R: [amsat-bb] Myers' BBQ Grill

["i8cvs" <domenico.i8cvs@xxxxxx>]

Hi Pieter

The UT-141 is a Semi-rigid miniature cable with Z0=50 ohm .Since the
insulating material is teflon the Velocity Factor is  0,75
A quarter wave electrical wavelength of UT-141 at 2400 MHz is :

Free space wavelength (lambda) = 300/2400 =0.125 meters or 12,5 cm
Free space 1/4 wavelenght = 12,5/4=3,125 cm
1/4 electrical wavelenght of UT-141 = 3,125 x 0,75 =2,34 cm at 2400 MHz

73 de i8CVS Domenico



----- Original Message -----
From: Pieter Ibelings <elpieter@hotmail.com>
To: Greg Dolkas <greg@core.rose.hp.com>; <amsat-bb@AMSAT.Org>
Sent: Monday, May 14, 2001 6:39 PM
Subject: Re: [amsat-bb] Myers' BBQ Grill


> Can someone give me the details of the stub. I need to know what coax it
is
> (ut 141?) and the lengh. I will simulate it and suggest things that need
to
> be done if any.
>
> Pieter
>
> ----- Original Message -----
> From: "Greg Dolkas" <greg@core.rose.hp.com>
> To: <amsat-bb@AMSAT.Org>
> Sent: Monday, May 14, 2001 11:51
> Subject: Re: [amsat-bb] Myers' BBQ Grill
>
>
> > >
> > > Further to my query regarding the short circuit at the connector.  I
> have
> > > opened up the housing and discovered the reason for the short.   There
> is a
> > > quarter wave stub at the centre of the dipole.   The centre of the
coax
> is
> > > soldered to one side of the dipole and the braid at the shorted end of
> the
> > > stub.  Quite obviously this is a matching technique and the antenna
> should
> > > be fine at RF.
> >
> > "Fine", of course, is a relative term.  The stub was undoubtedly
designed
> > for around 2.6 ghz.  Can anybody calculate how much is lost when it is
> > run at 2.4 ghz?  I am wondering if this is a factor in why I'm having
> > such poor reception with my Lance BBQ grill and feed.  At DC it measures
> > about 1 ohm, so the construction might be similar to yours.
> >
> > My guess is that it probably isn't enough to notice, but I want to look
> > at everything.
> >
> > Thanks,
> >
> > Greg.
> > ----
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> >
> ----
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