Dipole Questions

[Phil501]

Hey guys, I was reading your comments and thought I'd share my experience I'm going through.....As some of you know, me erecting any kind of Ground plane up in the air is off limits for me right at the time....Hopefully, in the near future I can, but for now, with the CCR restrictions I'm dealing with........Anyways, I have a Flatside 1/2 wave Dipole I constructed with some 14g stranded wire. I am also running a 1<img src=http://www.wwdx.org/smilies/posticon1.gif ALT=":1"> to 1 ProBalun....It is surface mounted on the peak of my roof on my 1 story house running North to South, wich would make it directional East to West....(I Think..LOL)........I too am picking up a lot of static, usually around 2 to 5 S-Units........Especially during the day, when there's alot of electrical activity flying around......Evenings it does simmer down to around 2 to 3 S- Units. But it's real annoying for sure..........I don't have any power lines or nothing close by, just vents and what not, on a normal roof......I was wondering if I were to elevate it somewhat so it's not surface mounted right to the composition shingles if it would cut down on the white noise., Remember, though I can't really put it in the air alot, I still want to run in STEALTH mode...........Any input would be great......73's all.....

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[Moleculo]

Dipoles close to the ground can be noisy antennas. Get it up on the air and away from the power lines if you can. Also, what configuration is your dipole? I'm guessing from your comments about the polarity that it's a flat, horizontal dipole? With any dipole that's a lot less than 1/2 wavelength high, most of you signal is going straight up.


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[Phil501]

Hey Mole, the dipole is up about 20 feet or so above ground, but being surface mounted to the shingles, I think this might have something to do with it.......I got my wire measurements for this link www.hamuniverse.com/dipivcal.html



I've made two dipoles...... one with Balun and one without......Both have great matches with just the precise measurment given......I don't want to cause another oppinion war with Baluns to No Baluns.......LOL........ When I first keyed up and checked SWR's they both had a 1:3 to 1 match.....I'll live with that.......I was wondering if I elevate it off of shingles if this will help with noise........Also my RF with my house is off the hook.........I had to damn near choke everything in the house...... TVs, VCR's, Phone anything with a speaker......LOL.......I do have a 8' grounding rod less than a 1/4 wave (102 inches) with good braided wire going right to the wing nut on the back of my Kenwood......I'm only pumpin' about 150 whiskeys.......With speach processor on (350w)........It's real bad.........Good luck Bob.......I'm in the same boat as you bud..........Waiting for fishing season my self........73's

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[Sonwatcher]

Bob,

You gave me the bug !<img src=http://www.wwdx.org/smilies/yelclap.gif ALT=":yelclap"> I made a dipole for 11 meters. 8.6 ft. per side. I hooked up the coax and checked my swr's and they are pretty well flat.Now I can't wait for some DX to give 'er a try !<img src=http://www.wwdx.org/smilies/posticon51.gif ALT=":51">

</p>Edited by: <A HREF=http://p067.ezboard.com/bworldwidecbradioclub.showUserPublicProfile?gid=sonwatcher>Sonwatcher</A> at: 3/5/05 4:46 pm

 

[Sonwatcher]

Bob, I have it up about 20 ft. from ground level. I don't notice a bad amount of noise. But I did talk to CDX-4540. He said he hears me normal but I did notice on my end his signal was down. I guess this would factor into that he is on a vertical antenna.



( trout getting ready to open here soon ! My son caught a Brown around 25 inches. He beat my 21-1/2". So I gotta go for the big one !<img src=http://www.wwdx.org/smilies/posticon23.gif ALT=":23"> <img src=http://www.wwdx.org/smilies/posticon25.gif ALT=":25"> )



I forgot, It is horizontal

</p>Edited by: <A HREF=http://p067.ezboard.com/bworldwidecbradioclub.showUserPublicProfile?gid=sonwatcher>Sonwatcher</A> at: 3/5/05 5:13 pm

 

[Sonwatcher]

Bob,

4540 lives about 10 miles from me. I did notice after he and I went to both vertical he said my audio went way up. So I guess I'll just have to wait for some DX to check out the homebrew<img src=http://www.wwdx.org/smilies/icon95.gif ALT=":jumpy">



I checked 555 usb but didn't hear anyone.

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[Sonwatcher]

I have a question. Would a coax balun help with the noise factor on a Dipole ?

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[Moleculo]

No, that won't help with noise. That will help with RFI in the house. The point of the balun is to get rid of common mode current....that's RF that's on the shield of the coax. It won't affect your SWR either. I find that I get RF in the house coming in on the power lines. Some good RF attenuating power strips usually does the trick.


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[Sonwatcher]

Thanks Eddie !<img src=http://www.ezboard.com/intl/aenglish/images/emoticons/wink.gif ALT="">

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[Lazybones1222]

Really? Interesting. Flat on the roof or does it need supported up off the roof?



Oh yeah - about what freq is it resonant at and how do you tune it?

</p>Edited by: <A HREF=http://p067.ezboard.com/bworldwidecbradioclub.showUserPublicProfile?gid=lazybones1222>Lazybones1222</A> at: 3/10/05 6:39 pm

 

[Sonwatcher]

Thanks RfMatrix ! Looks like I have a new prodject to undertake<img src=http://www.wwdx.org/smilies/posticon27.gif ALT=":27">

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[Moleculo]

<blockquote>Quote:<hr>Flat on the roof or does it need supported up off the roof?<hr></blockquote>



You can do it flat or can do it vertical. Each way will have a different radiation pattern. When I get a few more minutes to post, I'll be happy to put up some more details of this antenna if there's interest or if someone doesn't beat me to it...


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[Sonwatcher]

I tried my dipole as an inverted V but the noise level was high and receive very low.

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[Sonwatcher]

Bob701,

I was doing some research on the dipole. I found many said to use a ground wire to take away the bad noise level.I use an antenna tuner with a ground connector. I grounded all my equipment this morning and ran the ground wire to the antenna tuner where the dipole is connected by a coax connecter.All my noise that I had is gone. My receive is way up and CDX-4540 said the Tx volume on my dipole is about equal to my groundplane.<img src=http://www.wwdx.org/smilies/posticon51.gif ALT=":51"> <img src=http://www.wwdx.org/smilies/icon95.gif ALT=":jumpy">

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[Sonwatcher]

Yepper Bob. It's horizontal. Mexico bout blew me out of the water.<img src=http://www.wwdx.org/smilies/rollingaround.gif ALT=":rollingaround"> I'm very pleased. I'm VERY happy I did the research. Noise level is null now.<img src=http://www.wwdx.org/smilies/posticon25.gif ALT=":25">

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