Seeing same devices across multiple 245v3 EAP & transmit power optimization
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Hello all again,
I have finally hooked up my 2nd EAP 245 on my 2nd floor. I have a few questions with regards to power optimization and what I have been seeing so far:
1. What does Low, Medium and HIgh Tx power mean in dbm?
- Currently I have set both APs to low accross the 2.4 and 5 Ghz networks. The roaming seem to work a little bit better, but some devices still stick to the weaker AP.
2. I have been noticing that a few devices that roam, for instance my smartphone, is seen across both APs. Meaning, when I log in using the Omada app on my phone, I can see my phone logged in to both EAPs under "Devices". Is this normal? Should I reduce the transmition power even more, lower than what "Low" is?
P.S I am interested in turning an old laptop into a plex server, which I will also use as a Software Controller, so hopefully my #2 issue will go away since the fast roaming will be enabled (if that is the issue).
Any thoughts or opinions?
Thank you in advance,
EDIT: The duplicate device eventually does disappear on the weaker AP, just seems to take a bit of time. But the devices that 'stick' to the weaker signal AP that don't roam, seems to only switch to the stronger signal AP if I disconnect/connect them back to the network.
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Jmusic88 wrote
What do you mean by removing 3dbm, I am cutting the signal in half? I originally had my first AP on high, but when I changed it to low, I was still getting a pretty decent signal throughout the house, but I just did not want it to overpower my AP on my 2nd floor which is why I have everything set to low now, that is 14 dBm difference, which means way more than half.
dBm is a dimensionless unit used for expressing wireless signal strength, see https://en.wikipedia.org/wiki/DBm for an explanation.
Usually, signal power is reduced if there are too many interferences, e.g. if the EAPs are closer to each other than ~15m.
14dBm difference is not more than half, but factor 25. 24 dBm equals 250 mW TX power, 10 dBm equals 10mW. That's very low and might decrease throughput and reliability against interferences if too low. I recommend to set it to »High« or to 20 dBm (100 mW) unless there are massive interferences with other APs, then I would decrease it in steps of 1 dBm until interferences disappear.
You can't overpower EAPs if you follow the rule to use different channels for different EAPs. If in doubt, don't worry too much. Just use reasonable default settings (»High« TX power).
Regarding the duplicate devices - when you say the Omada controller? Are you talking about the imbedded controller/default operation of the EAPs? Since I am currently only using the web-based omada login, or the android omada app. I am not running no other controllers (software or OC-200).
I was referring to the controller software, not the web UI of the EAPs. The EAPs send statistics data to the controller in intervals, that's why there is a delay of the real state and the state shown in Omada controller (few minutes until the next update).
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Hi Jmusic88,
1. You can find out as follows: select »Medium« or »Low«, apply and then select »Custom« to see the last value.
For my EAP225-Outdoor »Low« is 8dBm, »Medium« is 14 dBm and »High« is 20dBm.
Better use »Custom« if you change intend to change Tx power, keep in mind that a reduction of 3dBm cuts power by half.
2. Omada controller needs a few minutes to remove disconnected clients, it's protocol-specific.
AFAIK, »Fast Roaming« does not change this behavior.
PS: A laptop is no recommended platform for Omada controller, since laptops usually go into hibernation mode when idle for a few minutes. Better use a server which runs 24x7 if you plan to use »Fast Roaming«.
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Thanks again for your reply!
It looks like for my EAP 245 v3 the transmit power is as follows: Low is 10, Medium is 17 and high is 24. Would you have any recommendations on what they should ? I understand that different layouts, material, size of houses will make the difference but maybe there is some sort of a "rule"? Or what should I be looking for so I will know if the set tx power is good. Currently, everything is set to low (both 2.4 and 5 Ghz networks), can it be too low? It seem to be fine-ish, of course this is only after a few hours of use. I will monitor in the next few days if I have to adjust.
What do you mean by removing 3dbm, I am cutting the signal in half? I originally had my first AP on high, but when I changed it to low, I was still getting a pretty decent signal throughout the house, but I just did not want it to overpower my AP on my 2nd floor which is why I have everything set to low now, that is 14 dBm difference, which means way more than half.
Regarding the duplicate devices - when you say the Omada controller? Are you talking about the imbedded controller/default operation of the EAPs? Since I am currently only using the web-based omada login, or the android omada app. I am not running no other controllers (software or OC-200).
In regards to the laptop running the software controller - I will be re-purposing an old laptop as a server. I will not have sleep or hiberation set up. It will be running 24/7. I intend to use it as a plex server mainly, but since the Software Omada Controller seems to be pretty small, I will install that as well.
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Jmusic88 wrote
What do you mean by removing 3dbm, I am cutting the signal in half? I originally had my first AP on high, but when I changed it to low, I was still getting a pretty decent signal throughout the house, but I just did not want it to overpower my AP on my 2nd floor which is why I have everything set to low now, that is 14 dBm difference, which means way more than half.
dBm is a dimensionless unit used for expressing wireless signal strength, see https://en.wikipedia.org/wiki/DBm for an explanation.
Usually, signal power is reduced if there are too many interferences, e.g. if the EAPs are closer to each other than ~15m.
14dBm difference is not more than half, but factor 25. 24 dBm equals 250 mW TX power, 10 dBm equals 10mW. That's very low and might decrease throughput and reliability against interferences if too low. I recommend to set it to »High« or to 20 dBm (100 mW) unless there are massive interferences with other APs, then I would decrease it in steps of 1 dBm until interferences disappear.
You can't overpower EAPs if you follow the rule to use different channels for different EAPs. If in doubt, don't worry too much. Just use reasonable default settings (»High« TX power).
Regarding the duplicate devices - when you say the Omada controller? Are you talking about the imbedded controller/default operation of the EAPs? Since I am currently only using the web-based omada login, or the android omada app. I am not running no other controllers (software or OC-200).
I was referring to the controller software, not the web UI of the EAPs. The EAPs send statistics data to the controller in intervals, that's why there is a delay of the real state and the state shown in Omada controller (few minutes until the next update).
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R1D2 wrote
dBm is a dimensionless unit used for expressing wireless signal strength, see https://en.wikipedia.org/wiki/DBm for an explanation.
Usually, signal power is reduced if there are too many interferences, e.g. if the EAPs are closer to each other than ~15m.
14dBm difference is not more than half, but factor 25. 24 dBm equals 250 mW TX power, 10 dBm equals 10mW. That's very low and might decrease throughput and reliability against interferences if too low. I recommend to set it to »High« or to 20 dBm (100 mW) unless there are massive interferences with other APs, then I would decrease it in steps of 1 dBm until interferences disappear.
You can't overpower EAPs if you follow the rule to use different channels for different EAPs. If in doubt, don't worry too much. Just use reasonable default settings (»High« TX power).
Do you recommend to set both 2.4ghz and 5ghz to high? I have read that the 2.4 ghz signal should be weaker than the 5 ghz just because it's a stronger/farther signal to begin with.
I originally had both of them set to high, but both APs can cover the whole house decently, so the closer devices would catch the farthest AP and vice versa. Also any roaming devices, wouldn't roam because it would stick to the original AP. If I install the software controller and set the fast roaming, would it roam better even if both APs are on high Tx?
Also how would I know if I get interference? I have set both of my APs to operate in different channels (both 2.4 ghz and 5 ghz). My neighbourhood isn't full of networks either. 5 ghz is pretty empty, I only see myself and my closest neighbour mostly but their signal is weak so it doesn't always show up on the channel graph. The 2.4 networks are of course a little busier, but their signal is weaker, I tried to use the channels with less interference. Channel 1 and 6 are the ones that most don't overlap my neighbours signals. Channel 11 is the busiest and a few on channel 8-9 with 40 mhz so I just avoid 11, although it over laps on 6, I just can't avoid it but signal is weak so it doesn't always show up.
Thanks again
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Jmusic88 wrote
Do you recommend to set both 2.4ghz and 5ghz to high? I have read that the 2.4 ghz signal should be weaker than the 5 ghz just because it's a stronger/farther signal to begin with.
»High« is the maximum and the maximum for 2.4 GHz is already 4dBm lower than that for 5 GHz.
I originally had both of them set to high, but both APs can cover the whole house decently, so the closer devices would catch the farthest AP and vice versa. Also any roaming devices, wouldn't roam because it would stick to the original AP. If I install the software controller and set the fast roaming, would it roam better even if both APs are on high Tx?
Roaming depends on the client device's decision to change the AP. If the device doesn't roam, it means that the signal of the AP the device is currently connected to is strong enough, so roaming won't make a big difference. Probably two EAPs are just oversized for your house. Better than roaming is a strong signal of one EAP in the whole are which should be covered. Fast roaming can force a client to roam, but still the client device will decide to which AP it connects to. The controller can't do anything in regard to this roaming decision, except to instruct the device to roam. But whether it does, is the device's decision.
Also how would I know if I get interference?
Either by detecting bad throughput, flaky connections, frequent flips between APs etc. or by doing professional measurements using a WiFi heat mapper such as NetSpot. Note that interferences appear with an increasing load such as the load common in overcrowded areas. If you don't notice bad throughput or other malfunctions, don't worry about Tx signal levels.
The 5 GHz band appears to be empty b/c 5 GHz signals are more attenuated by obstacles than 2.4 GHz signals. So, you don't »see« that many foreign 5 GHz APs, albeit they might be there.
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Thank you. I'll see increase my APs to medium and see how they perform. Maybe the way my house is, two EAPs are just oversized as you said. When you say the high on the 2.4ghz is already 4dbm lower, where do you see that? Based on my EAP, looking at the custom method, the value is the same whether it is 2.4 or 5ghz.
Too bad, I guess I feel like I wasted money on an additional EAP thinking it will improve my signal. Don't get me wrong though, having it on low makes majority of my devices on the green side (-40 to - 60 dbm) where before I had a few on the - 70 range.
My second EAP is in my office room which covers a decent portion of my second floor. Worse case, I'll have my main floor EAP cover my whole house (set to high) and have my second EAP concentrated on my office devices as they were getting weak 5Ghz wifi signal. So it'll still be used. But looking back, I would of been ok with EAP225 on my second floor instead of the 245. At least I got it on sale lol.
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Jmusic88 wrote
When you say the high on the 2.4ghz is already 4dbm lower, where do you see that?
Because the law dictates maximum TX power allowed in each band. In my country it's 20dBm = 100mW for 2.4 GHz, 23dBm = 200mW for the 5 GHz indoor-only channels and up to 30dBm = 1,000mW for 5 GHz outdoor channels.
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R1D2 wrote
Because the law dictates maximum TX power allowed in each band. In my country it's 20dBm = 100mW for 2.4 GHz, 23dBm = 200mW for the 5 GHz indoor-only channels and up to 30dBm = 1,000mW for 5 GHz outdoor channels.
I live in Canada but we use the US EAP version (the ones I bought states US on the serial tag). Looking up the laws in Canada, I can see clearly a chart for the 5Ghz online, not so much for the 2.4ghz. But it looks like the 2.4 is the same as you, the 5ghz ranges from 200 mw (indoor) , 250mw to 1000mW (indoor & outdoor) depending on the channel.
But my EAP allows 24dbm (250mw) for both 2.4ghz and 5ghz. So when I had it set to high thats what it was set to.
Im assuming it's not set automatically then and I should be setting it manually that way?
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5 GHz in Canada is a mix of U.S. and EU regulations:
- Channels in the U-NII-1 band (ch 32 to 48) are allowed indoors only, much like in the EU.
- Channels in the U-NII-2A (ch 50 to 68), U-NII-2C (ch 100 to 144) and U-NII-3 (ch 149 to 165) are allowed indoors and outdoors. Their use requires either DFS/TPC for 1,000mW EIRP or are limited to 500mW EIRP if they don't support DFS/TPC.
AFAIK, EAP225 US version does not support DFS/TPC channels, while the EU version does so (b/c in the EU only the U-NII-2C band is allowed outdoors).
For 2.4 GHz i didn't found an official specification for Canada.
If you manage to find the correct values (your government website could have information about RLAN regulatory provisions), you might set those as custom values.
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