[TowerTalk] 80 4-square inside a 160 4-square? Pros and Cons please!

[Robert Shohet]

Hi Guys,

I want to thank W8JI, N6RK, W5VU and Jim Lux (callsign?) for their
responses.  Apparently this can be done but due to technical issues, is
rather
complex.  Having the need to use 2 antennas on 2 bands in an SO2R
contest setup makes the possibility of an 80 4 square inside of a 160 4
square, rather impractical.

Back to the drawing board - thanks for all who responded!

73
Bob KQ2M

----- Original Message ----- 
From: "Rick Karlquist" <richard at karlquist.com>
To: "Robert Shohet" <kq2m at earthlink.net>
Cc: <towertalk at contesting.com>
Sent: Thursday, June 10, 2004 9:04 PM
Subject: Re: [TowerTalk] 80 4-square inside a 160 4-square? Pros and Cons
please!


> Robert Shohet said:
> If I did this, then my existing 80 4 square
> > (inv l's) would be inside the 160 4-square.
> >
> > I can't imagine this would be good for the 80 meter 4-square
performance.
> >
> > Has anyone out there actually had an  80 4-square inside a 160 4-square
> > and
> > can tell me about actual changes in performance (that they have
observed)
> > of
> > the 80 4-square and what they were?
>
> I have 80 and 40 meter concentric 7-hex arrays.  The 80 meter
> verticals have insulators at the midpoint with latching vacuum
> relays across them.  I have to open up the relays on the 80 meter
> verticals when on 40 meters and also float them from ground.
> Failure to do this would result in severe pattern distortion on
> 40 meters.  The same general principle should apply to concentric
> 4 squares.
>
> > Are these problems (if any) worsened by using BOTH antennas at the same
> > time
> > on different bands with two different radios?  Both 4-squares would be
>
>
> Difficult.  You would have to use traps instead of relays.
> The traps would act as loading coils on 80, so you would want
> cancel the inductance with a series capacitance on 80.  This will reduce
> bandwidth, which is one reason why I don't do it that way.
>
> Rick N6RK
>
>