Dipole 1/2 Wave Base Antenna

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ironman1956
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Dipole 1/2 Wave Base Antenna

#362585

Post by ironman1956 »

I have ordered my ssb/am Uniden and a power supply along with an antenna. The antenna is a dipole 1/2 wave which is 17 feet 2.4" long . I am going to give this a try when things arrive to see if it will possibly work for shooting skip and just enjoying the airwaves. Any comments on or suggestions on how to position the antenna would be appreciated or links to videos on how to get the most out of it.
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#362593

Post by wi 544 »

if you have some coax this is one fo the easiest antenna's to make,,

end fed 1/2 wave vertical dipole:
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-357Mag

#362604

Post by -357Mag »

I Built my Dipoles they are cheap simple and effective. If you run it in the Horizontal plane it is a great DX antenna but not so good for local. It will need to be at least 8' (1/4 wavelength) in the air to get a good radiation pattern. It can also be ran in an Inverted "V" Pattern as long as the + &- are kept at least at a 45 deg angle to the feed point moving them to close together will cause the SWR's to change also the feed point needs to be at least 18' off the ground( 1/2 wave length) the tips need to be 8' off the ground. Running in a Inverted "V" changes it's radiation pattern to more of an omni directional pattern so it is still good for DX and better for local.
Since Dipoles are a "Balanced line" when you tune a Dipole you need to be really accurate in you measurements of the radials in what you do on one side you must do to the other equally. If you need to shorten it SWR's High on the bottom end of the band as an example say 3" if you shorten the + side 3" then the - side must be shortened the same amount. I don't recommend cutting the radials but fold then back on each other and secure with zip ties until you achieve your lowest SWR. Say you get it to 1.7:1 on ch 1, 1.3:1 on ch 20 and 1.5:1 on ch 40 by shortening the radials, you can further affect the SWRs and possibly drop them more by moving the radials either father or closer in the inverted "V" configuration, remember you need to move both ends equally. Enjoy your new Rig see you on the air 73's
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#362607

Post by ironman1956 »

Thankyou 357 for the info. I am mainly interested in long distance contacts and enjoying the airwaves in my retirement since I am disabled. I appreciate all of the good info you have given me. My best friend and classmate from our high school years still has his penetrator 500 by Hi Gain in the shed. It is a 5/8 wave and when I lived in West Texas we both had the same antennas and had similar setups, with him a Realistic Navaho and me a President Washington. I am excited about getting back into the hobby. I live in a two story house (my own) and can place the dipole along the eaves which are very high and start out with that. You guys on the forums are of such great help . My Uniden Bearcat should be here Tuesday along with a 12 amp power supply from Pyramid and the dipole which is U.S. made should be here shortly after that. Hope to get on the air soon.

-- Friday, 12 September 2014, 16:30 PM --

I picked up an SWR meter at radio shack with a 2 foot jumper. I know it is important to know what is going on.
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Deleted User 14541

#362610

Post by Deleted User 14541 »

wi 544 wrote:if you have some coax this is one fo the easiest antenna's to make,,

end fed 1/2 wave vertical dipole:
Nice! A mini gain master.
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#362614

Post by halfwatt959 »

Congatulations on getting back into the hobby and welcome to the show. Best of luck to ya and maybe I'll catch ya on the air. My dx # is 2 and 3/4. also known as halfwatt radio. 73s Karl
2 and 3/4 DX RADIO CHAOS. Halfwatt959 " I MAY NOT CAN FIX IT BUT I CAN TAKE IT APART"
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#362620

Post by ironman1956 »

halfwatt959 wrote:Congatulations on getting back into the hobby and welcome to the show. Best of luck to ya and maybe I'll catch ya on the air. My dx # is 2 and 3/4. also known as halfwatt radio. 73s Karl
Okay got it.
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#362623

Post by MDYoungblood »

I like wi 544 illustration, you could installed it in some PVC and make it self supporting, it is the basic design of most fiberglass antennas today.

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#362630

Post by ironman1956 »

wi 544 wrote:if you have some coax this is one fo the easiest antenna's to make,,

end fed 1/2 wave vertical dipole:
Not sure but it says I do not have permission to view the files attached, can someone clarify this for me. Thankyou and just counting the days down to get back on the air. Have been off since 1988. Retired now and gee should have done it sooner. Thanks to everyone for being so helpful, that is the one thing I remember about the cb talkers everyone is always there to help or offer advice , a friendly bunch of people.
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#362631

Post by MDYoungblood »

ironman1956 wrote:Not sure but it says I do not have permission to view the files attached, can someone clarify this for me.

Your post count isn't high enough to do so, privileges come in time and posts, keep up the good work and your be there in no time.

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#362633

Post by Bluerunner »

That illustration is of a RFD (reasonant feedline dipole) antenna I made a while back. It works pretty good.

You can put it in / on PVC pipe, but you may want to use something like 2" or better so it doesn't bow over in the sun.

I hang it about 60' up in a pine tree on a rope. For a self supporting one I'd use a fiberglass / bamboo fishing pole for the top section and maybe 10' length of 2 to 2 1/2 " PVC for the bottom. A light fishing pole may prevent the lower PVC section from bowing some. You probably want to keep any metal pole about 12" below and away from the coax choke coil. Further enlightenment has proven that 5 turns of coax close wound on the 4" PVC form to be best.

Tuning is done by lengthening or shortening the top wire (just folding it back on itself and wrapping it, no need to cut it) and sliding the choke coil up & down a bit.

The actual dimensions will vary some from the illustration, depending on your particular installation and height above earth, but will probably be a good starting point.

Still smoking. I quit several times a day.
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#362977

Post by ironman1956 »

-357Mag wrote:I Built my Dipoles they are cheap simple and effective. If you run it in the Horizontal plane it is a great DX antenna but not so good for local. It will need to be at least 8' (1/4 wavelength) in the air to get a good radiation pattern. It can also be ran in an Inverted "V" Pattern as long as the + &- are kept at least at a 45 deg angle to the feed point moving them to close together will cause the SWR's to change also the feed point needs to be at least 18' off the ground( 1/2 wave length) the tips need to be 8' off the ground. Running in a Inverted "V" changes it's radiation pattern to more of an omni directional pattern so it is still good for DX and better for local.
Since Dipoles are a "Balanced line" when you tune a Dipole you need to be really accurate in you measurements of the radials in what you do on one side you must do to the other equally. If you need to shorten it SWR's High on the bottom end of the band as an example say 3" if you shorten the + side 3" then the - side must be shortened the same amount. I don't recommend cutting the radials but fold then back on each other and secure with zip ties until you achieve your lowest SWR. Say you get it to 1.7:1 on ch 1, 1.3:1 on ch 20 and 1.5:1 on ch 40 by shortening the radials, you can further affect the SWRs and possibly drop them more by moving the radials either father or closer in the inverted "V" configuration, remember you need to move both ends equally. Enjoy your new Rig see you on the air 73's
I did get my dipole installed at 20 feet in the air. The raidals are at about 50 degrees off of the center line pointing downward. I used electrical grey pvc and purchased a 45degree fitting and used the 1/2 inch grey pipe to do this. Then I fastened the wire to the pipe with black tape. The 108 inch wires on the dipole came within a foot of the 1/2 inch tubings so I drilled a hole in them and used fishing spider wire to stabilize the dipole legs hanging down. SWR was at the highest 1.3 and 1.1 on other channels. I am just playing right now and have a Sirio 27 5/8 wave ground plane with long radials ordered and it comes in tomorrow on the 24th of Sept. Thanks for all the good tech info.

-- Tuesday, 23 September 2014, 6:36 AM --
-357Mag wrote:I Built my Dipoles they are cheap simple and effective. If you run it in the Horizontal plane it is a great DX antenna but not so good for local. It will need to be at least 8' (1/4 wavelength) in the air to get a good radiation pattern. It can also be ran in an Inverted "V" Pattern as long as the + &- are kept at least at a 45 deg angle to the feed point moving them to close together will cause the SWR's to change also the feed point needs to be at least 18' off the ground( 1/2 wave length) the tips need to be 8' off the ground. Running in a Inverted "V" changes it's radiation pattern to more of an omni directional pattern so it is still good for DX and better for local.
Since Dipoles are a "Balanced line" when you tune a Dipole you need to be really accurate in you measurements of the radials in what you do on one side you must do to the other equally. If you need to shorten it SWR's High on the bottom end of the band as an example say 3" if you shorten the + side 3" then the - side must be shortened the same amount. I don't recommend cutting the radials but fold then back on each other and secure with zip ties until you achieve your lowest SWR. Say you get it to 1.7:1 on ch 1, 1.3:1 on ch 20 and 1.5:1 on ch 40 by shortening the radials, you can further affect the SWRs and possibly drop them more by moving the radials either father or closer in the inverted "V" configuration, remember you need to move both ends equally. Enjoy your new Rig see you on the air 73's
I did get my dipole installed at 20 feet in the air. The raidals are at about 50 degrees off of the center line pointing downward. I used electrical grey pvc and purchased a 45degree fitting and used the 1/2 inch grey pipe to do this. Then I fastened the wire to the pipe with black tape. The 108 inch wires on the dipole came within a foot of the 1/2 inch tubings so I drilled a hole in them and used fishing spider wire to stabilize the dipole legs hanging down. SWR was at the highest 1.3 and 1.1 on other channels. I am just playing right now and have a Sirio 27 5/8 wave ground plane with long radials ordered and it comes in tomorrow on the 24th of Sept. Thanks for all the good tech info.
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#362995

Post by Lost Ram »

Glad to see folks getting back on the air. Its even better to see people still doing DIY antenna's and such.
Its not as busy as it was back in 1988 but there are still plenty of folks around and great skip lately.
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