Quad with a ground plane above.

[EDUK8TR]

I have seen pics of a Yagi type beam with a vertical ground plane mounted above it. ie Jay's Crusader beam with an I10k above it. Anybody done the same with a Quad beam say 4 elements and a vertical ground plane? If so, how much higher would the vertical need to be above the quad? Or is the Quad too sensitive for such a configuration. I've been reading alittle about quad beams but haven't run across this particular subject in my research.

Thanks!

Wayne C.

 

[jonbah]

That's a good question, I would think you would get interaction between the two antennas, but a quad? not sure about that. This should be an interesting post.





Jonbah

 

[Marconi]

Wayne I'm thinking the if the quad is current fed and is horizontal, feeding at a 6:00 o'clock current node, then you will have another current node at the 12:00 o'clock point on the quad wire, so having another element there nearby and above this quad element will be of little consequences.

If you are feeding the quad in the vertical at 3:00 or 9:00, then you will have a voltage node at 12:00 o'clock, and maybe then the presence of another vertical antenna will be a problem.

It will be the exact opposite of course feeding a quad like the Signal Engineering antenna because it is voltage fed, because here the quad wire loop is continuous. Everything here is the exact opposite from the traditional quad element that is fed at a current node with an insulated (split) feed point.

At any case all such installations bear close observation for ill affects. In my personal experience with ground plane type antennas above horizontal yagi antennas, I find no noticeable problems.

 

[EDUK8TR]

Thanks Marconi!

I have looked at the Signal Engineering quads and find it interesting the dual polarity set up they employ. I don't have the ability to even setup a beam where I live, but one can dream I guess. I was thinking of a setup that would use a 4 element Signal Engineering quad with a I10K with the ground plane radials about 20 ft above the quad. Would that work :?:

BTW, the "dream" came about recently when I was out looking at some property to build on. As some of you know I live in the Mtn.s of VA. This property is located on top of a ridge that has a wonderful unobstructed 360 degree view of the surroundings. Excellent spot for radio ops.

73's

 

[smokercraft]

quad

I have a friend that runs a old pdl and he has a Imax about 15 feet on top of that.Does not seem to affect either one.Unless you are ready to shell out quite abit more money to ugrade the hardware on the s/e quad I would wait on jay's.I have built four of the s//e quads, they are talkers but the hardware that tony sends with them won't last six months if you have any kind of wind or bad weather.I believe marconi may have seen these, he may be able to shed a little more light.

 

[RoadWarrior]

I had a S.E. Quad. VERY POOR CONSTRUCTION QUALITY!

 

[EDUK8TR]

I wondered about their durability. As stated I'm not in the market right now, but it is good info to know. Jay is working on a Quad? Hadn't heard that

 

[W5LZ]

EDUK8TR,
A quad isn't any more 'sensitive' than other kinds of beams, and another antenna close to it won't degrade it to any greater extent than it would a yagi. The best seperation between antennas for the same band are as much as humanly possible. When you translate that into 'practical' terms, it means as much as you can get without major construction. Lots of help, right? Oh well.
- 'Doc