Re: 3cm and 6cm dualband feed.


john pieniadz <johnak4mw@...>
 

Alan:  I agree with your big bang fact, God ,Selah "think on this thing" You say nothing in the cloud!  I know you are talking about internet. But He will be returning in the clouds..
 73 john AK4MW

Can you make a tapered slot SWA array? intechopen.com

On Mon, Oct 19, 2020 at 1:02 AM Alan Beard <beardal@...> wrote:
Hi guys,

Well, I built it, double size to get to 1.3 GHz where I want it.

The feed balun is just a short piece of 50 ohm coax in a box underneath
going to a BNC socket.

Analysis with a PocketVNA.

Any comments?

Alan VK2ZIW

Yes it radiates but the Return Loss is horrible.

On Sun, 11 Oct 2020 06:44:47 +1000, Alan Beard wrote
>
>

>
>

> > And we could get quite a discussion going on just where the phase center is.
>
>

> Isn't this what their antenna is designed for, the phase centre being as close as
> possible over a wide range of frequency for radar?
>
>

> Back to my suggestion re feed, actually to make it very easy to build.
>
>

> Alan VK2ZIW 
>
>

>
>
On Fri, 9 Oct 2020 21:30:14 +0000 (UTC), KENT BRITAIN wrote

> > That is an Ultra Wideband Loop antenna.  Been around for quite some time.
> > Even that paper is 9 years old.
> >
> > Note that the SWR is plotted in both frequency and Nano Seconds.
> >
> > I'm not saying you cannot make it into a dish feed, but it would take a lot of work.
> > Reflector spacing that works for 6 cm would be a poor choice for 3 cm.
> > And we could get quite a discussion going on just where the phase center is.
> >
> > Several simpler choices that are already 50 Ohm match over a broad range of
> > frequencies.        Kent WA5VJB/2E0VAA/G8EMY
> >
> > On Friday, October 9, 2020, 4:12:54 PM CDT, Alan Beard <beardal@...> wrote:
> >
> > Have you seen this, the Shorted Bow Tie?
> >
> > https://core.ac.uk/download/pdf/70589636.pdf
> >

> > Now, note the back plane, could it be a Corner Reflector?
> >

> > As, I'm not short of "space" as in the medical use of this antenna type,
> > a 90 deg corner with the petals coming out at 60 deg ie. 15 deg off the sides.
> >

> > Next, the balun. (Why?)
> >

> > With thin coax, 1/8 in. hardline, come through the backplane and wrap it around the centreline
> > of the petal down to it's tip where the outer is soldered onto it's petal and the inner goes to the
> > tip of the other petal. 

> >

> > Ah, these antenna gurus miss the obvious.
> >

> > The feed impedance, this is a bit confusing, one article, around 30 ohms balanced feed, the other,  2x 50 ohms
> > with the petals modified wider rounded at the tip.
> >

> > Any thoughts?
> >

> > Alan VK2ZIW
> >

> > On Wed, 07 Oct 2020 23:23:05 -0700, Daniel DL3IAE wrote
> ... and if you switch both coaxial relays together, isolation is not a problem.
> Requires just a single sequenzer.
>
> Daniel
>
> ---------------------------------------------------
> Alan VK2ZIW
>
> OpenWebMail 2.53, nothing in the cloud.
>
>

---------------------------------------------------
Alan VK2ZIW
Before the Big Bang, God, Sela.
OpenWebMail 2.53, nothing in the cloud.

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