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Cisco Aironet 1240AG, Autonomous, without the external antennae

Hi there,

I have the below confusions/questions about the Cisco Aironet 1240AG:

  • What is the wireless range of this access-point when there is no external antennae attached - fresh out of the box?
  • We have this AP (withoiut the external antennae) in our office. We use the RADIUS authentication for wireless access (Microsoft IAS). Whenever the laptop (windows XP) is not connected (it is trying to associate and get authentication from RADIUS) the signal strength is 'ALL BARS - Excellent' at 4-5 meters from the AP - but as soon as the laptop is authenticated and the wirelss is connected, the signal strength comes down to '2 BARS - Low/very-low'. It drops significantly after the laptop is connected to the wirelss. Do you see any possible reason behind it?

It is small conf room with 12X12 sq feet measurement and at the corner it shows 'very low' signal strength


Re: Cisco Aironet 1240AG, Autonomous, without the external anten


You cannot/should not use these APs without antennas. There are two main reasons:

1. Without an antenna, the electrical energy emitted by the radio is not converted to RF energy. This explains why you see very low signal. If you are seeing good signal at any point, you are probably just seeing random flares off the connector itself, but the 4-5 bars is not indicative of what you're actually going to get.

2. If you don't transfer the energy out through an antenna, it instead leaks from the radio in the form of heat energy. This heat will eventually burn out your radio and kill the AP.

Recommendation: Put at least one antenna per radio on the 1240, although it works better with two (Diversity). For each pair of rptnc connectors, you will see one marked Primary. Use that one.


Sent from Cisco Technical Support iPhone App

New Member

Re: Cisco Aironet 1240AG, Autonomous, without the external anten

Thanks Justin.. Looking forward to learn more from the guys like you

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