Re: Is it possible to decrease the Transmission power in D-link DWL 650 with hostap installed on linux

From: Jouni Malinen (
Date: 2002-06-19 16:29:36 UTC

On Wed, Jun 19, 2002 at 07:04:12PM +0530, Manjunathan PY wrote:

> I want to know if one can decrease the transmission power of D-Link DWL
> 650 PCMCIA card
> on linux.

Assuming you are using Host AP driver, yes it is possible. 'iwconfig wlan0 txpower <val>' can be used to set TX power. <val> is value in dBm. However, it might not be that close to the real power level, but it should be monotone increasing. I have used -43 dBm as the minimum and +20 dBm as the maximum. Anything below -43 is equal to -43 and likewise with +20. E.g., 'iwconfig wlan0 txpower -43' will set the minimum power (and 'iwconfig wlan0 txpower auto' returns the TX control to station firmware).

> What is the minimum power that is used here!

This depends on the used card model and antenna. I did some measurements a while ago with D-Link DWL-650 and another card saw a decrease of about 30 dBm when changing the txpower setting from maximum to minimum (Compaq WL100 allowed even more, about 50 dBm decrease). Anyway, at the minimum TX power setting the range of the card is quite limited; maybe a meter or so with 11 Mbps.

Jouni Malinen                                            PGP id EFC895FA

This archive was generated by hypermail 2.1.4.