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Technical Inquiry: Frequent DFS Radar Detection Alerts – Omada SDN – [Varga Tanya Park Hotel]

Technical Inquiry: Frequent DFS Radar Detection Alerts – Omada SDN – [Varga Tanya Park Hotel]

Technical Inquiry: Frequent DFS Radar Detection Alerts – Omada SDN – [Varga Tanya Park Hotel]
Technical Inquiry: Frequent DFS Radar Detection Alerts – Omada SDN – [Varga Tanya Park Hotel]
Thursday - last edited Friday
Tags: #Health
Model: EAP653   EAP650-Outdoor  
Hardware Version: V1
Firmware Version: 1.3.3,

Dear TP-Link Support Team,

My name is József Tóth, and I am the System Administrator for a hotel complex located in a rural area, Hungary. I am writing to request technical assistance or an explanation regarding a persistent issue with our wireless network.

Site Environment:

  • Infrastructure: 38 TP-Link Omada Access Points (mixed indoor and outdoor models) managed via an Omada Controller (Firmware Version: 1.32.10 Build 20260117 Rel.84796).
  • History: The system has been operating stably for over a year.
  • Problem: For the past month, we have been receiving frequent "Radar detected" alerts on DFS channels. This issue currently affects nearly all 38 APs.

No changes have been made to our internal environment or network configuration prior to these alerts starting. I have attached a table listing the affected devices and the specific channels where the detections occurred.

Could you please provide insights into why these detections might have started suddenly after a year of stability? Additionally, are there any recommended controller settings or firmware tweaks to mitigate these frequent channel shifts without compromising performance?

I look forward to your professional advice.

Best regards,

József Tóth System Administrator

File:
DeviceList_2026-03-11-17-34-pre.xlsxDownload
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Re:Technical Inquiry: Frequent DFS Radar Detection Alerts – Omada SDN – [Varga Tanya Park Hotel]-Solution
Friday - last edited Friday

Hi  @TJoe 

 

Thanks for posting here.

 

Firstly, you may have a look at the following document to understand DFS function: 

Brief introduction of DFS function

 

 

Most Likely Cause: The Installation of New Radar Facilities Nearby 

The DFS (Dynamic Frequency Selection) mechanism (primarily in the W52/W53/W56 channels of the 5GHz band) requires wireless devices to immediately vacate a channel if they detect signals from primary systems such as weather radar or military radar. In rural areas, the deployment or testing of new radar facilities (even temporary or mobile ones) is the most common cause of such issues. Even if your equipment remains unchanged, alterations in the external RF environment can trigger this mechanism.

 

 

  1. Temporarily Avoid DFS Channels (Temporary Solution):

    • Manually fix the channels to non-DFS channels (36-48) for the EAPs.
    • Drawback: This significantly reduces the number of available channels, which may increase co-channel interference in high-density AP deployments and impact overall performance. It is acceptable as a temporary measure.

  2. Adjust Transmission Power:

    • Try slightly reducing the transmission power of APs in areas most affected by DFS alerts. Sometimes, lowering the power can reduce the likelihood of APs detecting faint radar signals from a distance, thereby preventing unnecessary channel changes while maintaining coverage quality.

 

If the use of DFS channels is necessary to gain more channels and higher performance, a strategic deployment approach can be adopted: Configure only indoor APs located in the central, well-shielded areas of the building to use DFS channels, while mandatorily setting all outdoor APs and indoor APs near the periphery or windows to operate on non-DFS channels. This strategy can significantly reduce the probability of triggering channel changes due to the detection of external radar signals.

Wish you a happy life and smooth network usage!  >Omada US Enterprise Beta Program Launch< >Get the Latest Omada SDN Controller Releases Here< >Experience the Latest Omada EAP Firmware<
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Re:Technical Inquiry: Frequent DFS Radar Detection Alerts – Omada SDN – [Varga Tanya Park Hotel]-Solution
Friday - last edited Friday

Hi  @TJoe 

 

Thanks for posting here.

 

Firstly, you may have a look at the following document to understand DFS function: 

Brief introduction of DFS function

 

 

Most Likely Cause: The Installation of New Radar Facilities Nearby 

The DFS (Dynamic Frequency Selection) mechanism (primarily in the W52/W53/W56 channels of the 5GHz band) requires wireless devices to immediately vacate a channel if they detect signals from primary systems such as weather radar or military radar. In rural areas, the deployment or testing of new radar facilities (even temporary or mobile ones) is the most common cause of such issues. Even if your equipment remains unchanged, alterations in the external RF environment can trigger this mechanism.

 

 

  1. Temporarily Avoid DFS Channels (Temporary Solution):

    • Manually fix the channels to non-DFS channels (36-48) for the EAPs.
    • Drawback: This significantly reduces the number of available channels, which may increase co-channel interference in high-density AP deployments and impact overall performance. It is acceptable as a temporary measure.

  2. Adjust Transmission Power:

    • Try slightly reducing the transmission power of APs in areas most affected by DFS alerts. Sometimes, lowering the power can reduce the likelihood of APs detecting faint radar signals from a distance, thereby preventing unnecessary channel changes while maintaining coverage quality.

 

If the use of DFS channels is necessary to gain more channels and higher performance, a strategic deployment approach can be adopted: Configure only indoor APs located in the central, well-shielded areas of the building to use DFS channels, while mandatorily setting all outdoor APs and indoor APs near the periphery or windows to operate on non-DFS channels. This strategy can significantly reduce the probability of triggering channel changes due to the detection of external radar signals.

Wish you a happy life and smooth network usage!  >Omada US Enterprise Beta Program Launch< >Get the Latest Omada SDN Controller Releases Here< >Experience the Latest Omada EAP Firmware<
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Re:Technical Inquiry: Frequent DFS Radar Detection Alerts – Omada SDN – [Varga Tanya Park Hotel]
Friday

Hi Vincent,
Thanks for the instructions!
I will do the setup and share my experience in a few days.

 

Thanks
TJoe 

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Re:Technical Inquiry: Frequent DFS Radar Detection Alerts – Omada SDN – [Varga Tanya Park Hotel]
Friday - last edited Friday

  @TJoe 

 

My building is very close to a marina, fishing and shipping port and yacht berths, i see this frequently.

 

Unfortuantely there isnt a whole lot more than what Vincent said - DFS detection and channel hopping is something that is mandatory in access points in most parts of the world, and jsut because this never used to happen doesnt mean that there isnt a new Radar somewhere that is now triggering this

 

For the most part, unless it causes actual client interruptions, and you need to use the DFS channels to reduce overlap between APs, there isnt much you can do other than some power level tweaks.  If the radar signal being detect is strong, it will happen regardless.

 

Another approach is to reduce 5ghz to 20mhz bandwidth, and start putting access points on different 36-48 channels across the site, but this will reduce throughput significantly (for guest wifi probbaly not much of an issue though)

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