Base 5/8 vertical above a 5 element beam

[BoxHillBoy]

Have just installed my 45 foot tower I have a 5 element TetEmtron beam and a 5/8 ShockWave vertical. After speaking to the manufacturer of the ShockWave he told me remove the radials (4) and drop the shockwave down close to the beam using the beam as the radials or ground plane. So after doing this the vswr on 26.965 is 1:5:1 and on 27.405 vswr is 2. The only way I can get the vswr down is to put 2x radials on the Shockwave 5/8, I can then get the vswr to 1:3:1 across the range but now this messes up the beam vswr. I have spent days trying so many options, moving the vertical further away, closer and every distance between that with no luck. Increasing and decreasing the coil winding distance from each other. Am I missing something? do I need to radically shorten or lengthen the antenna ? I have tried using the Vswr tune point, no luck.

I have included a pic of the antenna as some will not be familiar with it

Any help will be appreciated

 

[freecell]

are you using the TE-511 beam?

 

[BoxHillBoy]

Yes thats the exact beam

 

[BoxHillBoy]

looking at the pic, the mast sits nearly hard against radiator 1 I think it is, the one that the balun connects to

 

[freecell]

Yes thats the exact beam

that's part of the problem. the entire TE-X11 series of yagi beams are not built using *plumbers delight* construction. the dual fed elements are insulated from the boom leaving the vertical without any elements to collect antenna current at the exact location where they are needed the most, at the feedpoint of the antenna. what you're attempting to do can only be done using beam antennas where *ALL ELEMENTS have a direct conductive electrical connection to the boom.* compounding the matching problems is the close proximity and unwanted mutual coupling of the matching coil at the base of the 5/8 wl radiator to the half-twist matching section connecting the pair of insulated driven elements. for these reasons this combination of antennas will not work well in attempting to utilize the beam as a ground plane for the vertical element.

in addition, the tetemtron line of antennas are grossly overpriced.

if it makes you feel any better this same conversation involving a similar situation was going on in qrz .com 5 years ago and as far as i can tell that was never actually resolved.

 

[BoxHillBoy]

I worked it out late last night, wrapped wire and insulated the beam radials to the boom and bingo, Shockwave dropped to 1:2:1 which could be tuned further im sure but no use.

I went out and go a 1/2 wave station master that does not have radials and in the process of installing that. Hopefully this will cure my problems.

Im only using the vertical to talk local with the mates, if I want some DX time I will switch across to the DX setup.

The shockwave is great antenna so I will probably mount a pole somewhere down the track and recommission it.

Here in Australia the Tet Emtron are not a bad price beam compared to most beams available and I know a few guys who use them and go very very well At this stage I have so much to do around this property it was easier to get a Beam in a box option rather than scratch build something.

Thanks for taking the time to answer my question, I was getting very frustrated after trying so many things. Spent over a day trying many options.

I did a site search and couldnt find a topic that covered my question, I guess I was looking in the wrong topics.