Small Backyard; Big Signal -- Shrunken 40 Meter Phased Quads:
By Bob Raynor, N4JTE
Let me state this up front, this is not an antenna project for the faint of heart, nor does it describe an all band, miracle working, coax fed multi DX pile up buster.
It is however a 2 element small footprint 40 meter phased, reversible, downsized quad array that surprised me big time and I am Real picky. So that?s what I am going to describe here with the hope that someone out there will find the same enjoyment I get from this sucker.
I began this project with a lot of unknowns that could only be proven after I built it. This one is way beyond my modeling abilities so real world backyard testing was the only way to go.
How do you shrink 2 full size quads without killing the gain and bandwidth? Is there any way an almost ground mounted diamond shaped quad array will do anything?
Lastly, the big question, could I use a very successful reversible phased vertical Christman, (ON4UN) method of feeding to get that gain and front to back I enjoyed with phased verticals at ? WL spacing.
Well the easy answer is a big Yes and then some. Let me preface everything to follow by stating that this monoband design can be used on any band when extrapolated dimensions are applied. Thanks to Mr. Cebik, sk, I read of a way to capacity load a quad and shrink it in all dimensions by 25% a substantial amount when space is at a premium. He added the extra wire in two horizontal dimensions.

That was my first attempt and it was a nightmare to build with all the floppy wires and anchor strings but it tuned to 7.080, exactly where he predicted, but way too tricky and flimsy to build. My radio was in surgery so I had free time to try a different, hopefully, simpler configuration.
I killed two birds so to speak and attached the capacity load wires to the 40 ft fiberglass center pole and went for vertical polarization by feeding an outside corner to avoid the high current points at the top and bottom corners of the cap wires and possibly screw that up. To be honest it was all guesswork!
Ended up with a much more stable and doable design but would it change anything drastically? Actually no, but for some reason the frequency dropped to 6.9, I did not bother changing anything until the other element was installed, mutual impedance you know!
So I put the second quad up with the exact same dimensions and watched this experiment blow around in 35 mph winds before checking each for resonance.

Long story short, a little pruning got me to 7.150 on both. I hooked up the previous phaselines to the outside corners and checked at the radio. I got a 1.7 swr in each direction, workable with no tuner required.

Front to back was around 4 S units. Usable bandwidth is from 7.135 thru 7.185. The ability to work Corsica and then, with a flick of the switch, contact a Columbia, SA station is a lot of fun especially when both stations report a ?booming?5-9 plus signal report. Rig is IC 735 with AL 811H at 400 watts.
Bottom line is that I am writing this at 3am after spending another fun night working NE and SW DX stations at will on first call. Often I am the first station to place the DX station on the summit and that?s a trip! The quad array is surpassing all expectations and I am very happy with the perceived gain and front to back, subjective I know but this design is gonna be here to the next ?Big Idea?.
What I Learned:
1: The Christman, ON4UN reversible system works great on quads not just ? WL phased verticals.

Expert waterproofing, Not! See for phasing details.
2: A quad correctly shrunk by 25% will do a very credible job on 40 meters if DX is your thing.
3: Vertical polarization on a quad is worth the effort especially at low heights in a diamond configuration.
4: This array outperformed a 40 meter EDZ at 60 ft. the later it got on the band.
5: It is better than a 2 element vertical array previous installed on same poles and much quieter than expected with local QRN.
As I said, this article/project is not for everyone and probably will end up in the ?what?s next? category but if you are trying to work DX in two opposite directions with a signature, consistently strong signal, I guarantee you will be astounded with the results on 40 meters at such a low cost and if modified will work as well on your band of choice!
Tnx for reading,
Bob the Builder