Demise of the 80/40m Dipole

Sad to say, I recently lost my 80/40m trap dipole. Which is too bad, because it was a good antenna. I used this antenna from four different locations in Georgia: Gwinnett, Floyd, Walton and Fulton counties. I made thousands of contacts on this antenna. It had been the first antenna I put up at Floyd and Walton counties, and the only antenna at Fulton county.

It was last up at the parsonage in Fulton county. Apparently a group of teens was doing some volunteer work near the parsonage. They saw the rope tied off to the parsonage fence and thought it was something other than it was, so they untied it.

After this, half the antenna fell down to the ground and was left there. When the landscapers came by to mow the grass, they ran over it....

So, about 80 feet of rope, insulator and one of the traps was completely destroyed. The other half of the dipole is still intact, up in the trees. But most of one element is gone -- clearly the landscapers threw it away.

Plan is to design an 80/40/20m trap dipole, using traps made with coils and capacitors, since they have much higher Q than the coax cable traps. I'll also place the traps on frequencies well off the operating frequency.

Dipole Back Up!

I wrote back in May that my 80/40m dipole had fallen down when a tree branch broke off and came through the antenna.

While there was no real damage, it did dislodge the rope anchor I had cast over the tree. Because it is so difficult to cast a line into the trees when the foliage is out, I had to wait.

It was fortunate, however, that I did wait. During the summer storms, this same tree shed a couple more large branches. Well, the leaves have thinned out considerably from the trees, and I've actually been out in the woods a couple of times to cast a new line.

Those sessions didn't end well. You see, I'd go out with a weight made of a 1/4 to 3/8" bolt and a few nuts, and on the first cast, I'd lose them. They came sailing off the end of the line, never to be found.

Assembled parts for the antenna launch weight

As I wrote about the Mark III Antenna Launcher, losing weights is inevitable. Given the beautiful fall weather we had this weekend, I decided I was not going to have my antenna raising session interrupted by a single lost weight.

Normally, I'd recommend you construct these antenna weights with hardware you're not likely to use for anything else. This likely means old, corroded nuts and bolts that you've taken off some old assembly. However, I did not have much of this kind of hardware on hand at the Micro-Shack.

Technique for jamming nuts together

Time to fight back with numbers. A quick trip to the local home improvement store found 100 1/4" nuts and a dozen 1 1/2" long 1/4" bolts for about $8. The plan was to jam on as many nuts as the bolt would allow. This would make for a reasonably heavy weight, but one that would fit well in the slingshot pouch.

Assembly is easy. Simply screw the nuts on to the bolt as far as they will go, and repeat. I managed to get six nuts on the 1 1/2" bolts, although I did have one overachiever bolt that received seven.

The finished product. A dozen weights, most with six
nuts, one with seven.

Once the nuts are on the bolt, but loose, take a couple of wrenches and jam them down on the end of the bolt, and then one against the other. Make them tight enough that they won't go flying off when launched into the air.

Less than 20 minutes later, I had a dozen antenna weights. Filled with confidence, I marched outside fully prepared to lose numerous weights in order to get the dipole in the air.

Naturally, given my readiness for sacrifice, I managed to get the line over the tree branch on the first shot. I didn't lose a single weight. Well. I am now prepared for the mid-winter antenna raising season.

I am very happy to have this dipole back up. I have missed it all summer.

Six Knots Every Ham Should Know

In working with wire antennas, I'm thankful my parents enlisted me in the boy scouts. How else would I have learned all these useful knots? Every amateur radio operator should know how to tie these six knots:

• Bowline - an extraordinarily useful knot. Anywhere you need a knot that won't slip, won't tighten down and is very strong. I use this one everywhere -- when tying ropes off to insulators, bringing wires through insulators, tying ropes to carabeaners, etc. If you learn no other knot, learn this one.
• Square Knot - Got two hanks of rope, neither of them long enough for the job, join them with a square knot. While it won't go though pulleys, it will go over branches with a tug our two. best way to join ropes of roughly the same size.
• Sheet Bend - so, how do you tie your hauling line to the fishing line you've managed to get over that tree? Square knot doesn't work so well when one end is a lot smaller than the other. The Sheet Bend is the answer. Just remember that the larger line gets the "U" and the smaller line is the "X".
• Taut-Line Hitch - need to adjust a rope to a modest tension, but don't want to keep re-tying? The Taunt-Line Hitch is perfect. You can slide this knot considerably to adjust tension. Just don't use it for anything structural, like guy wires, since it can slip down under enough tension.
• Two Half-Hitches - Have a free end of a rope you don't want to flap around loose? Two half-hitches is the choice. I often use it to secure the free end after a Sheet Bend.
• Clove Hitch - Be careful with this one. It works well if you tie to a fixed post that can't rotate. Don't try to use it to raise a mast or left a boom -- with a smooth rope it may turn and then come loose. 

Learn these knots inside, you'll want to have them memorized for when you are ready to use them out in the field or woods. Enjoy.