100 -140 ft high. A number of them are right outside my shack… so, what to do? Use nature-made towers!My son, Jon, is an avid bow-hunter but he was apprehensive at shooting arrows where we have neighbors within the potential landing zone! I’m not much with a sling-shot so I turned to a tennis ball launcher. I looked at WB6ZQZ's website (http://www.antennalaunchers.com) and he’s got a good product. Being cheap but ignorant on constructing his launchers, I surfed eBay and bought the less expensive Wind Demon, the 2.5″ model (shown on left). After experimenting with regular tennis balls, opened with an eXacto knife, stuffed with 22 pennies to make them weigh 4 ozs, I ordered three made by WB6ZQZ. He uses sand and hot-glues the slit back with a loop made from thick fishing line. We found that the ones with sand work best.
The key thing that we found was how the fishing line was stored for «launch». I used 300 yards of braided fishing line (color red) but purchased a Saunders bow-hunting reel so that the bail would hold this much line. Simple math: 150 ft. tree needs that much to go up and that much to come down on the other side of the tree. My Shimano fast-cast open-face reel would be super-better to rewind the line but would only hold about 100 yards of line. A visit to Lowe’s gave me two connectors of PVC that would slide over the barrel of the Wind Demon. A Dremel tool and a flat piece of wood helped attach the Saunders reel with two metal screws. You can see the general idea in the picture on the right. The metal knob on the black PVC pipe is where the compressed air goes.
Here are pictures of the two target «end» trees: two tall pines for the ends of the G5RV and a center one of unknown species (it was «there») below (see text). Also shown is a short video-clip of Jon firing the Wind Demon and my (wobbly) attempt at tracking the tennis ball and fishing line.Once we shot the fishing line over the tree… and Jon hit an optimal throw high up at the top on three of four shots… it was time to pull the fishing line back over with Dacron nylon cord (3/32″ dia.) back over the tree. When we finished retracting the fishing line with the nylon cord, we needed to attach a pulley. The back-end of the length of cord needed a tie-off point which we opted to use cleats screwed into the side of the tree.
The stainless steel pulleys and cleats were purchased at my local Lowe’s store. They’ve got several sizes of pulleys and cleats but I just went with a fairly small pulley that I thought would work best with 3/32″ Dacron rope (purchased on eBay).
We tied-off the pulley and strung a new strand of Dacron rope through it before retracting the pulley’s tie-off rope back up the tree. This will give me the ability to more easily repair the G5RV or put up other dipole designs when needed.
Shown below are pictures illustrating the tree cleat with excess Dacron rope bundled (for when I need to lower the pulley!) as well as the pulley assembly.
Once each line was put into place via the pulley system, we tied the ends of the G5RV---very well made by Maple Leaf Communications, by the way---to a rubber «bungie» strap. This will allow the trees sway to have play and not stretch the wire dipole. We did the same thing for the center support tree, visible in the video clip. It was a learning «dance» that we had to do to get the full 102 ft. antenna up… the proximity of the center support tree was not centered exactly between the two end trees in a direct line. We effectively had to pull on the center support with the RG8X coax as we pulled up on the respective ends to navigate the G5RV «around» the center tree’s lower branches. We learned some things from this, however, in that it’s better to get the pulley lines placed around troublesome branches than just take the first «good» shot as we did. However, this was a relatively easy «launch» of a dipole and it’s up about 100 ft.While the G5RV was «up» the air, it actually took me a few weeks to test it «on» the air! Our house is on the market and I am being very careful about having an excess of wires and so forth not being in their correct «place». I had ordered a custom external conduit box from KF7P as well as a few Polyphaser lightening dissipation modules so I waited a bit. I then recalled that I had also ordered a Comet CTC-50M Window/door feed-thru jumper from Cheapham. So, I made a temporary arrangement with the G5RV coming in under an exterior door. My favorite leather chair and ottoman, coupled with a lap board from Levenger, has become the location of my Icom 706, LDG IT-100 auto-tuner, and MFJ Mighty-Lite power supply. I have a netbook running Linux Mint 10 on the right side of the lap board and a notepad and pen on the left. With about two hours of operations across two days, I worked northeast Texas with ease and the Atlanta area’s QRP Net with 59 signal reports. I was able to chat with my friend, Arnold KC4ZUA, with ease on this Tuesday night net… even though I was cheating by running 100 watts!
So this dipole is off to a good start. We’ve got snow falling in Starkville as I write this so it will be next week before I get the external steel box installed for running the R8X into the shack as designed. I can then install my Wellsbrook ALA-1530+ loop for Rx, the Perseus SDR receiver, and get the Flex 3000 up and running with the Ameritron 811 stoking the fire. But, for now, this little Icom 706 running barefoot into the G5RV is fun. The work ahead will be fodder for future posts. Sounds like hot chocolate could find a place by my leather chair while the snow falls!