[TowerTalk] Fwd: Pseudo-Brewster Angle

[Hans Hammarquist]

 Partic,

It's the same Brewster's angle as you worked with building a LASER, it's just that your dielectric surface is now must more undefined. A flat piece of glass will not reflect at one specific angle while the soil has a much wider range of dielectric constant and not necessary such a flat surface.

I guess you didn't have to make the LASER cow proof either.

Hans - N2JFS

 

 

-----Original Message-----
From: Patrick Greenlee <patrick_g at windstream.net>
To: towertalk <towertalk at contesting.com>
Sent: Wed, Mar 2, 2016 5:47 pm
Subject: Re: [TowerTalk] Pseudo-Brewster Angle


Gee, I hadn't heard the term Brewster's angle in decades, not since I 
was an undergrad physics student building tunable liquid dye LASERs as a 
special project for credit.

Patrick        NJ5G

On 3/2/2016 9:50 AM, Mike & Becca Krzystyniak wrote:
> What about shorting together the circumference in a ring?
> How does that affect the angle?
>
> MK
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of N5KM
> - Kris
> Sent: Wednesday, March 02, 2016 12:07 AM
> To: towertalk at contesting.com
> Subject: [TowerTalk] Pseudo-Brewster Angle
>
> Reading the thread about an effective radial system got me thinking about
> the pseudo-Brewster angle of a 1/4 wl vertical antenna. As strictly a mental
> exercise, I calculated how much radial wire would be needed for an 80m
> vertical Fresnel zone that results in a low (1-2 degree) pseudo-Brewster
> angle. Assuming 120 radials of 5 wavelengths each that comes to 30 miles of
> wire on a parcel of at least 122 acres.
>
> The tips of the radial will be 68 feet apart. This raises the question is
> this too far apart to affect the pseudo-Brewster angle? Devoldere says yes
> (Low-Band DXing, 3rd ed.). He says they need to be no more than .05 wl (13
> feet) apart.
> The return
> currents will be nearly entirely collected by the close-in parts of the
> radials. So that's not an issue. John doesn't show the math or other
> analysis that leads to the
> .05 wl figure so I'm not entirely convinced it's needed. However, if true,
> that would require an additional 60 miles of wire.
>
> Kris N5KM
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