Macから周囲のWi-Fi電波状況をカンタンに確認する方法:Mac Tips
https://japanese.engadget.com/2015/10/28/mac-wi-fi-mac-tips/

結果

左２つは、WiFiルータ。その右はMacintosh miniのインタネット共有, 一番右はWimax。
測定場所は異なる。

	11a	11g	mac	wimax
RSSI	-57 dBm	-54 dBm	-41 dBm	-25dBm
Noise	-92dBm	-90 dBm	-88 dBm	-98dBm
Tx Rate	527.0 Mbps	145.0 Mbps	217.0 Mbps	145.0 Mbps
PHY Mode	11ac	11n	11n	11n
MCS Index	6	15	23	15
Channel	36(80 MHz, Active)	3(20 MHz, Active)	11 (20 MHz, Active)	7 (20 MHz, Active)
BTC Mode	Unavailable	Hybrid	Hybrid	Hybrid

用語(term)

RSSI: Receive signal strength indicator
値がマイナスの場合は、ゼロに近い方がよい。ただし、干渉などがないかの測定も必要。
RSSIについて　IBS Japan
http://www.ibsjapan.co.jp/tech/details/metageek-solution/understanding-rssi.html

Noise（雑音）

Tx: Transmit
Rx: Receive

#起動(start up)
Finderの「移動」メニューで「コンピュータ」
「MacintoshHD」「システム」「ライブラリ」「CoreServices」「Applications」「ワイヤレス診断」を選ぶ。

「続ける」「続ける」「続ける」を押す。

「完了までに数分かかる場合があります」と表示される。

数分って何分じゃ。

もう一度やり直し。

今度は、全画面を保存。

「続ける」を押す。

「続ける」を押す。今度は、何分かかるか計ってみた。

７分かかった。一番上の画面と同じ画面が出た。

もう一回計った。

$ cd /var/tmp
$ ls -al
-rw-r--r--   1 ogawakiyoshi   wheel  378657993  3 13 21:02 ワイヤレス診断_C02P400HG3QR_2019-03-13_21.02.41.tar.gz
-rw-r--r--   1 ogawakiyoshi   wheel  399167978  3 13 21:13 ワイヤレス診断_C02P400HG3QR_2019-03-13_21.13.41.tar.gz
-rw-r--r--   1 ogawakiyoshi   wheel  406643413  3 13 21:22 ワイヤレス診断_C02P400HG3QR_2019-03-13_21.22.18.tar.gz

$ tar -xzvf ワイヤレス診断_C02P400HG3QR_2019-03-13_21.22.18.tar.gz 
x ./: Can't update time for .
x ./en0_tcpdump.pcap
x ./ctc-g-714400-diagnostics.txt
x ./sw_vers.txt
x ./wifi-03-13-2019__21:15:37.729.log.tgz
x ./wifi_status.txt
x ./wifi-03-13-2019__21:15:51.020.log.tgz
x ./awdl-03-13-2019__21:01:22.728.pcap.tgz
x ./pmset_everything.txt
x ./com.apple.Bluetooth.plist
x ./network_status.txt
x ./darwinup_list.txt
x ./awdl-03-13-2019__21:01:26.868.pcap.tgz
x ./netstat-POST.txt
x ./ipconfig.txt
x ./awdl-03-13-2019__21:06:50.976.pcap.tgz
x ./BluetoothPacketLog.pklg
x ./wifi-03-13-2019__21:12:42.855.log.tgz
x ./leaky_ap_stats.txt
x ./corecaptured.log.tgz
x ./netstat-PRE.txt
x ./traceroute.txt
x ./debug-log.txt
x ./ctc-a-714400-diagnostics.txt
x ./wifi_scan.txt
x ./wifi.log.tgz
x ./event_history.txt
x ./ioreg.txt
x ./com.apple.airport.preferences.plist
x ./arp.txt
x ./configd-store.plist: Can't unlink already-existing object
x ./wifi-03-13-2019__21:15:48.315.log.tgz
x ./bluetooth_status.txt
x ./awdl-03-13-2019__21:07:21.882.pcap.tgz
x ./wifi.log.0.bz2
x ./CoreCapture/
x ./sysdiagnose_2019.03.13_21-16-28+0900_Mac_OS_X_MacBookPro11-1_17G4015.tar.gz
x ./ICLOUD_com.apple.wifi.WiFiAgent.plist
x ./system_profiler.spx
x ./diagnostics-env.txt
x ./kextstat.txt
x ./wifi-03-13-2019__21:12:42.252.log.tgz
x ./preferences.plist
x ./wifi-03-13-2019__21:12:46.296.log.tgz
x ./ifconfig.txt
x ./ndp.txt
x ./ping.txt
x ./awdl-03-13-2019__20:55:06.928.pcap.tgz
x ./awdl_status.txt
x ./bonjour_records.txt
x ./diagnostics.txt
x ./crashes_and_spins/
x ./crashes_and_spins/._fud_2019-03-13-070504_OgawaKiyoshi-no-MacBook-Pro.crash
x ./crashes_and_spins/fud_2019-03-13-070504_OgawaKiyoshi-no-MacBook-Pro.crash
x ./CoreCapture/[2019-03-13_15,25,35.646890]=AuthFail{sts:5,rsn:0}.tgz
x ./CoreCapture/[2019-03-13_21,01,22.307029]=WiFiDebug~PRE[8E742].tgz
x ./CoreCapture/[2019-03-13_16,02,39.012122]=RoamFail{sts:1,rsn:3}.tgz
x ./CoreCapture/[2019-03-13_21,15,37.324975]=WiFiDebug~PRE[1F3CE].tgz
x ./CoreCapture/[2019-03-13_21,06,50.573801]=WiFiDebug~PRE[AC409].tgz
x ./CoreCapture/[2019-03-13_15,25,20.630626]=AssocFail{sts:5,rsn:0}.tgz
x ./CoreCapture/[2019-03-13_21,12,41.850050]=WiFiDebug~PRE[3AACF].tgz
x ./CoreCapture/[2019-03-13_21,15,47.905769]=WiFiDebug~POST[1F3CE].tgz
x ./CoreCapture/[2019-03-13_16,02,38.626633]=AuthFail{sts:5,rsn:0}.tgz
x ./CoreCapture/[2019-03-13_20,54,57.061458]=WiFiDebug~PRE[D2DF6].tgz
x ./CoreCapture/[2019-03-13_18,38,16.777973]=RoamFail{sts:1,rsn:3}.tgz
x ./CoreCapture/[2019-03-13_15,25,23.935804]=AuthFail{sts:5,rsn:0}.tgz
x ./CoreCapture/[2019-03-13_14,38,05.199230]=RoamFail{sts:1,rsn:4}.tgz
x ./CoreCapture/[2019-03-13_21,12,45.876790]=WiFiDebug~POST[3AACF].tgz
x ./CoreCapture/[2019-03-13_14,38,04.803831]=AuthFail{sts:5,rsn:0}.tgz
x ./CoreCapture/[2019-03-13_20,55,06.519543]=WiFiDebug~POST[D2DF6].tgz
x ./CoreCapture/[2019-03-13_21,07,21.357726]=WiFiDebug~POST[AC409].tgz
x ./CoreCapture/[2019-03-13_21,01,26.468066]=WiFiDebug~POST[8E742].tgz
x ./CoreCapture/[2019-03-13_18,38,16.389917]=AuthFail{sts:5,rsn:0}.tgz
tar: Error exit delayed from previous errors.

１台のルータで 11a, 11gの２つの経路がある。両方のファイルを比較。
固有の情報は削除。

$ cat ctc-a-714400-diagnostics.txt 
# --- Diagnostics (ctc-a-714400)

————————————————————————————————————————————————————————————————————————————————————————————————————————
Timestamp    Name                          Duration    Result    Description                            
————————————————————————————————————————————————————————————————————————————————————————————————————————
21:15:47.566 Hidden Wi-Fi Scan Results     0.001       Yes       Found 2 hidden network(s)
21:15:47.509 AirPort Base Station          0.001       No        Current network is not an AirPort Base Station
21:15:47.444 PNL Contains Hidden           0.030       Yes       PNL contains hidden networks
                                                                 
21:15:47.411 Large PNL                     0.031       Yes       Wi-Fi PNL count (216)
21:15:46.972 Custom Web Proxy              0.000       Yes       Detected custom web proxy settings
21:14:43.085 Ping WAN (CFNetwork)          0.001       No        Could not ping DNS server(s) (2)
                                                                 192.168.0.1 / 0.00ms / BE / 64 bytes
                                                                 2402:6b00:3e94:e600:1266:82ff:fe0d:42d4 / 0.00ms / BE / 64 bytes
21:14:43.051 Ping LAN (CFNetwork)          0.034       No        Could not ping router
21:07:21.016 No Scan Results               0.000       Yes       No Wi-Fi networks are visible


$ cat ctc-g-714400-diagnostics.txt 
# --- Diagnostics (ctc-g-714400)

————————————————————————————————————————————————————————————————————————————————————————————————————————
Timestamp    Name                          Duration    Result    Description                            
————————————————————————————————————————————————————————————————————————————————————————————————————————
20:55:06.165 Hidden Wi-Fi Scan Results     0.000       Yes       Found 1 hidden network(s)
20:55:06.108 AirPort Base Station          0.001       No        Current network is not an AirPort Base Station
20:55:06.040 PNL Contains Hidden           0.032       Yes       PNL contains hidden networks
                                                                 20:55:06.003 Large PNL                     0.034       Yes       Wi-Fi PNL count (215)
20:55:05.732 BT Coex Active                0.079       Yes       Bluetooth coexistence is active
20:55:05.590 Custom Web Proxy              0.000       Yes       Detected custom web proxy settings
20:54:06.020 Retrieve Apple Over WiFi      1.641       No        Could not retrieve 'https://captive.apple.com' over Wi-Fi
20:54:05.933 Ping WAN (CFNetwork)          0.001       No        Could not ping DNS server(s) (2)
                                                                 192.168.0.1 / 0.00ms / BE / 64 bytes
                                                                 2402:6b00:3e94:e600:1266:82ff:fe0d:42d4 / 0.00ms / BE / 64 bytes
20:54:05.899 Ping LAN (CFNetwork)          0.034       No        Could not ping router

測定中に接続していたのは、aの方。
gの方に変えて再測定。

$ diff wifi_status.txt  ../wifi_status.txt 
7,11c7,11
<     SSID                 : ctc-g-714400
<     BSSID                : 10:66:82:0d:42:d6
<     RSSI                 : -54 dBm
<     Noise                : -90 dBm
<     Tx Rate              : 145.0 Mbps
---
>     SSID                 : ctc-a-714400
>     BSSID                : 10:66:82:0d:42:d7
>     RSSI                 : -57 dBm
>     Noise                : -92 dBm
>     Tx Rate              : 527.0 Mbps
13,14c13,14
<     PHY Mode             : 11n
<     MCS Index            : 15
---
>     PHY Mode             : 11ac
>     MCS Index            : 6
17c17
<     Channel              : 3 (20 MHz, Active)
---
>     Channel              : 36 (80 MHz, Active)
28c28
<     BTC Mode             : Hybrid
---
>     BTC Mode             : Unavailable
34,35c34,35
<       Min                : 4
<       Max                : 13
---
>       Min                : 7
>       Max                : 14
39,40c39,40
<       Min                : 4
<       Max                : 13
---
>       Min                : 7
>       Max                : 14
44,45c44,45
<       Min                : 4
<       Max                : 13
---
>       Min                : 7
>       Max                : 14