TX Power

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joscollin
DD-WRT Novice


Joined: 12 Jan 2013
Posts: 10

PostPosted: Tue Feb 12, 2013 3:23    Post subject: TX Power Reply with quote
Hello,

The TX Power in my dd-wrt shows the value 70. Is it a safe value? I want the wireless only within 10 meters. So what is the best value ? (considering good performance and safety for my router WRT54G V8 )

Thanks,
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tatsuya46
DD-WRT Guru


Joined: 03 Jan 2010
Posts: 2323
Location: Winnipeg, Canada

PostPosted: Tue Feb 12, 2013 3:47    Post subject: Reply with quote
Thats fine, try 50 or 40 if you want less range but theres also hiding SSID/MAC filtering/strict DHCP settings etc that are also effective as less TX power may mean less throughput at the same working range even though SNR is still good.
_________________
[QUALCOMM ATHEROS] D-Link DIR-825 B1 -----------> DD-WRT v24-sp2 (12/15/14) std - build 25648
[QUALCOMM ATHEROS] TP-LINK TL-WDR4900 v1.3 --> DD-WRT v24-sp2 (12/22/14) std - build 25697 (private test)
[QUALCOMM ATHEROS] NETGEAR WNDR3700 v1 -----> DD-WRT v24-sp2 (12/22/14) std - build 25697 (private test)
[QUALCOMM ATHEROS] NETGEAR WNDR4300 v1 -----> DD-WRT v24-sp2 (12/22/14) std - build 25697 (private test)

LATEST FIRMWARE(S) --> ftp://ftp.dd-wrt.com/betas/
Qualcomm Atheros Wi-Fi Settings --> http://dd-wrt.com/wiki/index.php/QCA_wireless_settings
Qualcomm Atheros Client/Repeater Bridge --> http://dd-wrt.com/wiki/index.php/Repeater_Bridge#Qualcomm_Atheros

BrainSlayer wrote:
we just do it since we do not like any restrictions enforced by stupid cocaine snorting managers
joscollin
DD-WRT Novice


Joined: 12 Jan 2013
Posts: 10

PostPosted: Tue Feb 12, 2013 4:44    Post subject: Reply with quote
tatsuya46 wrote:
theres also hiding SSID/MAC filtering/strict DHCP settings etc that are also effective

If I disable SSID broadcast, even I won't be able to connect. So I have enabled it always. I am using MAC Filtering. I don't know what is "strict DHCP".

Quote:
as less TX power may mean less throughput at the same working range even though SNR is still good.


I don't understand what you mean exactly. I thought of reducing the TX Power, as the use of wireless is only within my office rooms. I don't use it for long distance. There is no such need at all.
tatsuya46
DD-WRT Guru


Joined: 03 Jan 2010
Posts: 2323
Location: Winnipeg, Canada

PostPosted: Tue Feb 12, 2013 4:48    Post subject: Reply with quote
joscollin wrote:
tatsuya46 wrote:
theres also hiding SSID/MAC filtering/strict DHCP settings etc that are also effective

If I disable SSID broadcast, even I won't be able to connect. So I have enabled it always. I am using MAC Filtering. I don't know what is "strict DHCP".

Quote:
as less TX power may mean less throughput at the same working range even though SNR is still good.


I don't understand what you mean exactly. I thought of reducing the TX Power, as the use of wireless is only within my office rooms. I don't use it for long distance. There is no such need at all.


With SSID broadcast off all devices that know the SSID still connect, it will just appear as [hidden] to unknown devices, you have to manually input the SSID to the client.

If client A is 20ft from the router with a SNR of 50, say dropping TX power reduced SNR to 45, both are still good but the max throughput may drop as well lets say 25Mbps becomes 21Mbps for ex.

"Strict DHCP" is setting max DHCP users to 0, therefor only static leases go out, even if you were to have wifi encryption off & SSID broadcast on & stranger connects, that user will not get a DHCP lease = no IP from router = no internet.

_________________
[QUALCOMM ATHEROS] D-Link DIR-825 B1 -----------> DD-WRT v24-sp2 (12/15/14) std - build 25648
[QUALCOMM ATHEROS] TP-LINK TL-WDR4900 v1.3 --> DD-WRT v24-sp2 (12/22/14) std - build 25697 (private test)
[QUALCOMM ATHEROS] NETGEAR WNDR3700 v1 -----> DD-WRT v24-sp2 (12/22/14) std - build 25697 (private test)
[QUALCOMM ATHEROS] NETGEAR WNDR4300 v1 -----> DD-WRT v24-sp2 (12/22/14) std - build 25697 (private test)

LATEST FIRMWARE(S) --> ftp://ftp.dd-wrt.com/betas/
Qualcomm Atheros Wi-Fi Settings --> http://dd-wrt.com/wiki/index.php/QCA_wireless_settings
Qualcomm Atheros Client/Repeater Bridge --> http://dd-wrt.com/wiki/index.php/Repeater_Bridge#Qualcomm_Atheros

BrainSlayer wrote:
we just do it since we do not like any restrictions enforced by stupid cocaine snorting managers
joscollin
DD-WRT Novice


Joined: 12 Jan 2013
Posts: 10

PostPosted: Tue Feb 12, 2013 5:22    Post subject: Reply with quote
Quote:
With SSID broadcast off all devices that know the SSID still connect, it will just appear as [hidden] to unknown devices, you have to manually input the SSID to the client.


I have to experiment on this. Once I did and it was a failure.


Quote:
If client A is 20ft from the router with a SNR of 50, say dropping TX power reduced SNR to 45, both are still good but the max throughput may drop as well lets say 25Mbps becomes 21Mbps for ex.


So reducing the TX Power will reduce the internet speed also. Am I correct?

Quote:
"Strict DHCP" is setting max DHCP users to 0, therefor only static leases go out, even if you were to have wifi encryption off & SSID broadcast on & stranger connects, that user will not get a DHCP lease = no IP from router = no internet.

Yes, I have enabled it. It is good, thanks.
tatsuya46
DD-WRT Guru


Joined: 03 Jan 2010
Posts: 2323
Location: Winnipeg, Canada

PostPosted: Tue Feb 12, 2013 7:16    Post subject: Reply with quote
joscollin wrote:
So reducing the TX Power will reduce the internet speed also. Am I correct?


Only in a scenario when your line is faster than the max possible speed of your wifi, such as 802.11g maxing at about 26Mbps at absolute best, if you have a 30, 50Mbps etc line, wifi clients will never get that speed unless 802.11n is used.

_________________
[QUALCOMM ATHEROS] D-Link DIR-825 B1 -----------> DD-WRT v24-sp2 (12/15/14) std - build 25648
[QUALCOMM ATHEROS] TP-LINK TL-WDR4900 v1.3 --> DD-WRT v24-sp2 (12/22/14) std - build 25697 (private test)
[QUALCOMM ATHEROS] NETGEAR WNDR3700 v1 -----> DD-WRT v24-sp2 (12/22/14) std - build 25697 (private test)
[QUALCOMM ATHEROS] NETGEAR WNDR4300 v1 -----> DD-WRT v24-sp2 (12/22/14) std - build 25697 (private test)

LATEST FIRMWARE(S) --> ftp://ftp.dd-wrt.com/betas/
Qualcomm Atheros Wi-Fi Settings --> http://dd-wrt.com/wiki/index.php/QCA_wireless_settings
Qualcomm Atheros Client/Repeater Bridge --> http://dd-wrt.com/wiki/index.php/Repeater_Bridge#Qualcomm_Atheros

BrainSlayer wrote:
we just do it since we do not like any restrictions enforced by stupid cocaine snorting managers
joscollin
DD-WRT Novice


Joined: 12 Jan 2013
Posts: 10

PostPosted: Tue Feb 12, 2013 7:50    Post subject: Reply with quote
tatsuya46 wrote:
joscollin wrote:
So reducing the TX Power will reduce the internet speed also. Am I correct?


Only in a scenario when your line is faster than the max possible speed of your wifi, such as 802.11g maxing at about 26Mbps at absolute best, if you have a 30, 50Mbps etc line, wifi clients will never get that speed unless 802.11n is used.


I am using an internet connection of 4Mbps download speed. On the top of my Linksys WRT54G, it is written 2.4GHz and 54Mbps. Could you please suggest based on this information ?

THanks.
tatsuya46
DD-WRT Guru


Joined: 03 Jan 2010
Posts: 2323
Location: Winnipeg, Canada

PostPosted: Tue Feb 12, 2013 9:38    Post subject: Reply with quote
As you reduce TX power try to keep all clients' SNR at 12 minimum should be sufficient to get full 4Mbps throughput.
_________________
[QUALCOMM ATHEROS] D-Link DIR-825 B1 -----------> DD-WRT v24-sp2 (12/15/14) std - build 25648
[QUALCOMM ATHEROS] TP-LINK TL-WDR4900 v1.3 --> DD-WRT v24-sp2 (12/22/14) std - build 25697 (private test)
[QUALCOMM ATHEROS] NETGEAR WNDR3700 v1 -----> DD-WRT v24-sp2 (12/22/14) std - build 25697 (private test)
[QUALCOMM ATHEROS] NETGEAR WNDR4300 v1 -----> DD-WRT v24-sp2 (12/22/14) std - build 25697 (private test)

LATEST FIRMWARE(S) --> ftp://ftp.dd-wrt.com/betas/
Qualcomm Atheros Wi-Fi Settings --> http://dd-wrt.com/wiki/index.php/QCA_wireless_settings
Qualcomm Atheros Client/Repeater Bridge --> http://dd-wrt.com/wiki/index.php/Repeater_Bridge#Qualcomm_Atheros

BrainSlayer wrote:
we just do it since we do not like any restrictions enforced by stupid cocaine snorting managers
joscollin
DD-WRT Novice


Joined: 12 Jan 2013
Posts: 10

PostPosted: Thu Feb 14, 2013 5:38    Post subject: Reply with quote
Quote:
"Strict DHCP" is setting max DHCP users to 0, therefor only static leases go out, even if you were to have wifi encryption off & SSID broadcast on & stranger connects, that user will not get a DHCP lease = no IP from router = no internet.


The user will not be able to get an IP from the router. But he will be able to connect by assigning an IP statically and then access the internet.

I have set /etc/network/interfaces in my laptop as follows and it connects, even if I haven't assign a static lease for eth1.
iface eth1 inet static
address 192.168.1.100
netmask 255.255.255.0
gateway 192.168.1.2
tatsuya46
DD-WRT Guru


Joined: 03 Jan 2010
Posts: 2323
Location: Winnipeg, Canada

PostPosted: Thu Feb 14, 2013 7:15    Post subject: Reply with quote
Partly why you should move off the overused 192.168.x.x subnet and move to something in the 10.x.x.x subnet, they'll be guessing all day. Same as SSID broadcast off, they CAN guess it if they care to waste a long time, and cracking WPA2 AES taking even longer, and then MAC filtering.. stick all those together I don't think anyone is getting in unless they want to grow a beard 10 times over.
_________________
[QUALCOMM ATHEROS] D-Link DIR-825 B1 -----------> DD-WRT v24-sp2 (12/15/14) std - build 25648
[QUALCOMM ATHEROS] TP-LINK TL-WDR4900 v1.3 --> DD-WRT v24-sp2 (12/22/14) std - build 25697 (private test)
[QUALCOMM ATHEROS] NETGEAR WNDR3700 v1 -----> DD-WRT v24-sp2 (12/22/14) std - build 25697 (private test)
[QUALCOMM ATHEROS] NETGEAR WNDR4300 v1 -----> DD-WRT v24-sp2 (12/22/14) std - build 25697 (private test)

LATEST FIRMWARE(S) --> ftp://ftp.dd-wrt.com/betas/
Qualcomm Atheros Wi-Fi Settings --> http://dd-wrt.com/wiki/index.php/QCA_wireless_settings
Qualcomm Atheros Client/Repeater Bridge --> http://dd-wrt.com/wiki/index.php/Repeater_Bridge#Qualcomm_Atheros

BrainSlayer wrote:
we just do it since we do not like any restrictions enforced by stupid cocaine snorting managers
joscollin
DD-WRT Novice


Joined: 12 Jan 2013
Posts: 10

PostPosted: Thu Feb 14, 2013 8:07    Post subject: Reply with quote
tatsuya46 wrote:
Partly why you should move off the overused 192.168.x.x subnet and move to something in the 10.x.x.x subnet, they'll be guessing all day. Same as SSID broadcast off, they CAN guess it if they care to waste a long time, and cracking WPA2 AES taking even longer, and then MAC filtering.. stick all those together I don't think anyone is getting in unless they want to grow a beard 10 times over.


They don't have to guess at all. They can assign some IP to eth1 and use iwconfig to connect to the internet, provided SSID broadcast is enabled.

I checked with wired connections and static leases work perfectly with wired connections. (It is rejecting the IPs not listed inside the router.) But not with wireless.
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