Homemade antenna Issue High SWR

[Handy Andy]

Now, not all is lost, but it will take some "ingenuity" on your part...

Another modified idea if you need more option...

Just make the bottom radial "arm" a METAL conduit - Copper works, but it's ductility is too soft to make it "Stiff" but if you use enough "diameter" of pipe and it's wall thickness is good (Type L or M) you can make this work and make a "sleeve" out of PVC and a wooden broom handle near the bottom to offer a Standoff for this concept to work...

Only difference? The COAX goes INSIDE the conduit down to the mast...past the broom handle "stiffener" support then down the mast...or woven thru a hole into the mast and then continue the downlead...

This is just tentative but allows you to use the hardware and most of the construction "concept" to work just you add in some electrical tape to act as a "gasket" and help support the wood insert to act as a stiffener and isolator support.- a hole can be drilled down and off to one side to allow coax to "exit" - improvise as needed.

​

 

[Gunner357]

O

Ok Ill go out this AM and try that thank you Ill report back

OK I put it back together and in a temp location atm its below roof line and pulled the coax out the best I can for a temp thing and my results ch1 2:1 ch20 2:2 ch40 2:3

 

[Gunner357]

Ya know I appreciate you guys helping me with this.....

 

[Gunner357]

Now, not all is lost, but it will take some "ingenuity" on your part...

Another modified idea if you need more option...

Just make the bottom radial "arm" a METAL conduit - Copper works, but it's ductility is too soft to make it "Stiff" but if you use enough "diameter" of pipe and it's wall thickness is good (Type L or M) you can make this work and make a "sleeve" out of PVC and a wooden broom handle near the bottom to offer a Standoff for this concept to work...

Only difference? The COAX goes INSIDE the conduit down to the mast...past the broom handle "stiffener" support then down the mast...or woven thru a hole into the mast and then continue the downlead...

This is just tentative but allows you to use the hardware and most of the construction "concept" to work just you add in some electrical tape to act as a "gasket" and help support the wood insert to act as a stiffener and isolator support.- a hole can be drilled down and off to one side to allow coax to "exit" - improvise as needed.

View attachment 39395​

So I would solder the coax weave on to the copper pipe correct and make the copper pipe 102 inches with the stinger side also 102 inch but a little longer for tuning

 

[Handy Andy]

Of if you wish, use a "Copper cap" - to cap off the pipe in the sleeve, but use a coupler/joiner/reducer to the 3/4" (straight oversized) and use the SO-239 in that

• - look carefully at the drawings so you can see the SO-239 is installed ON the INSIDE of the cap
  • - with holes drilled thru the cap
• - to push out - raise - the Center Stem of the SO-239 out to the wire going up that upper sleeve.

Use a large hole for that "stem" so it does not short out to the cap

- but the cap "covers" the copper pipe and fits into the coupler
- again you can use simple screws and some electrical tape to form gaskets and to help center the copper pipe in the PCV down side to meet the "dowel" section so the copper pipe has some stiffener in the dowel and support as well to provide spacing and insulation from electrically connecting to and being slightly above that mast pipe.​

 

[Gunner357]

Of if you wish, use a "Copper cap" - to cap off the pipe in the sleeve, but use a coupler/joiner/reducer to the 3/4" (straight oversized) and use the SO-239 in that

• - look carefully at the drawings so you can see the SO-239 is installed ON the INSIDE of the cap
  • - with holes drilled thru the cap
• - to push out - raise - the Center Stem of the SO-239 out to the wire going up that upper sleeve.

Use a large hole for that "stem" so it does not short out to the cap

- but the cap "covers" the copper pipe and fits into the coupler
- again you can use simple screws and some electrical tape to form gaskets and to help center the copper pipe in the PCV down side to meet the "dowel" section so the copper pipe has some stiffener in the dowel and support as well to provide spacing and insulation from electrically connecting to and being slightly above that mast pipe.​

OH I see now Maybe a trip to HD is on the agenda today Im At 2:1 on the SWR now where it sit as shown in the second pic maybe if i put back up it will correct itself I dunno I just dont like heights and Im by myself so its sketchy

 

[nomadradio]

A dipole is a dipole, vertical or not. The coax needs to be perpendicular to the wires. The needed distance is less clear, but the double-bazooka dipole mounted parallel to our tower is six feet away from the tower. The coax is perpendicular to the wires for that distance until it meets the tower leg and goes downhill from there.

Might experiment with the distance to see how much is enough.

73

 

[Gunner357]

Im so done with this Homemade crap Ive been up and down on the house this antenna is so wobbly and the best is 2:1 I added and cut I remeasured I checked for shorts etc etc etc...... Then I gave up laid it on the deck flat and got 1:59 on Ch 1 WTH?? is going on do I just toss it on the ground call it good?? I might just save up and buy a A99 or something....

 

[Gunner357]

sitting on the deck results

 

[bob85]

it looks like you can't install it correctly with the coax at 90 degrees for a good distance so id sack the idea of a conventional vertical dipole,

the way you have it setup the coax is part of the antenna radiating & picking up noise,

it should have a current balun at the feed-point & the coax at 90 degrees to minimise coupling & unbalance,
coax length & where its placed will likely effect vswr & radiation pattern,

looks like you have plenty of spare coax laying on the ground,
as you already have everything you need to make a twig as effective as a99 at same height why not turn your dodgy dipole into a t2lt,

bring the coax straight down the plastic mast & wind a 5 turn choke on 4.25" former 8ft or so down from feed-point, then carry on down to the ground before you run the coax away from the mast,

you don't need the wire inside the mast or the so239 connector, just coax, the mast to support it & some time adjusting the length of top wire & position of choke for best vswr.

 

[Gunner357]

it looks like you can't install it correctly with the coax at 90 degrees for a good distance so id sack the idea of a conventional vertical dipole,

the way you have it setup the coax is part of the antenna radiating & picking up noise,

it should have a current balun at the feed-point & the coax at 90 degrees to minimise coupling & unbalance,
coax length & where its placed will likely effect vswr & radiation pattern,

looks like you have plenty of spare coax laying on the ground,
as you already have everything you need to make a twig as effective as a99 at same height why not turn your dodgy dipole into a t2lt,

bring the coax straight down the plastic mast & wind a 5 turn choke on 4.25" former 8ft or so down from feed-point, then carry on down to the ground before you run the coax away from the mast,

you don't need the wire inside the mast or the so239 connector, just coax, the mast to support it & some time adjusting the length of top wire & position of choke for best vswr.

I I added a Ugly Balun but didnt make any difference i brought the antenna down to where i had it when I was testing it and pulled the coax straight out the best I can the Ungly balun is about a foot off the so239 connector should it be further down the antenna?

 

[bob85]

not if you are making a t2lt, it wants to be about 1/4wave down.

 

[midnight special]

here is an idea

 

[Beetle]

Im so done with this Homemade crap Ive been up and down on the house this antenna is so wobbly and the best is 2:1 I added and cut I remeasured I checked for shorts etc etc etc...... Then I gave up laid it on the deck flat and got 1:59 on Ch 1 WTH?? is going on do I just toss it on the ground call it good?? I might just save up and buy a A99 or something....

You need to use x:1 for your SWR readings. The "R" in SWR stands for Ratio, and ratios normally end with a colon and the numeral 1. "1:59" doesn't even mean anything. In that picture of your readout, that first number, "1.18" represents 1.18:1, and there's NOTHING wrong with that! I think there were five frequencies shown, and all of them were lower than 2:1 (and should be just fine).

 

[Gunner357]

You need to use x:1 for your SWR readings. The "R" in SWR stands for Ratio, and ratios normally end with a colon and the numeral 1. "1:59" doesn't even mean anything. In that picture of your readout, that first number, "1.18" represents 1.18:1, and there's NOTHING wrong with that! I think there were five frequencies shown, and all of them were lower than 2:1 (and should be just fine).

Thanks for the reply The read out 1.18 is from My AA230 zoom when I laid the antenna flat on the deck The 1.59 is also from the meter when I stood the antenna back up......I am aware of the ratio configuration