Hi @Carl, I've not tested the 5.0 GHz band to be honest. When I separated the two bands with unique SSIDs, I didn't even bother mentioning this to my aunt. She is in her 70s and it is just easier for me to leave her on the 2.4GHz. I liked the idea of the devices being able to switch between the bands, but I was thinking it may have been causing the issue if the devices were getting stuck between switching from one band to the other. I can't confirm what channel the 2.4GHz is on right now. I know that I either changed it to 11 or 6. I'm leaning towards 6 because I think it was the least populated channel. She lives in a mobile park for seniors and it seems like they're all broadcasting wi-fi. I chose the least congested looking channel. For 5.0GHz I definitely picked one of the higher channels. I believe I actually set 149. I will have to confirm at a later date. I thought I had configured remote management access, but apparently I didn't do it right. I may be able to head back to her house later this week and confirm the settings along with grabbing the logs.  

  @BenGr 

It would appear to be a 'phone' issue possibly...

I say that because phones move and TV's do not? Also, there could be a lot of 'metal' in the walls of a mobile home... or even stronger interference in some areas. If you can, run the Network Analyzer where the connection tends to drop.

Also check with NO SECURITY to see if ti works that way on the phones. Also turn off PRIVATE WIFI ADDRESS on the iPhones, see if that helps.

I'd put all the phones on the 5Ghz SSID, as they will reach further than the 2,4Ghz SSID which tends to lose signal power sooner.,

  @IrvSp I do agree that it appears to be phone related as of now. No similarity between phone models as I have seen this happening with two different model iPhones and two different model Androids. I did run an Ethernet cable underneath her flooring. I did find the studs are all wood, but there definitely is some metal beams in the flooring. I don't think that would cause any issues though. Additionally, I think you have your bands confused. 2.4 GHz definitely has better range, but does not perform as well as 5.0 GHz when it is in range with a good signal. The larger frequency of the 5.0 GHz doesn't give it the range that 2.4 GHz has. I'm planning on going back to her house on Thursday or Friday for one last ditch effort. I'm going to be viewing the logs for any clues. I plan on flashing OpenWRT at some point as a last resort. I've already ordered a replacement router set to be here on Monday. I'm really surprised with the performance as I have this same router in my house and I bought and installed one for my Dad who also happens to live in a senior mobile home park. 

  @BenGr 

Sorry, you are right, 2.4Ghz goes further than 5Ghz but it decays faster. 5Ghz provides at distance a stronger signal usually, but does drop off faster.

You didn't mention the distance when the phones drop, away from the router out of line of sight, or right next to the router.

Might even need a repeater using the power line type if it isn't the router and another one does the same thing? Might want to bring your router to there and see?

We've got both an iPhone (and some iPad's) as well as an Android phone. The Android is less reliable the further away from the router.... and my iPad Pro is better than my wife's older iPad Pro (2018 vs. 2016 models). I suspect the chipset antennae being used in them.