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Regular Member
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Registered: ‎11-19-2008
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DFS VS NON DFS

hello frds...

 

could someone explain the difference between DFS channel and Non DFS channel in regards to throughput, performance, advantage and disadvantge. what is the purpose of calling and putting certain channels as DFS channels.

 

Kind Regards.

SuperUser
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Re: DFS VS NON DFS

A quick Google search found these:

 

http://wifi-insider.com/wlan/dfs.htm

 

https://www.networkcomputing.com/wireless/dynamic-frequency-selection-why-its-critical-80211ac/14394...

 

In practical terms, a radio that intends to transmit

on a DFS channel must listen on the channel for

a minimum time period to determine if a radar

signal is present. If so, it must not transmit; it

can continue to test. If other channels are

available, the radio proceeds to the next one.

 

A radio must also re-test at intervals and cease

transmission if it finds radar activity.

 

So don't expect a DFS channel to link up quickly--

as non-DFS channels will; there's always a delay.

And of course if there's DFS activity, the channel

will be unavailable. But once a channel is linked,

it is as useful as any other in the band.

 

In practice, you should check for the kind of doppler

wind-shear radar in use at airports within your

vicinity and avoid their use. In Europe, many or

most channels may be 'DFS', but that doesn't

indicate that DFS is actually in use in your area.   Dave


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Ubiquiti Employee
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Re: DFS VS NON DFS

To follow on from Dave's post, there is no real throughput difference in the way you may be thinking. In non-DFS channels, you are able to transmit as you please within legal limits, and other users cannot prevent you from doing so. DFS channels however are home to both you and other unlicensed users, as well as higher-priority users such as weather radars. When these higher-priority users need to use the channel, your radio will be forced to change channel.