Homemade antenna Issue High SWR

[Gunner357]

I made this "SIMPLE ANTENNA" Set it up in a temporary place Match it got it to 1:2 on ch1 and 1:3 on 40 so I then went bought 60 feet of RG213 raised the antenna up 40 at the tip on antenna now I have 4.5 on 1 and 5.1 on 40 using a RigExpert AA-230 zoom analyzer.... I checked for shorts in coax all is good......Please help

 

[sp5it]

Where are the radials?

 

[ForestRunner98]

I am far from an expert but shouldn’t it have a ground plain?

 

[Gunner357]

This antenna plan didn't require them .... The stinger goes up The GP goes down same length on both trim both when matching to sp5 its question to forestrunner the gp goes down inside mast

 

[sp5it]

Show that plan.

 

[Gunner357]

Show that plan.

https://www.instructables.com/id/Simple-CB-base-station-antenna/

 

[Gunner357]

https://www.instructables.com/id/Simple-CB-base-station-antenna/

same but a little different on this you tube video

 

[Gunner357]

I just dropped it off the roof put it back where i WAS getting 1:2 and it at 6.5 now only other thing that is different is the rg213 i have on it now from the rg8x I had on it while matching earlier... the coax has no shorts I tested with my Fluke meter

 

[nomadradio]

And how well are the connectors installed on the RG213? Is the shield braid soldered to the body of the plug on both ends?

73

 

[HomerBB]

Not sure I followed those instructions, but it seems to me you built a dipole fed in the center.
The coax feedline going straight down the PVC pipe in which the lower dipole leg is contained is a recipe for rf coupling, a bad match and skewed rf pattern. The instructions say use a certain length mast (I think). Probably this length masks the bad design by earth coupling. When you raise the antenna up higher the SWR goes awry.
All I said is based on my assumption it's a vertical dipole you built.

 

[Gunner357]

I checked the cable with the AA230 zoom Cable loss 0.60DB @27405 MHZ 49.8 ohms

And how well are the connectors installed on the RG213? Is the shield braid soldered to the body of the plug on both ends?

73

yes all soldered and verified

 

[Gunner357]

Not sure I followed those instructions, but it seems to me you built a dipole fed in the center.
The coax feedline going straight down the PVC pipe in which the lower dipole leg is contained is a recipe for rf coupling, a bad match and skewed rf pattern. The instructions say use a certain length mast (I think). Probably this length masks the bad design by earth coupling. When you raise the antenna up higher the SWR goes awry.
All I said is based on my assumption it's a vertical dipole you built.

correct i dropped the antenna back down to ground level where it did get 1:2 but now with the RG 213 on its gone crazy and I did check the coax with my AA-230 Zoom analyzer ans all checks out ok.....cable loss 0.60DB @27405 MHZ 49.8 ohms

 

[Handy Andy]

I concur with Homer - The Coax being so close to the mast / dipoles' other half - generates the reflection - proximity.

It see the "construction and assembly" - like this - the site unless you're a member doesn't seem to offer photos of the work unless they took them down...so All I can do is imagine this...

​

 

[HomerBB]

Do not run the coax down by the PVC. Run it straight out away from the dipole for several feet. Nine or more feet is prefered, but at least 4' away before letting it run parallel to the dipole has worked for me.

 

[Gunner357]

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Do not run the coax down by the PVC. Run it straight out away from the dipole for several feet. Nine or more feet is prefered, but at least 4' away before letting it run parallel to the dipole has worked for me.

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