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ID an antenna..?

 

Hi;
?
Does anyone recognize this antenna? It's part of a 4-bay UHF folded dipole array I got from a friend, who in turn bought it (he thinks ebay..?) probably a decade ago or more. It doesn't resemble the homemade offerings from the current Ukraine or Indonesian vendors-- they're constructed from tubing and this is flat stock; about 1cm x 2mm. The black plastic box *could be* 3D-printed but I see circular scratches, rather than straight lines. Obviously nothing like Telewave or DB Products.
I'm looking for spacing/pattern info, in the end but also curious as to its origin.
?
Cheers,
Bob
KK6RQ
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?
?
 

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Not much help, but I vaguely remember an antenna like this from years ago. No idea from where or whom made it (including the possibility that it was a construction project.)

Chuck
WB2EDV



On 2/20/2025 1:47 AM, Bob KK6RQ via groups.io wrote:

Hi;
?
Does anyone recognize this antenna? It's part of a 4-bay UHF folded dipole array I got from a friend, who in turn bought it (he thinks ebay..?) probably a decade ago or more. It doesn't resemble the homemade offerings from the current Ukraine or Indonesian vendors-- they're constructed from tubing and this is flat stock; about 1cm x 2mm. The black plastic box *could be* 3D-printed but I see circular scratches, rather than straight lines. Obviously nothing like Telewave or DB Products.
I'm looking for spacing/pattern info, in the end but also curious as to its origin.
?
Cheers,
Bob
KK6RQ
?
?
?
 

So it looks like nobody conclusively recognizes this array;? Can anybody offer any generic advice with regard to element spacing when it comes to an unknown 4-bay dipole array? The horizontal mast-element spacing is fixed; all I've got to work with is the vertical inter-element spacing.
?
ps.? There's nothing on the phasing harness to ID what kind of coax it is, either.
 

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According to the ARRL handbook graph, the most gain is at 0.45 wavelength of space between element tips. See picture. Also the top of the mast needs to be at least something like almost 1/4 wavelength above the top tip of the highest element.?
?
John

On 03/08/2025 10:53 PM EST Bob KK6RQ via groups.io <nuhtrue@...> wrote:
?
?
So it looks like nobody conclusively recognizes this array;? Can anybody offer any generic advice with regard to element spacing when it comes to an unknown 4-bay dipole array? The horizontal mast-element spacing is fixed; all I've got to work with is the vertical inter-element spacing.
?
ps.? There's nothing on the phasing harness to ID what kind of coax it is, either.

DSC01282.JPG

 

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From the engineering section of an old Decibel catalog:

For optimum gain and performance, the centers of the antennas (radiator center) should be physically separated a given distance. This distance is not too critical but should be held to within 10%. For most vertically stacked arrays optimum spacing will occur around 0.85 to 0.95 wavelength as measured between centers.

Chuck
WB2EDV



On 3/8/2025 10:53 PM, Bob KK6RQ via groups.io wrote:

So it looks like nobody conclusively recognizes this array;? Can anybody offer any generic advice with regard to element spacing when it comes to an unknown 4-bay dipole array? The horizontal mast-element spacing is fixed; all I've got to work with is the vertical inter-element spacing.
?
ps.? There's nothing on the phasing harness to ID what kind of coax it is, either.
 

Yes Chuck, that is a better measurement, because the ARRL dipoles in their testing were probably? not the shortened fatter folded dipoles currently made commercially, which would increase the ideal space length to perhaps 0.5 wavelength end-to end.
The ARRL graph does show that it is better to err on the long side, but in practice the coax harness may be the limiting factor.
?
John

On 03/09/2025 9:42 AM EDT Chuck Kelsey via groups.io <wb2edv@...> wrote:
?
?
From the engineering section of an old Decibel catalog:

For optimum gain and performance, the centers of the antennas (radiator center) should be physically separated a given distance. This distance is not too critical but should be held to within 10%. For most vertically stacked arrays optimum spacing will occur around 0.85 to 0.95 wavelength as measured between centers.

Chuck
WB2EDV
On 3/8/2025 10:53 PM, Bob KK6RQ via groups.io wrote:
So it looks like nobody conclusively recognizes this array;? Can anybody offer any generic advice with regard to element spacing when it comes to an unknown 4-bay dipole array? The horizontal mast-element spacing is fixed; all I've got to work with is the vertical inter-element spacing.
?
ps.? There's nothing on the phasing harness to ID what kind of coax it is, either.

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