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WRT54GS and external antenna...

Author
1 Mar 2005 11:16 AM
Tor Tveitane
Hi,

I need to use a Linksys WRT54GS for a wireless link of 4kms.  This device
has two small antennas.

How do I unscrew / unmount these original antennas and to which connector do
I connect my external 24dBi grid antenna?

Thanks for tips on this issue

best regards

tor

Author
1 Mar 2005 1:18 PM
f/fgeorge
Show quote Hide quote
On Tue, 1 Mar 2005 12:16:19 +0100, "Tor Tveitane" <ep***@bushsoft.com>
wrote:

>Hi,
>
>I need to use a Linksys WRT54GS for a wireless link of 4kms.  This device
>has two small antennas.
>
>How do I unscrew / unmount these original antennas and to which connector do
>I connect my external 24dBi grid antenna?
>
>Thanks for tips on this issue
>
>best regards
>
>tor
>
They just unscrew, but one of mine is stuck! There is a large black
piece that covers the actual screw in piece but the alrge black
covering is hard plastic and does not get out of the way. Grab the
largest part(biggest around) of the antenna and try to unscrew it. One
of mine came off but as I said I cannot get the other one off.
Author
1 Mar 2005 1:25 PM
Thomas Krüger
f/fgeorge wrote:

> On Tue, 1 Mar 2005 12:16:19 +0100, "Tor Tveitane" <ep***@bushsoft.com>
> wrote:

>>How do I unscrew / unmount these original antennas

> They just unscrew, but one of mine is stuck! There is a large black
> piece that covers the actual screw in piece but the alrge black
> covering is hard plastic and does not get out of the way. Grab the
> largest part(biggest around) of the antenna and try to unscrew it. One
> of mine came off but as I said I cannot get the other one off.

The "large part" can be pulled off.

Thomas
Author
1 Mar 2005 2:05 PM
Tor Tveitane
"f/fgeorge" <ffgeo***@yourplace.com> skrev i melding
news:3oq821d04eaaipmcig0mq0bqrj51t7vtjk@4ax.com...

> They just unscrew, but one of mine is stuck! There is a large black
> piece that covers the actual screw in piece but the alrge black
> covering is hard plastic and does not get out of the way. Grab the
> largest part(biggest around) of the antenna and try to unscrew it. One
> of mine came off but as I said I cannot get the other one off.

OK,
thanks for that info, but what about connecting ONE external antenna to TWO
antenna connectors?  How do I get full power out  / in to the external
antenna from this router??

Tor
Author
1 Mar 2005 2:11 PM
Peter Pan
Tor Tveitane wrote:
Show quoteHide quote
> "f/fgeorge" <ffgeo***@yourplace.com> skrev i melding
> news:3oq821d04eaaipmcig0mq0bqrj51t7vtjk@4ax.com...
>
>> They just unscrew, but one of mine is stuck! There is a large black
>> piece that covers the actual screw in piece but the alrge black
>> covering is hard plastic and does not get out of the way. Grab the
>> largest part(biggest around) of the antenna and try to unscrew it.
>> One of mine came off but as I said I cannot get the other one off.
>
> OK,
> thanks for that info, but what about connecting ONE external antenna
> to TWO antenna connectors?  How do I get full power out  / in to the
> external antenna from this router??
>
> Tor

You don't...
There is a splitter inside that splits the output from the transmitter to
the two antennas. You can either combine em back together, or open the unit
up and bypass the splitter.
Author
1 Mar 2005 2:26 PM
Tor Tveitane
"Peter Pan" <Marcs1102NOSPAM@HotmailNOSPAM.com> skrev i melding
news:38jbg8F5n7eulU1@individual.net...

> You don't...
> There is a splitter inside that splits the output from the transmitter to
> the two antennas. You can either combine em back together, or open the
> unit up and bypass the splitter.

OK, thanks for this info.  How much (in dB) do I loose if I use an external
combiner and where do I get a suitable such device?

Thanks again for tips

Tor
Author
1 Mar 2005 4:02 PM
Peter Pan
Tor Tveitane wrote:
Show quoteHide quote
> "Peter Pan" <Marcs1102NOSPAM@HotmailNOSPAM.com> skrev i melding
> news:38jbg8F5n7eulU1@individual.net...
>
>> You don't...
>> There is a splitter inside that splits the output from the
>> transmitter to the two antennas. You can either combine em back
>> together, or open the unit up and bypass the splitter.
>
> OK, thanks for this info.  How much (in dB) do I loose if I use an
> external combiner and where do I get a suitable such device?
>
> Thanks again for tips
>
> Tor

Don't know where to get one... I have seen external antenna packs that have
two antennas and go to both on the unit, and have opened my unit up to make
it just one output, I was told that you can't have an impedence mismatch
between the two outputs past the splitter, and there are two of em to
balance things out and cut down dead spots.. Since I wanted to use an
external antenna, I just tapped into the output before the splitter.
Author
1 Mar 2005 4:07 PM
Tor Tveitane
"Peter Pan" <Marcs1102NOSPAM@HotmailNOSPAM.com> skrev i melding
news:38ji0iF5n5nvrU1@individual.net...

> Don't know where to get one... I have seen external antenna packs that
have
> two antennas and go to both on the unit, and have opened my unit up to
make
> it just one output, I was told that you can't have an impedence mismatch
> between the two outputs past the splitter, and there are two of em to
> balance things out and cut down dead spots.. Since I wanted to use an
> external antenna, I just tapped into the output before the splitter.

Thanks for this info.  Since you have 'been there and done that'::

What kind of connection is used between the sender and the splitter.  Is it
soldered or some kind of coax plug which can be 'cleanly' connected to a
pigtail cable?

Tor
Author
1 Mar 2005 4:22 PM
Peter Pan
Tor Tveitane wrote:
Show quoteHide quote
> "Peter Pan" <Marcs1102NOSPAM@HotmailNOSPAM.com> skrev i melding
> news:38ji0iF5n5nvrU1@individual.net...
>
>> Don't know where to get one... I have seen external antenna packs
>> that have two antennas and go to both on the unit, and have opened
>> my unit up to make it just one output, I was told that you can't
>> have an impedence mismatch between the two outputs past the
>> splitter, and there are two of em to balance things out and cut down
>> dead spots.. Since I wanted to use an external antenna, I just
>> tapped into the output before the splitter.
>
> Thanks for this info.  Since you have 'been there and done that'::
>
> What kind of connection is used between the sender and the splitter.
> Is it soldered or some kind of coax plug which can be 'cleanly'
> connected to a pigtail cable?
>
> Tor

It was soldered.. I just added a mini-uhf thru the case connector, cut the
lead and soldered it to the new output connector.

somewhere on the internet are pictures of the inside of the device... I
don't happen to recall the links (maybe someone here knows em, or a search
can find em).. Amazing... since the advent of digital cameras there seems to
be a plethora of people doing autopsies on things and posting the photos....

PS In case you are curious, they don't bleed when you cut em :)
Author
1 Mar 2005 4:46 PM
Tor Tveitane
"Peter Pan" <Marcs1102NOSPAM@HotmailNOSPAM.com> skrev i melding
news:38jj69F5n8ed6U1@individual.net...

> PS In case you are curious, they don't bleed when you cut em :)

ROTFL

I'm an electronics engineer and I'm definately not afraid of opening black
boxes and modifying them.  However this is a brand new box and I would just
like to know a few details before I go in and break the warranty ;-)

Thanks for all your info Peter

Tor
Author
1 Mar 2005 4:48 PM
Peter Pan
Peter Pan wrote:
Show quoteHide quote
> Tor Tveitane wrote:
>> "Peter Pan" <Marcs1102NOSPAM@HotmailNOSPAM.com> skrev i melding
>> news:38ji0iF5n5nvrU1@individual.net...
>>
>>> Don't know where to get one... I have seen external antenna packs
>>> that have two antennas and go to both on the unit, and have opened
>>> my unit up to make it just one output, I was told that you can't
>>> have an impedence mismatch between the two outputs past the
>>> splitter, and there are two of em to balance things out and cut down
>>> dead spots.. Since I wanted to use an external antenna, I just
>>> tapped into the output before the splitter.
>>
>> Thanks for this info.  Since you have 'been there and done that'::
>>
>> What kind of connection is used between the sender and the splitter.
>> Is it soldered or some kind of coax plug which can be 'cleanly'
>> connected to a pigtail cable?
>>
>> Tor
>
> It was soldered.. I just added a mini-uhf thru the case connector,
> cut the lead and soldered it to the new output connector.
>
> somewhere on the internet are pictures of the inside of the device...
> I don't happen to recall the links (maybe someone here knows em, or a
> search can find em).. Amazing... since the advent of digital cameras
> there seems to be a plethora of people doing autopsies on things and
> posting the photos....
> PS In case you are curious, they don't bleed when you cut em :)

Didn't find the actual autopsy photos, but there is a forum/website for
linksys stuff (www.linksysinfo.org)
and the message with the links to autopsy info
http://www.linksysinfo.org/modules.php?name=Forums&file=viewtopic&t=169

(text of the page)
WRT54G v WRT54GS Hardware Differences - The Autopsy
Posted: Thu 17 Jun , 2004 18:59



Its been requested that we post a sticky with a link to our autopsy of the
differences between the four hardware versions of the WRT54G and WRT54GS

The Definitive Autospy can be found here - Autopsy: Linksys WRT54G/GS
Hardware Versions Under the Knife

It covers the versions:
WRT54G v1
WRT54G v1.1
WRT54G v2.0
WRT54GS

We hope to do the same for WAP54G when we acquire the varied units as well
as compare them to the WRT54G.


____________

(note, for the actual link you have to go to the page)
Author
1 Mar 2005 4:23 PM
riggor9999
These are diversity antennas - which means the one with the better signal
will be used fro client - but not both at the same time.

I disconnected both, and connected a new antenna just to one - it works
fine.

In the admin pages - you can control the config of the antennas.

Go get the Linksys documentation form their web site for more info...


Show quoteHide quote
"Tor Tveitane" <ep***@bushsoft.com> wrote in message
news:38jiahF5nmue3U1@individual.net...
> "Peter Pan" <Marcs1102NOSPAM@HotmailNOSPAM.com> skrev i melding
> news:38ji0iF5n5nvrU1@individual.net...
>
>> Don't know where to get one... I have seen external antenna packs that
> have
>> two antennas and go to both on the unit, and have opened my unit up to
> make
>> it just one output, I was told that you can't have an impedence mismatch
>> between the two outputs past the splitter, and there are two of em to
>> balance things out and cut down dead spots.. Since I wanted to use an
>> external antenna, I just tapped into the output before the splitter.
>
> Thanks for this info.  Since you have 'been there and done that'::
>
> What kind of connection is used between the sender and the splitter.  Is
> it
> soldered or some kind of coax plug which can be 'cleanly' connected to a
> pigtail cable?
>
> Tor
>
>
Author
1 Mar 2005 5:02 PM
Tor Tveitane
"riggor9999" <riggor9***@invalid.yahoo.com> skrev i melding
news:J8CdnSyt9JCfCrnfRVn-1g@comcast.com...

> These are diversity antennas - which means the one with the better signal
> will be used fro client - but not both at the same time.
>
> I disconnected both, and connected a new antenna just to one - it works
> fine.

Aha, I have the sveasoft firmware, there are options for RX antenna: auto /
left / right and the same for TX antenna.  Does this mean that I can set
both TX and RX antenna to right and connect my external antenna to the right
socket and all is well ??

Sounds too good to be true ;-)

Can I have a comment on this (and how much power I loose by this method
compared to opening the box and solder a connector directly to the TX output
terminal).

Tor
Author
1 Mar 2005 6:19 PM
Floyd L. Davidson
Show quote Hide quote
"Tor Tveitane" <ep***@bushsoft.com> wrote:
>"riggor9999" <riggor9***@invalid.yahoo.com> skrev i melding
>news:J8CdnSyt9JCfCrnfRVn-1g@comcast.com...
>
>> These are diversity antennas - which means the one with the better signal
>> will be used fro client - but not both at the same time.
>>
>> I disconnected both, and connected a new antenna just to one - it works
>> fine.
>
>Aha, I have the sveasoft firmware, there are options for RX antenna: auto /
>left / right and the same for TX antenna.  Does this mean that I can set
>both TX and RX antenna to right and connect my external antenna to the right
>socket and all is well ??
>
>Sounds too good to be true ;-)

It is exactly what you can do!  Or you can effectively do the
same thing by simply removing one antenna.  It will then never
have the best receive signal, and therefore will never be
selected for either receiver or transmit.

But with any of the 3rd party firmware upgrades the antenna
selection can be forced.

>Can I have a comment on this (and how much power I loose by this method
>compared to opening the box and solder a connector directly to the TX output
>terminal).

I see no purpose whatever in doing a hardware modification.  You
lose *nothing* by either removing one antenna or locking the
switch to one or the other of the two antennas.

By modifying the hardware you lose the option of easily going
back to a diversity configuration at some point in the future.

--
Floyd L. Davidson           <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska)                         fl***@barrow.com
Author
1 Mar 2005 5:08 PM
Jeff Liebermann
On Tue, 1 Mar 2005 06:11:15 -0800, "Peter Pan"
<Marcs1102NOSPAM@HotmailNOSPAM.com> wrote:

>There is a splitter inside that splits the output from the transmitter to
>the two antennas. You can either combine em back together, or open the unit
>up and bypass the splitter.

Nope.  It's not a splitter, power divider, Wilkinson combiner,
co-phasing contraption, or any such device.  It's a switch that is
part of the diversity reception circuit.  The radio section is
connected to only one antenna at a time. 

If you look at the photograph of the WRT54GS at:
  http://www.linksysinfo.org/modules/Content/Autopsy/WRT54GS-mblg.jpg
you'll notice the traces and coax cable coming from the antennas,
which converge at the switch IC.  The switch is controlled by the
radio which builds a table of MAC addresses and which antenna received
the last complete packet from that MAC address (or other such
algorithm).  When not associated with any client, the radio just scans
between the two antennas looking for suitable packets.  With various
alternative firmware for the WRT54G, the scanning can be disabled and
the radio permanently connected to one antenna. 

It doesn't hurt to leave an outside antenna connected to one port,
while the insipid rubber ducky antenna is left connected to the other.
I use this arrangement at my house.  The outside antenna goes to an
8dBi omni, for the neighbors to use, while the rubber ducky takes care
of my laptop connections inside.


--
Jeff Liebermann    je***@comix.santa-cruz.ca.us
150 Felker St #D   http://www.LearnByDestroying.com
Santa Cruz CA 95060    AE6KS  831-336-2558