我剛買了一個新路由器，它很貴（華碩 RT-AC66U）。我很快就意識到，2.4GHz 和 5GHz 上的無線連線都非常糟糕。 Mac 或 PC 的結果類似。典型的 ping 會話如下所示（超過 2 分鐘，間隔 1 秒）：
PING 192.168.1.1 (192.168.1.1): 56 data bytes
64 bytes from 192.168.1.1: icmp_seq=0 ttl=64 time=2.190 ms
64 bytes from 192.168.1.1: icmp_seq=1 ttl=64 time=3.985 ms
64 bytes from 192.168.1.1: icmp_seq=2 ttl=64 time=4.155 ms
64 bytes from 192.168.1.1: icmp_seq=3 ttl=64 time=1.375 ms
64 bytes from 192.168.1.1: icmp_seq=4 ttl=64 time=1.541 ms
64 bytes from 192.168.1.1: icmp_seq=5 ttl=64 time=8.862 ms
64 bytes from 192.168.1.1: icmp_seq=6 ttl=64 time=12.327 ms
64 bytes from 192.168.1.1: icmp_seq=7 ttl=64 time=13.154 ms
64 bytes from 192.168.1.1: icmp_seq=8 ttl=64 time=4.244 ms
64 bytes from 192.168.1.1: icmp_seq=9 ttl=64 time=284.630 ms
64 bytes from 192.168.1.1: icmp_seq=10 ttl=64 time=301.342 ms
64 bytes from 192.168.1.1: icmp_seq=11 ttl=64 time=328.569 ms
64 bytes from 192.168.1.1: icmp_seq=12 ttl=64 time=10.168 ms
64 bytes from 192.168.1.1: icmp_seq=13 ttl=64 time=4.230 ms
64 bytes from 192.168.1.1: icmp_seq=14 ttl=64 time=1.207 ms
64 bytes from 192.168.1.1: icmp_seq=15 ttl=64 time=19.310 ms
64 bytes from 192.168.1.1: icmp_seq=16 ttl=64 time=4.040 ms
64 bytes from 192.168.1.1: icmp_seq=17 ttl=64 time=4.059 ms
64 bytes from 192.168.1.1: icmp_seq=18 ttl=64 time=4.233 ms
64 bytes from 192.168.1.1: icmp_seq=19 ttl=64 time=1.642 ms
64 bytes from 192.168.1.1: icmp_seq=20 ttl=64 time=1.593 ms
64 bytes from 192.168.1.1: icmp_seq=21 ttl=64 time=4.049 ms
64 bytes from 192.168.1.1: icmp_seq=22 ttl=64 time=4.223 ms
64 bytes from 192.168.1.1: icmp_seq=23 ttl=64 time=4.136 ms
64 bytes from 192.168.1.1: icmp_seq=24 ttl=64 time=1.277 ms
64 bytes from 192.168.1.1: icmp_seq=25 ttl=64 time=3.088 ms
64 bytes from 192.168.1.1: icmp_seq=26 ttl=64 time=4.268 ms
64 bytes from 192.168.1.1: icmp_seq=27 ttl=64 time=13.463 ms
64 bytes from 192.168.1.1: icmp_seq=28 ttl=64 time=4.167 ms
64 bytes from 192.168.1.1: icmp_seq=29 ttl=64 time=3.606 ms
64 bytes from 192.168.1.1: icmp_seq=30 ttl=64 time=2.931 ms
64 bytes from 192.168.1.1: icmp_seq=31 ttl=64 time=4.184 ms
64 bytes from 192.168.1.1: icmp_seq=32 ttl=64 time=4.071 ms
64 bytes from 192.168.1.1: icmp_seq=33 ttl=64 time=201.332 ms
64 bytes from 192.168.1.1: icmp_seq=34 ttl=64 time=218.367 ms
64 bytes from 192.168.1.1: icmp_seq=35 ttl=64 time=247.544 ms
64 bytes from 192.168.1.1: icmp_seq=36 ttl=64 time=57.321 ms
64 bytes from 192.168.1.1: icmp_seq=37 ttl=64 time=13.694 ms
64 bytes from 192.168.1.1: icmp_seq=38 ttl=64 time=3.918 ms
64 bytes from 192.168.1.1: icmp_seq=39 ttl=64 time=2.748 ms
64 bytes from 192.168.1.1: icmp_seq=40 ttl=64 time=1.839 ms
64 bytes from 192.168.1.1: icmp_seq=41 ttl=64 time=4.141 ms
64 bytes from 192.168.1.1: icmp_seq=42 ttl=64 time=3.919 ms
64 bytes from 192.168.1.1: icmp_seq=43 ttl=64 time=4.114 ms
64 bytes from 192.168.1.1: icmp_seq=44 ttl=64 time=1.316 ms
64 bytes from 192.168.1.1: icmp_seq=45 ttl=64 time=2.634 ms
64 bytes from 192.168.1.1: icmp_seq=46 ttl=64 time=10.943 ms
64 bytes from 192.168.1.1: icmp_seq=47 ttl=64 time=144.553 ms
64 bytes from 192.168.1.1: icmp_seq=48 ttl=64 time=158.767 ms
64 bytes from 192.168.1.1: icmp_seq=49 ttl=64 time=865.861 ms
64 bytes from 192.168.1.1: icmp_seq=50 ttl=64 time=1.009 ms
64 bytes from 192.168.1.1: icmp_seq=51 ttl=64 time=1.281 ms
64 bytes from 192.168.1.1: icmp_seq=52 ttl=64 time=1.199 ms
64 bytes from 192.168.1.1: icmp_seq=53 ttl=64 time=4.212 ms
64 bytes from 192.168.1.1: icmp_seq=54 ttl=64 time=1.714 ms
64 bytes from 192.168.1.1: icmp_seq=55 ttl=64 time=4.053 ms
64 bytes from 192.168.1.1: icmp_seq=56 ttl=64 time=21.046 ms
64 bytes from 192.168.1.1: icmp_seq=57 ttl=64 time=13.619 ms
64 bytes from 192.168.1.1: icmp_seq=58 ttl=64 time=14.630 ms
64 bytes from 192.168.1.1: icmp_seq=59 ttl=64 time=3.883 ms
64 bytes from 192.168.1.1: icmp_seq=60 ttl=64 time=4.119 ms
64 bytes from 192.168.1.1: icmp_seq=61 ttl=64 time=1.196 ms
64 bytes from 192.168.1.1: icmp_seq=62 ttl=64 time=4.048 ms
64 bytes from 192.168.1.1: icmp_seq=63 ttl=64 time=1.028 ms
64 bytes from 192.168.1.1: icmp_seq=64 ttl=64 time=1.116 ms
64 bytes from 192.168.1.1: icmp_seq=65 ttl=64 time=4.039 ms
64 bytes from 192.168.1.1: icmp_seq=66 ttl=64 time=16.272 ms
64 bytes from 192.168.1.1: icmp_seq=67 ttl=64 time=9.359 ms
64 bytes from 192.168.1.1: icmp_seq=68 ttl=64 time=29.070 ms
64 bytes from 192.168.1.1: icmp_seq=69 ttl=64 time=1.125 ms
64 bytes from 192.168.1.1: icmp_seq=70 ttl=64 time=3.871 ms
64 bytes from 192.168.1.1: icmp_seq=71 ttl=64 time=110.853 ms
64 bytes from 192.168.1.1: icmp_seq=72 ttl=64 time=131.584 ms
64 bytes from 192.168.1.1: icmp_seq=73 ttl=64 time=154.010 ms
64 bytes from 192.168.1.1: icmp_seq=74 ttl=64 time=1.178 ms
64 bytes from 192.168.1.1: icmp_seq=75 ttl=64 time=4.243 ms
64 bytes from 192.168.1.1: icmp_seq=76 ttl=64 time=9.988 ms
64 bytes from 192.168.1.1: icmp_seq=77 ttl=64 time=5.705 ms
64 bytes from 192.168.1.1: icmp_seq=78 ttl=64 time=19.701 ms
64 bytes from 192.168.1.1: icmp_seq=79 ttl=64 time=18.000 ms
64 bytes from 192.168.1.1: icmp_seq=80 ttl=64 time=3.954 ms
64 bytes from 192.168.1.1: icmp_seq=81 ttl=64 time=4.209 ms
64 bytes from 192.168.1.1: icmp_seq=82 ttl=64 time=1.173 ms
64 bytes from 192.168.1.1: icmp_seq=83 ttl=64 time=4.098 ms
64 bytes from 192.168.1.1: icmp_seq=84 ttl=64 time=3.956 ms
64 bytes from 192.168.1.1: icmp_seq=85 ttl=64 time=4.100 ms
64 bytes from 192.168.1.1: icmp_seq=86 ttl=64 time=16.471 ms
64 bytes from 192.168.1.1: icmp_seq=87 ttl=64 time=1.033 ms
64 bytes from 192.168.1.1: icmp_seq=88 ttl=64 time=4.681 ms
64 bytes from 192.168.1.1: icmp_seq=89 ttl=64 time=3.924 ms
64 bytes from 192.168.1.1: icmp_seq=90 ttl=64 time=4.040 ms
64 bytes from 192.168.1.1: icmp_seq=91 ttl=64 time=1.603 ms
64 bytes from 192.168.1.1: icmp_seq=92 ttl=64 time=1.626 ms
64 bytes from 192.168.1.1: icmp_seq=93 ttl=64 time=4.064 ms
64 bytes from 192.168.1.1: icmp_seq=94 ttl=64 time=3.708 ms
64 bytes from 192.168.1.1: icmp_seq=95 ttl=64 time=46.434 ms
Request timeout for icmp_seq 96
64 bytes from 192.168.1.1: icmp_seq=96 ttl=64 time=1104.146 ms
64 bytes from 192.168.1.1: icmp_seq=97 ttl=64 time=794.081 ms
64 bytes from 192.168.1.1: icmp_seq=98 ttl=64 time=1.135 ms
64 bytes from 192.168.1.1: icmp_seq=99 ttl=64 time=3.810 ms
64 bytes from 192.168.1.1: icmp_seq=100 ttl=64 time=3.683 ms
64 bytes from 192.168.1.1: icmp_seq=101 ttl=64 time=4.350 ms
64 bytes from 192.168.1.1: icmp_seq=102 ttl=64 time=4.148 ms
64 bytes from 192.168.1.1: icmp_seq=103 ttl=64 time=3.907 ms
64 bytes from 192.168.1.1: icmp_seq=104 ttl=64 time=3.768 ms
64 bytes from 192.168.1.1: icmp_seq=105 ttl=64 time=1.644 ms
64 bytes from 192.168.1.1: icmp_seq=106 ttl=64 time=7.536 ms
64 bytes from 192.168.1.1: icmp_seq=107 ttl=64 time=7.881 ms
64 bytes from 192.168.1.1: icmp_seq=108 ttl=64 time=3.987 ms
64 bytes from 192.168.1.1: icmp_seq=109 ttl=64 time=1.364 ms
64 bytes from 192.168.1.1: icmp_seq=110 ttl=64 time=1.251 ms
64 bytes from 192.168.1.1: icmp_seq=111 ttl=64 time=1.632 ms
64 bytes from 192.168.1.1: icmp_seq=112 ttl=64 time=4.191 ms
64 bytes from 192.168.1.1: icmp_seq=113 ttl=64 time=4.285 ms
64 bytes from 192.168.1.1: icmp_seq=114 ttl=64 time=3.966 ms
64 bytes from 192.168.1.1: icmp_seq=115 ttl=64 time=1.419 ms
64 bytes from 192.168.1.1: icmp_seq=116 ttl=64 time=108.544 ms
64 bytes from 192.168.1.1: icmp_seq=117 ttl=64 time=52.418 ms
64 bytes from 192.168.1.1: icmp_seq=118 ttl=64 time=3.854 ms
64 bytes from 192.168.1.1: icmp_seq=119 ttl=64 time=486.287 ms
--- 192.168.1.1 ping statistics ---
120 packets transmitted, 120 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 1.009/52.774/1104.146/159.580 ms
每隔 10-20 秒左右，連線就會嚴重下降。 ping 時間可能超過 1000 毫秒（並且經常出現封包遺失），頻寬從超過 70 MB/s 變為數百 KB/s，有時甚至為 0（使用 TCP 和 UDP 使用 iperf3 進行測試） 。
我嘗試了一切。我嘗試將 5GHz 接入點設定為僅 802.11ac，將 2.4GHz 接入點設定為僅 802.11n。我嘗試了兩個接入點的每個通道和通道寬度。我嘗試禁用身份驗證。我嘗試安裝最新的韌體，並嘗試安裝DD-WRT。沒有什麼差別。
我突然想到，這可能是外界的干擾。我嘗試將 MacBook 連接到啟用無線熱點的手機。連線定期降級，就像連接到路由器時一樣。我還嘗試連接到鄰居的無線網路（2.4GHz）（當然要經過他們的許可），同樣的情況也發生在那裡。
我還使用我兄弟的 Windows PC 確認了這一切，所以這不是我的 MacBook 的錯。為了更好地衡量，我還嘗試關閉公寓中的所有設備，包括我自己的路由器、電視、無線耳機和所有電腦。我還拔掉了微波爐和電視的插頭。這沒有什麼區別。
有人知道會發生什麼事嗎？哪個設備連接到哪個其他設備似乎並不重要，相同的無線連接降級總是會發生。什麼樣的家用設備可能會導致這種情況？我可以做什麼來找出答案？