Hbvc9 antenna

[nfsus]

I've finished building and tuning my first goofy beam. Whoever though of these was smoking crack. It tuned great. Rejection from 30db to 5db on my neighbors signal about 3 miles away. Its horz right now 6ft off the ground. I'm waiting to get a radio check later from a further local station with a horz later tonight.

I fed the "front" short side and then jumped it over to the "back" longer side. The tuning went easy enough but the front element adjustment seems to be the only real adjustment. The back does affect it but not like the front. The gamma match went super well.

I'm using left over ground radials from an old groundplane for the elements. I'll post pics of the build after I clean it up. Right now it's in the ugly wirenut and tape phase. I've posted a pic of the match. 6ft off the ground and horizontal. No capacitor or inductors. Only the twin gamma match.

 

[sp5it]

Never heard about Hbvc9 antenna.

 

[nfsus]

I never had either untill a week or so ago. Its supposed to be a huge thing overseas but nothing here. Very neat possibilities for gain.

Never heard about Hbvc9 antenna.

 

[freecell]

HB9CV: https://www.dxzone.com/catalog/Antennas/HB9CV/

The HB9CV-Beam is a 2-Element-Yagi with two driven elements and was introduced by Rudolf Baumgartner, HB9CV, in the 1950ies. The Beam is a coax-fed version of the ZL-Special. The reflector is fed 225° out of phase. The distance between the two elements is 1/8-Lambda (45°), with the two crossed phase lines of 180° results the 225°.



https://duckduckgo.com/?q=HB9CV&t=h_&ia=web

 

[nfsus]

Does anyone have any experience with this one?

 

[BJ radionut]

Diamond® Antenna ~ A502HB Base Station (diamondantenna.net)

Very close to same design set-up. I have worked a "couple" of these, last couple years.
Small design for like HOA set-up, or would be nice portable.
Don't expect much over that.
W8JK beam is a multi-band variant of this set-up.
I would build a director-driven element full size 2 element over the designed above (kinda dual Gamma match type set-up) unless the matching network is very stoutly built, power handling is an issue.

 

[nfsus]

Your 6m link above is what I've built but fir 11 meters. I dont run power so I'm not stressed about that. The gain to size ratio is what I'm interested in.

 

[BJ radionut]

Yagi 2 element (dx-antennas.com)
The Daily Antenna: So much gain for so little metal - the 2 element yagi
A 2 Element Direct Feed Yagi for Multiple bands by WB2VUO (hamuniverse.com)

Just more info...The Director/Dipole Driven element design has the best gain figures with about .11 wave spacing (little over 5dbd) I think Bill Orr's design lists 5.3 dbd
Best F/B rejection is achieved with Reflector/Dipole Driven element design (gain drops to "about" 4.5 dBd at 1/4 wave spacing) ...F/B rejection about 15db +/-
Very little change, but that's the figures I am most familiar with.
All the Best
Gary

 

[nfsus]

Supposedly this design will produce 7db gain and 30 db rejection

 

[BJ radionut]

Supposedly this design will produce 7db gain and 30 db rejection

I question that "HIGHLY"...maybe 7dbi at best...never 7dbd IMHO...
I trust Bill Orr's figures any day over most.
Optimized 2 element full size = 5 dBd +/- depending on design.

"Some manufacturers might claim they have a “special” feed system or have some other fancy way of putting things. (Like a HB9CV/ZL-special etc.) But sadly, it just isn’t possible to produce more gain on such a boom length" (Quote from first link)

dBd = dBi - 2.2(dipole gain) ...thus 6dBi = approx. 3.8 dBd ...
These are figures very close to reality, much more is someone's "Pipe" dream

 

[nfsus]

Its supposedly due to the phased elements

 

[nfsus]

Pic didnt load

 

[BJ radionut]

eHam.net

Electromagnetics, the W8JK Antenna, and the ‘Wow!’ Signal - Nerfd.net - RF News & Info

 

[BJ radionut]

Gain: 6.3 dBi
Diamond® Antenna ~ A502HB Base Station (diamondantenna.net)

The Simplest 2-Element Yagi? (antentop.org)

 

[BJ radionut]

2 Element Yagi | WorldwideDX Radio Forum

What Can We Expect From a 2-Element Beam? (antentop.org)