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Random wire part II......

WX2MIG

WX2MIG

Still Alive & Well
Dec 10, 2008
730
5
28
39° 19' 23" N X 74° 36' 30" W
A couple weeks back during a severe thunder storm, my random wire antenna broke.
This morning I slapped together a new one, it's a little shorter than the original, but I did that to try and keep it out of the foliage.
Evidently I hit on a bad length, the original would tune up great on 75/80 meters, and also do a good job on 40 meters. I could never get it to tune up on 20, 17, or 10 meters, but it would do on 12 and 15, not great, but ok.....

This new one does 75/80 just as good as the original, but it's the only band it'll tune up on, I can't get below a 2.5:1 on 40 meters, and forget about it on anything else....
I'm not really concerned about the upper register from 17 to 10 meters since I get that on the Big Stick, I have a 20 meter dipole that does very well, but I 'd like to get 40 meters out of this wire since I took down the 40 meter dipole I had up....
Guess my next move is to make another coil, and maybe next winter after all the trees are bare I can get a rope over a different branch and add some length to this thing......
 

I have a central ground for all my amateur radio equipment, all my radios and antenna tuner are tied together via a bus bar with a ground wire running outside to a ground rod.
My random wire antenna exits the garage on the same side as the ground rod, but crosses over the back of the garage from the peak of the roof and runs to a tree at the other end of the property.
 
Next bit of advice is one you are just gonna love! That ground rod is a fair start, but only a start with any kind of random/long wire antenna. Adding radials to that ground is the next step. As much as you can get, danged near anywhere you can get it. When you've got as much metal in the ground as you have all the metal in the air, you're about half way done. That's not as much exaggeration as you might think, unfortunately. It WILL make a difference.
- 'Doc
 
Yeah, what 'Doc said is where I was going also. You need a lot more wire in the groudn to make that random wire work correctly. It would also be helpful to have an estimate on how long that wire is to help figure out where it will load up.
 
OK....here's what I originally had that worked very well on both the 40 and 75/80 meter bands.....

Twisted and covered wire stripped out of old #10 gauge fire service extension chord. It exited my tuner on the east side of my garage, was hung insulated from the fascia board around to the back peak of the roof, from there it was suspended to a tree with a PVC pipe insulator, with a pigtail running back down on an angle, again with a PVC pipe insulator and terminated about 3 foot above the top of my wood fence. No ground radials were used, and the grounding rod is located at the front east side of the garage.

When I re-installed this antenna, everything followed the same path, but I removed what was the pigtail portion, and just terminated the slightly shortened version at the tree. This resulted in being able to tune up the 75/80 meter band, but not the 40.

Now I also have a separate ground rod on the west side of the garage as a lightning ground for the Big Stick vertical.
Taking into account of what Doc & Mole suggested, I first tied the two ground rods together with a length of the #10 gauge twisted wire, so now both grounds are tied into each other, then I added two radils to the secondary ground rod since it is virtually right under where the random wire runs. One radil follows the west wall of the garage, and the other much longer one follows the back yard fence along the path of the random wire antenna, past it to the side yard fence.

Now to see if there's any improvement....

:blink:.....DUH.....Yeah....there was......:blink:

Flatter on 75/80, and a dead flat 1.1:1 on 40....

Now there's not much action on 40 meters at the moment, at least nothing I'm picking up with a good clear solid signal, so I really don't know how much of an improvement this will be, and I'm sure from the results two radials and tying both grounds together made, a few more ground radials wouldn't hurt...

My only problem is I have a 20 foot round swimming pool in the way, that and I'm out of wire now.....

Later usually after 5:00 pm there's a group on 3.814.0 Mhz that I'll try and get a signal report from....assuming I can get a word in edge wise with these ratchet jawed rag chewers.......:huh:
 
The kind of wire you use just depends on what you've got. As long as it will conduct electricity it will work. Copper plating your yard is also an option! Dump a 50 pound bag of salt into that pool, that'll work too (also makes you float 'higher' in the water). Know anyone with a machine shop? Metal shavings! Bottle caps? Pull-tabs. Tin can lids.
- 'Doc


Those bottle caps and pull-tabs are secret, don't tell anyone.
 
Well Doc, it was above 80° F in my back yard today, and I only buried about half of the radial, the rest is just laying on top along the fence line.....I lost 10 pounds digging trenches.....

Never did get to test it on 40 meters today...(busy with other stuff)....but I did make a quick 80 meter contact with SR285 on 3.814 Mhz. He had a good signal on me, but he had thunder storms rolling through up his way, and I had a nasty cell passing just to the south of me, so the lightning crashes were seriously interfering with our QSO. I'm going to dig up some more wire, and on the next cooler day bury a few more radials around the pool.....
 
You know, Home Depot has some tools you can rent that will make the digging much easier. Another easier way to do it is to get a very flat shovel...like the kind that landscapers use to cut sod, or roofers use to remove composite shingles. Just place step on it hard straight down to make a nice cut in the ground, wiggle the handle back and forth to widen the cut and stuff the wire down. It's a lot easier than digging.
 
Pretty much what I was doing Mole, but I used a standard flat blade shovel. The problem with following my back fence is my neighbor has ivy that grows through my fence, I had to chop through the ivy, and all the roots in my soil just to get a shallow trench to bury the wire. either way I do it, it's labor intensive.

I'll add more radials over time as I find more scrap wire, and the inspiration hits me to do it.....;)
 

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