[MLB-WIRELESS] Antenna Orientation

[Justin]

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
>>



To unsubscribe: send mail to majordomo at wireless.org.au
with "unsubscribe melbwireless" in the body of the message