---
name: "athctrl"
section: "8"
platform: "linux"
package: "madwifi-tools"
version: "1:0.9.4+r3685.20080531+dfsg-1"
release: "Debian 5.0 (Lenny)"
platforms: ["linux"]
url: "https://new.carta.tech/athctrl"
---

# athctrl(8)

sets the maximum distance between communicating stations

## NAME

**athctrl** - sets the maximum distance between communicating stations

## SYNOPSIS

**athctrl** \[-h\] \[-i device\] \[-d distance\]

## DESCRIPTION

**athctrl** sets the maximum distance in meters of stations with which  communication occurs. This distance metric determines how much time the radio waits for an acknowledgment after every transmission and it sets a few other  derived timing parameters. This limits the distance between two stations at  which the collision avoidance, acknowledgment, retransmission protocols will  work correctly.

In particular, when transmitting to too distant stations the radio will start  retransmitting packets before an ACK can possibly have been received causing  unnecessary retransmissions and collisions. The distance parameter needs to be  set properly on all stations that perform long-distance communication  irrespective of their mode of operation (master/managed/ad-hoc). For best  operation all stations communicating with each other should be set to the same value.

## OPTIONS

- **-i device**

  The madwifi device to apply the settings to. If no device is specified, **athctrl** defaults to wifi0.

- **-d distance**

  Distance in metric meters.

- **-h**

  Display usage.

## EXAMPLES

- **athctrl -i wifi1 -d 500**

  Set maximum distance of 500m for wifi1.

- **athctrl 1000**

  Set maximum distance of 1000m for wifi0.

## SEE ALSO

[**athchans**(8)](/athchans/8.md), [**athkey**(8)](/athkey/8.md), [**athstats**(8)](/athstats/8.md)

## AUTHOR

This manual page was written by Kel Modderman \<kelrin@tpg.com.au\> and was based upon previous text written by Eric S. Raymond and Thorsten von Eicken.