Strongest Wireless Channel

My laptop seems to connect to my Linksys router much stronger when
I switch the router to channel 11 from 6. Does this make sense? TIA

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On 22 May 2007 23:07:00 GMT, (E-Mail Removed) wrote:

>My laptop seems to connect to my Linksys router much stronger when
>I switch the router to channel 11 from 6. Does this make sense? TIA

one possible explanation is that there is less interference on that
channel.

JeB <(E-Mail Removed)> wrote:
> On 22 May 2007 23:07:00 GMT, (E-Mail Removed) wrote:
>
> >My laptop seems to connect to my Linksys router much stronger when
> >I switch the router to channel 11 from 6. Does this make sense? TIA
>
> one possible explanation is that there is less interference on that
> channel.

I thought about that but I am new to this and you guys are the
the experts here. Thank you for the reply.

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<(E-Mail Removed)> wrote in message
news:20070522212830.117$(E-Mail Removed)...
> JeB <(E-Mail Removed)> wrote:
>> On 22 May 2007 23:07:00 GMT, (E-Mail Removed) wrote:
>>
>> >My laptop seems to connect to my Linksys router much stronger when
>> >I switch the router to channel 11 from 6. Does this make sense? TIA
>>
>> one possible explanation is that there is less interference on that
>> channel.
>
> I thought about that but I am new to this and you guys are the
> the experts here. Thank you for the reply.
>
Everyones circumstances are different.

Thank you for reporting your findings, it could definitely help someone
else.

(E-Mail Removed) hath wroth:

>My laptop seems to connect to my Linksys router much stronger when
>I switch the router to channel 11 from 6. Does this make sense? TIA

Not really. How much stronger? What hardware? External aftermarket
antennas? Home made antennas?

Most very high gain (19-24dBi) antennas just barely have enough
bandwidth to cover the 83.5MHz width of the 2.4GHz band. Same with
some really tiny ceramic substrate 2.4GHz antennas. Typically, they
will have about a 3dB gain variation across the band. However, this
is not the case with typical 2dBi vertical coaxial and colinear
antennas which have more than adequate bandwidth. There are also
ceramic bandpass filters on the antenna connection of most access
points and some client adapters to reduce interference from adjacent
services. These are not all that flat across the band and do vary
with production lots. There is also usually a matching network
between the antenna and the PIN diode diversity switch, which can also
be frequency sensitive. In other words, there are plenty of
components that can cause differences in gain across the band.

For a good clue, search the FCC ID web site for your unspecified model
hardware and look at the test report. You'll see that the transmit
power varies somewhat across the band. The receiver sensitivity does
the same thing, but that's not in the report.




--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Jeff Liebermann <(E-Mail Removed)> wrote:
> (E-Mail Removed) hath wroth:
>
> >My laptop seems to connect to my Linksys router much stronger when
> >I switch the router to channel 11 from 6. Does this make sense? TIA
>
> Not really. How much stronger? What hardware? External aftermarket
> antennas? Home made antennas?
>
> Most very high gain (19-24dBi) antennas just barely have enough
> bandwidth to cover the 83.5MHz width of the 2.4GHz band. Same with
> some really tiny ceramic substrate 2.4GHz antennas. Typically, they
> will have about a 3dB gain variation across the band. However, this
> is not the case with typical 2dBi vertical coaxial and colinear
> antennas which have more than adequate bandwidth. There are also
> ceramic bandpass filters on the antenna connection of most access
> points and some client adapters to reduce interference from adjacent
> services. These are not all that flat across the band and do vary
> with production lots. There is also usually a matching network
> between the antenna and the PIN diode diversity switch, which can also
> be frequency sensitive. In other words, there are plenty of
> components that can cause differences in gain across the band.
>
> For a good clue, search the FCC ID web site for your unspecified model
> hardware and look at the test report. You'll see that the transmit
> power varies somewhat across the band. The receiver sensitivity does
> the same thing, but that's not in the report.


I am using a Senoa PCMCIA card with the 2500 something chipset
and a 40 inch omni antenna purchased from Pasadena Wireless. It is
mounted on the roof with no structures in the way. The signal I am
speaking of is a Linksys router WRT54G and when it's on 6 windows
says the signal is low. On channel 11 it goes up to good but mostly
very good. I may not make sense but I am telling the truth.
Thanks for the input.

--
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(E-Mail Removed) wrote:
> Jeff Liebermann <(E-Mail Removed)> wrote:
>
>>(E-Mail Removed) hath wroth:
>>
>>
>>>My laptop seems to connect to my Linksys router much stronger when
>>>I switch the router to channel 11 from 6. Does this make sense? TIA
>>
>>Not really. How much stronger? What hardware? External aftermarket
>>antennas? Home made antennas?
>>
>>Most very high gain (19-24dBi) antennas just barely have enough
>>bandwidth to cover the 83.5MHz width of the 2.4GHz band. Same with
>>some really tiny ceramic substrate 2.4GHz antennas. Typically, they
>>will have about a 3dB gain variation across the band. However, this
>>is not the case with typical 2dBi vertical coaxial and colinear
>>antennas which have more than adequate bandwidth. There are also
>>ceramic bandpass filters on the antenna connection of most access
>>points and some client adapters to reduce interference from adjacent
>>services. These are not all that flat across the band and do vary
>>with production lots. There is also usually a matching network
>>between the antenna and the PIN diode diversity switch, which can also
>>be frequency sensitive. In other words, there are plenty of
>>components that can cause differences in gain across the band.
>>
>>For a good clue, search the FCC ID web site for your unspecified model
>>hardware and look at the test report. You'll see that the transmit
>>power varies somewhat across the band. The receiver sensitivity does
>>the same thing, but that's not in the report.
>
>
>
> I am using a Senoa PCMCIA card with the 2500 something chipset
> and a 40 inch omni antenna purchased from Pasadena Wireless. It is
> mounted on the roof with no structures in the way. The signal I am
> speaking of is a Linksys router WRT54G and when it's on 6 windows
> says the signal is low. On channel 11 it goes up to good but mostly
> very good. I may not make sense but I am telling the truth.
> Thanks for the input.
>
Hi,
Maybe the antenna is tuned to chnnel 11?

(E-Mail Removed) hath wroth:

>I am using a Senoa PCMCIA card with the 2500 something chipset
>and a 40 inch omni antenna purchased from Pasadena Wireless.

A 40 inch long omni antenna is going to have a gain of about 10dBi.
That's fairly high gain for such an omni and will probably have a
correspondingly narrow bandwidth. I'm too lazy to search for all the
possible 40" long antennas carried by WlanParts. Is it one of these?
<http://www.wlanparts.com/category/antennas/>
Well, I got lucky. This one is 39" long:
<http://www.wlanparts.com/product/GP-24S>
Unfortunately, the data sheet does not include a gain vs frequency, or
VSWR vs frequency graph. Same problem on the Comet Antenna (NCG) web
pile.

Ok, so I have to do some guesswork. The VSWR of such an antenna is
probably fairly symmetrical across the band in free space. However,
when mounted improperly, such as too close to a tower, pipe, wall,
etc, the antenna changes resonance, usually going down in resonant
frequency. That's backwards for what you're seeing, so that's
probably not the problem.

That leaves the various filters, board traces, and matching systems in
your Senao wireless device. I can't tell how well those are working
without putting the radio on the bench. I have little experience with
Senao. However, I can assure you that other vendors products vary
substantially across the 83.5Mhz of the 2.4Ghz band. I can possibly
dig out some old test data if you're interested.

It also shows up in the test data. See the tx power data for the
Senao 2511 at:
<https://gullfoss2.fcc.gov/prod/oet/forms/blobs/retrieve.cgi?attachment_id=229884&native_or_pdf=pd f>
in Page 13.
Channel Freq dBm Limit Pass/fail
1 2412 15.48 30 PASS
6 2437 15.00 30 PASS
11 2462 14.11 30 PASS
Note the 1.3dB difference in tx power output between channels 1 and
11. That's not very much, but that's under ideal conditions, without
the resonant effects of the antenna, bandpass filters, matching
networks, receiver, etc. This is also probably a hand tweaked unit.

>It is
>mounted on the roof with no structures in the way.

Ok, that eliminates any detuneing of the antenna by nearby metal.
Figure on staying about 10 wavelengths (125cm) away from the antenna.

>The signal I am
>speaking of is a Linksys router WRT54G and when it's on 6

Are you reading the signal strength on the WRT54G status page or on
the Senao wireless something or other?

Incidentally, some clients and AP's yield different signal strengths
when moving data than when at idle. That's because they like to
change data speed with and without data, which causes some differences
in indicated signal strength.

>windows
>says the signal is low.

Ok, so the mystery Senao device is plugged directly into a Windoze
computah. I don't suppose it would be particularly difficult for you
to identify what hardware you own?

>On channel 11 it goes up to good but mostly
>very good. I may not make sense but I am telling the truth.
>Thanks for the input.

There are too many variables to determine the culprit. I've seen
something similar with home made (or badly made) antennas and
equipment. It also happens with very badly built pigtails,
connectors, and adapters. Without a bench setup and a pile of test
equipment, it's difficult to isolate. The easiest way for you do
determine the culprit is to substitute parts and pieces of your
equipment and see if it also happens with other access points and
clients.

--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

The antenna was advertised as 15db for $66.00.
Here is the unit I bought:

http://www.wlanparts.com/product/O2415

It seems to work pretty good compared to rubber duck type I
have used. Thanks for all of the input.

BTW, what is the best PCMCIA card? Is a 300mw better than my 200?



Jeff Liebermann <(E-Mail Removed)> wrote:
> (E-Mail Removed) hath wroth:
>
> >I am using a Senoa PCMCIA card with the 2500 something chipset
> >and a 40 inch omni antenna purchased from Pasadena Wireless.
>
> A 40 inch long omni antenna is going to have a gain of about 10dBi.
> That's fairly high gain for such an omni and will probably have a
> correspondingly narrow bandwidth. I'm too lazy to search for all the
> possible 40" long antennas carried by WlanParts. Is it one of these?
> <http://www.wlanparts.com/category/antennas/>
> Well, I got lucky. This one is 39" long:
> <http://www.wlanparts.com/product/GP-24S>
> Unfortunately, the data sheet does not include a gain vs frequency, or
> VSWR vs frequency graph. Same problem on the Comet Antenna (NCG) web
> pile.
>
> Ok, so I have to do some guesswork. The VSWR of such an antenna is
> probably fairly symmetrical across the band in free space. However,
> when mounted improperly, such as too close to a tower, pipe, wall,
> etc, the antenna changes resonance, usually going down in resonant
> frequency. That's backwards for what you're seeing, so that's
> probably not the problem.
>
> That leaves the various filters, board traces, and matching systems in
> your Senao wireless device. I can't tell how well those are working
> without putting the radio on the bench. I have little experience with
> Senao. However, I can assure you that other vendors products vary
> substantially across the 83.5Mhz of the 2.4Ghz band. I can possibly
> dig out some old test data if you're interested.
>
> It also shows up in the test data. See the tx power data for the
> Senao 2511 at:
> <https://gullfoss2.fcc.gov/prod/oet/f...i?attachment_i
> d=229884&native_or_pdf=pdf> in Page 13.
> Channel Freq dBm Limit Pass/fail
> 1 2412 15.48 30 PASS
> 6 2437 15.00 30 PASS
> 11 2462 14.11 30 PASS
> Note the 1.3dB difference in tx power output between channels 1 and
> 11. That's not very much, but that's under ideal conditions, without
> the resonant effects of the antenna, bandpass filters, matching
> networks, receiver, etc. This is also probably a hand tweaked unit.
>
> >It is
> >mounted on the roof with no structures in the way.
>
> Ok, that eliminates any detuneing of the antenna by nearby metal.
> Figure on staying about 10 wavelengths (125cm) away from the antenna.
>
> >The signal I am
> >speaking of is a Linksys router WRT54G and when it's on 6
>
> Are you reading the signal strength on the WRT54G status page or on
> the Senao wireless something or other?
>
> Incidentally, some clients and AP's yield different signal strengths
> when moving data than when at idle. That's because they like to
> change data speed with and without data, which causes some differences
> in indicated signal strength.
>
> >windows
> >says the signal is low.
>
> Ok, so the mystery Senao device is plugged directly into a Windoze
> computah. I don't suppose it would be particularly difficult for you
> to identify what hardware you own?
>
> >On channel 11 it goes up to good but mostly
> >very good. I may not make sense but I am telling the truth.
> >Thanks for the input.
>
> There are too many variables to determine the culprit. I've seen
> something similar with home made (or badly made) antennas and
> equipment. It also happens with very badly built pigtails,
> connectors, and adapters. Without a bench setup and a pile of test
> equipment, it's difficult to isolate. The easiest way for you do
> determine the culprit is to substitute parts and pieces of your
> equipment and see if it also happens with other access points and
> clients.

--
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Tony Hwang <(E-Mail Removed)> wrote:
> (E-Mail Removed) wrote:
> > Jeff Liebermann <(E-Mail Removed)> wrote:
> >
> >>(E-Mail Removed) hath wroth:
> >>
> >>
> >>>My laptop seems to connect to my Linksys router much stronger when
> >>>I switch the router to channel 11 from 6. Does this make sense? TIA
> >>
> >>Not really. How much stronger? What hardware? External aftermarket
> >>antennas? Home made antennas?
> >>
> >>Most very high gain (19-24dBi) antennas just barely have enough
> >>bandwidth to cover the 83.5MHz width of the 2.4GHz band. Same with
> >>some really tiny ceramic substrate 2.4GHz antennas. Typically, they
> >>will have about a 3dB gain variation across the band. However, this
> >>is not the case with typical 2dBi vertical coaxial and colinear
> >>antennas which have more than adequate bandwidth. There are also
> >>ceramic bandpass filters on the antenna connection of most access
> >>points and some client adapters to reduce interference from adjacent
> >>services. These are not all that flat across the band and do vary
> >>with production lots. There is also usually a matching network
> >>between the antenna and the PIN diode diversity switch, which can also
> >>be frequency sensitive. In other words, there are plenty of
> >>components that can cause differences in gain across the band.
> >>
> >>For a good clue, search the FCC ID web site for your unspecified model
> >>hardware and look at the test report. You'll see that the transmit
> >>power varies somewhat across the band. The receiver sensitivity does
> >>the same thing, but that's not in the report.
> >
> >
> >
> > I am using a Senoa PCMCIA card with the 2500 something chipset
> > and a 40 inch omni antenna purchased from Pasadena Wireless. It is
> > mounted on the roof with no structures in the way. The signal I am
> > speaking of is a Linksys router WRT54G and when it's on 6 windows
> > says the signal is low. On channel 11 it goes up to good but mostly
> > very good. I may not make sense but I am telling the truth.
> > Thanks for the input.
> >
> Hi,
> Maybe the antenna is tuned to chnnel 11?

The specs didn't say that was the case. Here is the link:

http://www.wlanparts.com/product/O2415

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