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Thread: Homemade quarter-wave ground plane base antenna

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    Homemade quarter-wave ground plane base antenna

    1.3:1 across all 40 channels. Any Pointers? Its my first build. Any advice would be great. Its about 30Ft in the air
    Click image for larger version. 

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    Happy DXing

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    Pic is not showing up Matt. Can you post another?

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    Never mind it showed up.

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    Man if you don't have bad weather conditions and wind, a Sirio vector 4000 would work well for you! Mount it about 25-30ft off the ground right where that antenna is now and you will have one nice vertical antenna.
    If the one you have up now works, then by all means use it! But be weary of running any power through it just in case. JMHO.

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    Also a 1:1 matching balun may help you. This will match the impedance if there is any mismatch as your radio wants to not only see a good or decent VSWR reading, but also wants to see the correct impedance, which is 50ohms or near that. 48-52 ohms is a good area. Just some food for thought. The antenna looks good and should work well. Just don't want to see you mess up any of your radios due to impedance mismatch is all. A 1:1 matching balun will help, or slant your radials down more toward a 45 degree angle to the center radial. Again, not trying to tell you what to do, just trying to help is all. I truly hope that the antenna works well. Also you may want to look into building a dipole and hanging it between 2 trees if possible. Get it up to 30ft or more and it will rock!!! But your antenna looks good and should work well for local and DX as well. It's fun building antennas, but you need an antenna analyzer to tune them correctly. Something like an MFJ 269C or similar. Keep at it. And have fun. That is what it's all about!! And. E safe as well!!! Have a good day!!

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    Hello M1989: That 1/4 WL GP Antenna can be adjusted pretty close to a 1 to 1.0 SWR if you wanted. Buy adjusting the vertical radiator and ground plane radials lengths. But 1 to 1.3 coming out of the gates the first time it pretty good!

    Using a antenna analyzer to sweep the frequencies will show were the lowest SWR is allowing you to adjust the antennas lengths to were you want it to have the lowest SWR. If the lowest SWR is below CH 1 then its too long, if its above CH 40 then its too short. Somein like that.


    The 1 to 1 Balun will not match any impedances, but choke off unwanted coax radiation, but usually not needed on gp antennas. Good going its looking good, and will work well nosing ahead of the non ground plane fiber glass antennas. Hope its not to close the tree's.

    Jay in the Great Mojave Desert

  7. The Following User Says Thank You to Jay Mojave For This Useful Post:

    BOOTY MONSTER (09-25-2016)

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    Sorry about the post. Jay is correct you have the antenna setup right. No need for a balun unless it's for CMC issues. I see how the radials are now. Took me a bit. Been a long day. Been up with my father since 2am. He has Alzheimer's disease. Like I said, It's been a long day for me!! The antenna looks good Matt and like Jay Mojave stated, a little trimming and you most likely could get a pretty flat or near flat VSWR. Not that a 1.3:1 is shabby by any means! You should be fine with that antenna and the height that it's at!! Have fun with it! And happy DX'ing, what little there is!! Catch it while you can. Been getting a lot of island activity here. Ol Witch Doctor and a few others in the islands have been coming into FL. Some Cali and up north stuff occasionally as well. I have just been sand bagging myself. The locals are back out again here which is a good thing as well. Hopefully you have some locals near you as well. Makes for good times when the DX is dead!! Anyways. The antenna looks good and should work well. Like I said, have fun with it!!! And have a good day. Also thx Jay for making me look again at the antenna, as I was out of it most of the day. I see now what I missed!! Hope all is well your way.
    222 Daytona Beach, FL
    saying 73 and God Bless.

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    used a PVC X for the standoffs on my 1/4 wave and my first 5/8 wave antenna ...... simple and very effective . nice looking homebrew you got there .

  10. The Following 2 Users Say Thank You to BOOTY MONSTER For This Useful Post:

    222DBFL (09-26-2016), Double Six (05-25-2017)

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    How's it going BOOTY MONSTER. Been a while since I have seen you around or even spoken with you. Hope all is well and thx for responding. You know way way more than I do about antennas!!! That I know is a fact!!
    I am using the Sirio vector 4000 with a couple of simple mods I did to it and it has held up through a pretty rough summer here around central FL. It's one heck of a vertical antenna. But that is JMO. I know many say they are weak. And I would have to agree, they could use some modding in specific places to strengthen them up. But other than that they are a great vertical antenna IMO. What's your take on them?? Just curious.

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    Hello All: Gee whiz I left some stuff out there, probably too early with out coffee.....

    The Balun doesn't usually need to be on ground plane antenna, but there are designs that may need a Balun, but I have not done a lot of testing on this. I have seen beam antennas work well without a Balun with direct feed. Then using a different length of coax on the same beam antenna NOT work at all, and had to install the 1 to 1 Balun. What I suspect is different lengths of coax may cause this. But need more testing. But its always a good call to use a Balun for the direct feed beam and dipole antennas.

    Hope the best for your family.

    I have reinforced the Sigma 4 antennas with internal tubing, especially at the base of the antenna were all the stress is, yeah it was slightly heaver but way more stronger. Also replaced the bottom 1 1/2 inch diameter tubing with Aluminum Pipe with a .120 inch wall thickness, and other internal reinforcements. And it survived the strong and constant Santa Ana winds over the years we have here in the Mojave Desert.

    Jay in the Great Mojave Desert

  13. The Following User Says Thank You to Jay Mojave For This Useful Post:

    222DBFL (09-26-2016)

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