[MLB-WIRELESS] Antenna Orientation

[rik]

the loss is relitive

if both point a and b are 45 degrees clockwise then they are at 90 degrees
to eachother therefor a 20db loss will accure

but if point a turned 45 degrees clockwise and pont b  turned 45 degrees
anti clockwise then there would be on the same plain so no loss, get it?


----- Original Message -----
From: "Justin" <littlejuz at optusnet.com.au>
To: "evilbunny" <evilbunny at sydneywireless.com>; "Matt Pearce"
<mattpearce at optusnet.com.au>
Cc: "melbourne wireless" <melbwireless at wireless.org.au>
Sent: Saturday, December 28, 2002 3:40 PM
Subject: RE: Re[2]: [MLB-WIRELESS] Antenna Orientation


> ER, not sure I got that all straight either? So if *both* ends of a ptp
link
> were turned 90 degrees, would you still get 20 db loss?
>
>  If I had my single antenna on top of my roof, and there were 10 other
> antennas only pointing at me, all on the same channel, smae power blah
blah,
> could I turn my antenna 90 degrees, and get only *one* of those 10 antenna
> pointing at me to turn 90 degrees also, and that means the signal I get
from
> that one antenna should be 20 db better than the other 9?
>
>  Did I get that right?
>
> Regards,
> Gaz.
>
>
>
>
>
> -----Original Message-----
> From: owner-melbwireless at wireless.org.au
> [mailto:owner-melbwireless at wireless.org.au]On Behalf Of evilbunny
> Sent: Friday, 27 December 2002 3:00 PM
> To: Matt Pearce
> Cc: melbourne wireless
> Subject: Re[2]: [MLB-WIRELESS] Antenna Orientation
>
>
> Hello Matt,
>
> Same answer, you only loose 20dBm by turning it 90 degrees, it's not
> complete loss, so as long as there is sufficient physical separation,
> and the signal thrown out from other antenna doesn't put your noise
> threshold up, then it is a possible solution... but if vertical is
> such a problem then polarisation possibly won't help that much, I
> doubt you can get a straight answer here without site surveying things
> properly...
>
> --
> Best regards,
>  evilbunny                            mailto:evilbunny at sydneywireless.com
>
> Isotope models get your isotope models. Carbon atoms -Tom
>
> http://www.cacert.org - Free Security Certificates
> http://www.nodedb.com - Think globally, network locally
> http://www.sydneywireless.com - Telecommunications Freedom
>
> Friday, December 27, 2002, 2:33:12 PM, you wrote:
>
> MP> Not sure if the question was properly asked so i'll slightly rephrase
> it.
> MP> If you had an area that was heavily populated by 2.4G wireless
networks
> and
> MP> you couldnt get a link running becuase all the channels were used and
> all
> MP> are running with horizontal polarization.  If I decided to put up a
PTP
> link
> MP> with someone else in that area say using a couple of 24dbi dishes and
> both
> MP> ends of the link had the dishes mounted vertically.  How would you go
in
> MP> this instance ??
>
> MP> Hope thats a little clearer.
>
> MP> Matt.
>
> MP> ----- Original Message -----
> MP> From: "evilbunny" <evilbunny at sydneywireless.com>
> MP> To: "Matt Pearce" <mattpearce at optusnet.com.au>
> MP> Cc: "melbourne wireless" <melbwireless at wireless.org.au>
> MP> Sent: Friday, December 27, 2002 1:38 PM
> MP> Subject: Re: [MLB-WIRELESS] Antenna Orientation
>
>
> >> Hello Matt,
> >>
> >> MP> Just a quick question about antenna's for those of you in the know.
> I
> >> MP> realise that antenna's normally are polarised horizontaly or
> MP> vertically, so
> >> MP> in saying that if more people with PTP links using directonal
> MP> antenna's
> >> MP> turned them 90degree's would this mean you could effectively run 2
> MP> cards on
> >> MP> the same channel right next to each other but on differently
> polarized
> >> MP> antenna's because they would not interfere with each other ??
Would
> MP> this
> >> MP> also work for tipping the antenna onto a 45degree angle ??
> >>
> >> Turning the antenna 45 degrees = 3dBm loss, turning 90 degrees = 20dBm
> >> loss, so you can *IF* you have enough physical separation between them
> >> on the mast... or 2 directionals looking the other way etc etc etc,
> >> physical separation is the key though...
> >>
> >> --
> >> Best regards,
> >>  evilbunny
mailto:evilbunny at sydneywireless.com
> >>
> >> The best kind of cat toy has a person on one end.
> >>
> >> http://www.cacert.org - Free Security Certificates
> >> http://www.nodedb.com - Think globally, network locally
> >> http://www.sydneywireless.com - Telecommunications Freedom
> >>
>
>
>
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