Random wire question

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jquittum

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Hello,
I currently have random wire connected directly to my IC-7200. I am not transmitting, receive only for now.
It runs out of the house turns 90 degrees and runs approx. 30 feet along a rail of my 6 ft. high privacy fence. It then turns another 90 degrees and runs approx. 60 feet, then turns 90 degrees one more time and runs about 40 feet. Basically a U shape. The rail it sits on is about 9 inches below the top of the fence.
Two questions.
1). Do all the turns affect the receive performance?

2). Would running it through standoffs a little higher than the top of the fence make it work any better.

I can hear some SW, BCB, and Ham as it is. But for the most part, not much more than with the wire I threw up in a tree right outside the window.

Thanks for any thoughts.
 

ridgescan

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If you make that a "system" by getting some 50 or 75 ohm coax as feedline, connecting that wire to the center conductor, then running the braid to earth as the counterpoise, you'd have a nice antenna with cleaner signals. I ran a 100' antenna in an "L" and that bend didn't hurt it.
You could also make a dipole antenna by running coax out to about the halfway point of that "U", cut the "U" to two legs-connect one leg to coax center conductor, connect other end to braid of coax.
 

jquittum

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Might be a dumb question, but; after running the braid to earth, would I join the braid at the radio end to the outside of the connector?
 

nanZor

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I can hear some SW, BCB, and Ham as it is. But for the most part, not much more than with the wire I threw up in a tree right outside the window.

Too much of a good thing down too low. On many frequencies, you have a cloud burner directional pattern, which are heavily attenuated by so much horizontal wire down low.

Think about a simple inverted L, which is operated in non-resonant fashion with a 4:1 or 9:1 UNUN for general purpose SWL receive, and if you do it right, will serve as an amateur antenna as well:

HAM Antenna Resources and Informations: Sep 26, 2013

See the pic about half way down the page which looks like what would work at your location, for SWL or amateur use.

Ignore the inductor and specific wire lengths in the pic, and put something like an LDG 4:1 UNUN (or balun-designs 4:1 UNUN) down near the feedpoint at the bottom of the fence. At the shack, use a 1:1 RF choke, like an MFJ 915, since the coax shield will also serve as a counterpoise and you want to choke that. You could also run counterpoise wires along the bottom of your privacy fence too.

For overall wire lengths, see this chart for amateur use, BUT you can also use the same method for SWL if you want to optimize for SWL bands:

Random Wire Antennas - Best Lengths To Use For Random Wire

Just do a little math for SWL optimization if you like. Or just cut for amateur band lengths, and see if SWL operation is ok. Ordinarily one might try things with the rig tuner, but since you want to do SWL as well, using a 4:1 UNUN at the feedpoint might be the best overall solution. Don't use junk/lossy coax. You might just kill two birds with one stone!
 
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jquittum

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If you make that a "system" by getting some 50 or 75 ohm coax as feedline, connecting that wire to the center conductor, then running the braid to earth as the counterpoise, you'd have a nice antenna with cleaner signals. I ran a 100' antenna in an "L" and that bend didn't hurt it.
You could also make a dipole antenna by running coax out to about the halfway point of that "U", cut the "U" to two legs-connect one leg to coax center conductor, connect other end to braid of coax.
I left the wire as is, but did run some rg8x from the receiver, through the wall, and joined it to the random wire outside of the house. Coax length inside the house is about 20 ft. I grounded the shield to a ground rod outside.
I notice that if I pull the connector out of the receiver so that just the center conductor is making contact, I can't even hear WWV 10.000. But if I then bring the connector back in to make full contact, all the noise goes away and I can hear it perfectly.
So, does that mean things are working like they should? Or is the coax braid just acting as the antenna?
 

jquittum

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I should clarify that I can hear with the just the center conductor, things are just really buried in noise.
 

n3ouc

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Yes, that is the way it is supposed to work.. A fully closed loop like you have with the shield connected to ground and the center conductor to the random wire should remove the noise and bring in a quieter signal such as you have learned. Your on your way to understanding how antenna systems work!!
 

ridgescan

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Yes, that is the way it is supposed to work.. A fully closed loop like you have with the shield connected to ground and the center conductor to the random wire should remove the noise and bring in a quieter signal such as you have learned. Your on your way to understanding how antenna systems work!!
+1. With your center pin only, your coax was coupled to your randomwire, and the whole thing was the antenna.
Once you connected that grounded shield to the radio, it gave the randomwire something to work against and protected signals from the randomwire to radio.
Sounds like you're going to have fun now-especially in your evening/nightfall times when everything comes in better.
Keep us posted!
 

jquittum

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Thanks for all the advice.
I have a Wellbrook loop on the way also. Kind of looking forward to trying it out.
 
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