Huh? What's the DiBar and Quad Disk?

I'm about to put a 102" on a ball mount for HF.

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the Francis DiBar supports 2 CB50 Amazers for increased gain over a single CB50. the Quad Disk supports 4 CB50's for the most powerful, broadbanded mobile antenna ever built for 11M. see the First Picture link on the page linked to above. the TriQuad Mobile Array covers 21 - 33 Mhz. and never sees anything higher that a 1.5:1 SWR across the entire range.

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292 Radio Shop / FireCommunications Network
The Technicians Exchange    ASH    Ref

OK, I've seen 102's used in pairs to gain bandwidth on a single bar. It also increases gain?

How would this Quad be mounted?

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"OK, I've seen 102's used in pairs to gain bandwidth on a single bar. It also increases gain?" How would this Quad be mounted?

multiple radiators fed in phase produce pattern compression in the elevation plane which results in increased gain at more advantageous take-off angles. the CB50 achieves greater broadband capability due to the fact that the three 1/4 wave elements are cut below, at and above resonance with respect to the 11m band. like other "large" antennas, a heavy duty mount is recommended, especially when using 4XCB50's on the Quad Disk.

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292 Radio Shop / FireCommunications Network
The Technicians Exchange    ASH    Ref

A 'thicker' antenna can increase bandwidth. Does nothing for gain.
- 'Doc

the only thing "thick" here is you.

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292 Radio Shop / FireCommunications Network
The Technicians Exchange    ASH    Ref

freecell,
Then here is your chance to enlighten this 'thick' person. How does increasing the apparent diameter of a conductor contribute to increasing gain of an antenna system?
The apparent, or effective diameter of an element, it's thickness, can and certainly does have an effect on the required length of that element for resonance. It can, to some limited degree, effect the usable 'bandwidth' of that radiating element. That's been a 'known' for quite some time, eg: 'fat' antennas, 'cage' antennas. Depending on it's limitations, an antenna modeling program (Nec2) will show this 'bandwidth' characteristic quite clearly. None of that increases that antenna's gain by any practical or realistic degree. That's from the theoretical stand point of modeling programs, and from practical experience (and not just my experience, by the way).
So show me. I am waiting eagerly for enlightenment.
- 'Doc

"How does increasing the apparent diameter of a conductor contribute to increasing gain of an antenna system?"

no one said that it did.

multiple radiators fed in phase produce pattern compression in the elevation plane which results in increased gain at more advantageous take-off angles.

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292 Radio Shop / FireCommunications Network
The Technicians Exchange    ASH    Ref

So it works in some similar way to the way an omnidirectional 4-element collinear array for 2 meters works, to produce gain towards the horizon over , say, that of a single quarterwave element antenna?

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Highlander, NA-821 on 11 Meters.
N9RZF, David on Ham Bands.

Yaesu FT-847, Galaxy DX-2517, President Lincoln, Cobra 150 GTL, Uniden Grant LT.

same principle. a single end fed full size quarter wave radiates a high amount of energy skyward or at high angles in the elevation plane. the downward compression of this energy results in eliminating radiation wasted at higher less advantageous angles.

as in the 2 meter example that you used, this downward compression results from the stacking of additional elements in the vertical plane. in the TriQuad, this same compression is achieved using a plurality of elements (12) fed in phase in close proximity to one another with initial antenna currents in elements tuned at, below and above resonance reinforcing those electric fields at lower angles, eliminating wasted skyward radiated energy. the ability of an antenna to eliminate radiation in undesired directions and focus it into the direction desired is the definition of antenna gain.

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292 Radio Shop / FireCommunications Network
The Technicians Exchange    ASH    Ref