topic Re: Cisco 3802i-E increase power level (dBm) on 9800-CL Controller in Wireless

Cisco 3802i-E increase power level (dBm) on 9800-CL Controller

Matthias28 — Mon, 05 Jul 2021 20:13:38 GMT

Hello,

I have two Cisco 3802i-E Access Points were I need a higher power level on the 2.4 GHz WiFi that I will get a stronger singal, because I want to build a Mesh between them because I am not able to setup a cable on the other site.

According to the Cisco 9800CL Controller the highest power level is with 14 dBm on Power Level 1.

On the Cisco Website on the product page it is written, that they are able to get 23 dBm (200 mW) on 24.GHz.

Is there a setting to increase the power levels or is there a reason why, the highest power level only has 14 dBm?

On the Cisco 9800 CL Controller I use the Firmware 17.3.3 and the country on the AP's are set to DE.

Thanks for your help in advance.

Greetings

Matthias28

Re: Cisco 3802i-E increase power level (dBm) on 9800-CL Controller

Rasika Nayanajith — Mon, 26 Apr 2021 20:02:57 GMT

"According to the Cisco 9800CL Controller the highest power level is with 14 dBm on Power Level 1."

You have to check whether you limit TPC min/max value under Configuration -> Radio Configuration -> RRM -> TPC (in 2.4GHz & 5GHz) or under Configurations -> Tags & Profile -> RF -> "select your RF profile for these APs" ->RRM -> TPC

May be you set max value to 14dBm

HTH

Rasika

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Re: Cisco 3802i-E increase power level (dBm) on 9800-CL Controller

Matthias28 — Mon, 26 Apr 2021 20:27:15 GMT

Thanks for your response.

I have now created a new RF Profile and assigned it to the Default RF Profile and on Configuration -> Radio Configuration -> RRM I have set the Power Assignment Method to Fixed 1 with Max Power Level Assignment 30.

I have also rebooted the APs but I still not get more than 14 dBm. I have also added screenshots of it.

Thanks.

Re: Cisco 3802i-E increase power level (dBm) on 9800-CL Controller

Rasika Nayanajith — Mon, 26 Apr 2021 20:38:41 GMT

RRM may take time to adapt.

If you need, you can go directly to AP (Configuration -> Wireless -> Access Point -> 2.4/5.0 Radio and statically set the power level on each AP radio

HTH

Rasika

Re: Cisco 3802i-E increase power level (dBm) on 9800-CL Controller

Scott Fella — Tue, 27 Apr 2021 05:11:50 GMT

It does show that your TX is limited to 14dbm. That is co trolled by the country code. 23dbm is typically with outdoor AP’s as you will not be able to achieve.

Re: Cisco 3802i-E increase power level (dBm) on 9800-CL Controller

Matthias28 — Tue, 27 Apr 2021 14:45:30 GMT

Thanks for your reply. As far as I know is the maximum dBm level for Germany 20 dBm. Is there a way to achive that instead of the 14 dBm to which it is currently limited or maybe can it help to change it to another country for test which has also E as regulatory domain?

Thank you.

Re: Cisco 3802i-E increase power level (dBm) on 9800-CL Controller

Matthias28 — Tue, 27 Apr 2021 14:47:45 GMT

I have already set that the Power Level 1 is used, which give me only 14dBm in this case.

Thanks.

Re: Cisco 3802i-E increase power level (dBm) on 9800-CL Controller

patoberli — Tue, 27 Apr 2021 15:00:47 GMT

Germany allows a maximum of 100 mW of output power, which corresponds to 20 dBm. https://de.wikipedia.org/wiki/Sendeleistung

Please note, that includes the antenna gain! Which is on the 3802i an additional 4 dBi on 2.4 GHz.

https://www.cisco.com/c/en/us/products/collateral/wireless/aironet-3800-series-access-points/datasheet-c78-741682.html

And I think this causes it to be limited to those 14 dBm. Some numbers are shown without the gain, while others are with.

Re: Cisco 3802i-E increase power level (dBm) on 9800-CL Controller

Matthias28 — Tue, 27 Apr 2021 16:16:37 GMT

Thanks. That I understand it correctly, this means that the 20dBm already includes the antenna gain and the Controller shows the 14 dBm without the antenna gain?

My main issue is, that I want to replace two AP's from another company which has no issue to connect each other via Mesh.

When I do the same with the Cisco AP's which are on the same place as the other AP's the Mesh AP only sometimes gets a connection for some seconds and then it looses again the connection to the Root AP and tries to reconnect again without success. I switched also to 2.4 GHz on the Mesh AP's.

Is there maybe anything else which I can do?

Thanks.

Re: Cisco 3802i-E increase power level (dBm) on 9800-CL Controller

patoberli — Tue, 27 Apr 2021 16:33:50 GMT

You might want to use a different model maybe with external antennas. Also the radiation pattern between the two AP models might be very different.

Re: Cisco 3802i-E increase power level (dBm) on 9800-CL Controller

Matthias28 — Tue, 27 Apr 2021 17:40:34 GMT

OK I will check if I can get the access points with external antennas or maybe place the current Root AP to a other place were maybe the signal is a little bit better.

I also noticed when I used my mobile phone at this place were the Mesh AP should be located, my mobile phone sees the 2.4Ghz WiFi and can also connect to it and for my understanding the Mesh AP should then also be able to get a connection to the Root AP or not?

Re: Cisco 3802i-E increase power level (dBm) on 9800-CL Controller

JPavonM — Wed, 28 Apr 2021 05:55:37 GMT

@Matthias28 regulations mark the maximum EIRP a device can transmit which means [AP TX Power level] + [Antenna Gain].

Additionally, setting the TX power level manually on the AP is not TPC compliant, so reducing additional 3 dB from maximum allowed in ETSI domain (https://wlan1nde.wordpress.com/2014/11/26/wlan-maximum-transmission-power-etsi/)

In your case, the TX power level is 14 dBm, add 6 dBi from the internal antenna in 5 GHz radio interface an you have it.

My advice, leave TPC decide the TX power level, and limit this level to half the maximum TX power level of the least capable device (normally smartphones) to avoid power impairment and battery drain.

HTH
-Jesus
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Re: Cisco 3802i-E increase power level (dBm) on 9800-CL Controller

patoberli — Wed, 28 Apr 2021 06:51:15 GMT

It should, yes. I've never used Mesh with Cisco though, so I lack some experience there.
Does it work if the two APs are closer to each other?

Re: Cisco 3802i-E increase power level (dBm) on 9800-CL Controller

JPavonM — Wed, 28 Apr 2021 07:05:18 GMT

Normally in all vendors, 5 GHz band use to be used for backhaul connection, and 2.4 GHz band for client connection, so you device connecting in 2.4GHz to the mesh AP doesn't mean the AP is able to see the root AP in 5 GHz.

Check your config.

Re: Cisco 3802i-E increase power level (dBm) on 9800-CL Controller

Matthias28 — Wed, 28 Apr 2021 15:37:06 GMT

I have tested the connection when both APs are standing next to each other. Then the Mesh connection is working without issue.

Re: Cisco 3802i-E increase power level (dBm) on 9800-CL Controller

Matthias28 — Wed, 28 Apr 2021 15:40:23 GMT

The 5GHz signal is very weak at this place were the Mesh AP is placed. The 2.4GHz signal is able to get there.

In the Mesh Settings I have changed the Backhaul Radio Type to 2.4GHz, so I think this should use the 2.4GHz instead of the 5GHz.

The Aruba iAP APs which I have currently have no issues to connect to each other at the same place and they also have only internal antennas.

Re: Cisco 3802i-E increase power level (dBm) on 9800-CL Controller

patoberli — Thu, 29 Apr 2021 06:46:42 GMT

I don't know this AP model exactly, but I do know that the Cisco xxxxi models (with internal antennas) are more optimized for dense indoor networks and less for long distance mesh ones. For that they have their own mesh AP series, I think even with some additional software features. I never deployed a mesh, so I'm not 100% sure about the software.

For mesh on the C9800, I found this fairly short guide here:

https://www.cisco.com/c/en/us/support/docs/wireless/catalyst-9800-series-wireless-controllers/215100-join-mesh-aps-to-catalyst-9800-wireless.html

And this very extensive one:

https://www.cisco.com/c/dam/en/us/td/docs/wireless/controller/9800/17-1/deployment-guide/c9800-mesh-rel-17-1.pdf

I think the chapter Monitoring might be very useful here.