Wireless not connecting...

[Gene Heskett]

On Friday 31 May 2019 01:02:17 pm Mike Marchywka wrote:

> On Fri, May 31, 2019 at 11:11:43AM -0400, Gene Heskett wrote:
> > On Friday 31 May 2019 08:24:05 am Mike Marchywka wrote:
> > > On Fri, May 31, 2019 at 01:33:57PM +0200, Liam Proven wrote:
> > > > On Fri, 31 May 2019 at 13:25, Oliver Grawert <ogra at ubuntu.com> 
wrote:
> > > > > distros should really consider simply shipping paperclips
> > > > > alongside these isos images ... since it seems to make all
> > > > > these firmware packages and the related driver mess obsolete
> > > > > ;)
> > > > >
> > > > :-D
> > > >
> > > > I found the tip online. I was amazed it worked and worked so
> > > > well.
> > > >
> > > > https://discussions.apple.com/thread/4037028?answerId=1867737402
> > > >2#18 677374022
> > > >
> > > > Sorry, my mistake. Not a paper clip -- the wire was too thick. A
> > > > twisty-tie, with the end of the plastic stripped off.
> > >
> > > On your way to making a conformal dielectric antenna :) Hi tech
> > > and not know it... The reason for pointing this out though is not
> > > just to use jargon but curious if there is any practical
> > > application here. RF fields can be sensitive to some things and if
> > > the front end is instrumented properly maybe there are sensor
> > > applications here- put a coil on it and make a metal detector :)
> >
> > Antennas can be spooky things at wifi frequencies.  To be correct
> > and
>
> Othewise known as sensors largely through near field coupling. There
> is high precision circuit measuring equipment but then there can also
> be simple thing integrated into the card that are not nearly
> as good but may under software control let your measure something.
>
> I'm not sure what that something would be but curious now what the
> RF sections look like. Anyone need a grid dip meter on a cell phone
> lol.
>
>
> 1/2 wave dipoles, or 1/4 plus image, have not always been practical
> and stub or short antennas are IIRC well analyzed. Anything that
> accelerates a charge radiates but you have to look at both what the
> transmitter sees as a load under many parameters and what the reciever
> sees. Generally when analyzed distance denominators are expanded and
> you can point to things like near and far fields although it is
> interesting that expansions like this have physical term-wise meaning
> but probably similar with expanding relativistic things.
>
> > stable, the circuit between the amplifier and the antenna should be
> > designed to improve the match between the antennas actual measured
> > characteristics in terms of both its resistance and its reactance.
> > It would be extremely rare to do a smith chart that shows both 50
> > ohms, and a purely resistive reactance, eg whether it looked
> > capacitive, or inductive at the test frequency.
>
> Any idea  what they can do with monolithic inductors these day?
>
relatively little other than what I read in the papers. They may work but 
generally discrete parts will give more control at the smoke test stage.

> > I might add that the test gear to make those measurements runs into
> > the 30 to 50k$ range and that translates to virtually no maker
> > having it, and likely not knowing how to run it if they did.
> >
> > Its generally considered that an  infinitely thin wire exactly 1/4
> > wavelength long is around 36 ohms. Fatter, or the wrong length can
> > make it very reactive, and diddle the ohmage from just 2 or 3 ohms
> > to as high as almost 1000 ohms  Its also modified by conductive
> > stuff within 10 wavelengths, which for wifi frequencies is several
> > feet and of course its thicker than our imaginary thin wire.
> >
> > So the circuit on the back side of that jack on the router isn't
> > always a good match, and this is true regardless of the direction,
> > which here means transmit and receive. A poorly designed circuit can
> > cost you 30 db.  Its rarely that bad, but 10 db is quite common.
> > Throw in that generally there is no ground plane. Such a wifi
> > antenna needs around 4 sq ft of ground plane to be able to describe
> > it as good. Usually the best you are going to get is the size of the
> > ground plane of the pcb in that router.
> >
> > You can mount it high on a wall, with the stick(s) on top pointing
> > up, and thats going to be about the best you can do as you will have
> > made it into a sort of half wave driven near the center of that half
> > wave.  And the directionality is concentrating the best signal area
> > into a donut laying horizontally around it.
> >
> > Best you're going to get given the limits imposed by the packaging.
> >
> > [...]

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>