Slow TX and absymal RX speeds with mt7610u device

[danielshub]

I have a Panda PAU0a AC600 USB WiFi adapter (mt7610u chipset) installed in a Intel NUC13 i5 that is running Arch Linux. I configured hostapd based on your guide.

 # cat /etc/hostapd/hostapd.conf
ssid=NUC13AP
bridge=home0
interface=wlan0
wpa_passphrase=HelloWorld

country_code=US
hw_mode=a
vht_oper_chwidth=1

channel=36
vht_oper_centr_freq_seg0_idx=42

driver=nl80211

ieee80211d=1
ieee80211h=1
ieee80211ac=1
ieee80211n=1
wmm_enabled=1

auth_algs=1
ignore_broadcast_ssid=0
wpa=2
rsn_pairwise=CCMP
wpa_key_mgmt=WPA-PSK

# Panda Pau0a
ht_capab=[HT40-][HT40+][GF][SHORT-GI-20][SHORT-GI-40][RX-STBC1][DSSS_CCK-40]
vht_capab=[SHORT-GI-80][MAX-A-MPDU-LEN-EXP3][RX-ANTENNA-PATTERN][TX-ANTENNA-PATTERN]

I can start the AP on the NUC 13 without issue

# iw wlan0 info
Interface wlan0
	ifindex 44
	wdev 0x400000001
	addr 9c:ef:d5:f9:40:2e
	ssid NUC13AP
	type AP
	wiphy 4
	channel 36 (5180 MHz), width: 80 MHz, center1: 5210 MHz
	txpower 16.00 dBm
	multicast TXQ:
		qsz-byt	qsz-pkt	flows	drops	marks	overlmt	hashcol	tx-bytes	tx-packets
		0	0	133	0	0	0	0	14984		158

I can also connect from a laptop

$ iw wlp0s20f3 info
Interface wlp0s20f3
	ifindex 2
	wdev 0x1
	addr f0:de:f1:80:47:c0
	ssid NUC13AP
	type managed
	wiphy 0
	channel 36 (5180 MHz), width: 80 MHz, center1: 5210 MHz
	txpower 22.00 dBm
	multicast TXQ:
		qsz-byt	qsz-pkt	flows	drops	marks	overlmt	hashcol	tx-bytes	tx-packets
		0	0	0	0	0	0	0	0		0

The problem is my TX and RX speeds, especially the RX speed, are much slower than I would expect. I measured the speeds by running a iperf3 server on the NUC13 and a iperf3 client on the laptop and placing the laptop and NUC13 about 1 foot apart with no obstructions between them

- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID][Role] Interval           Transfer     Bitrate         Retr
[  5][TX-C]   0.00-10.00  sec  51.6 MBytes  43.3 Mbits/sec    5             sender
[  5][TX-C]   0.00-10.01  sec  50.5 MBytes  42.3 Mbits/sec                  receiver
[  7][RX-C]   0.00-10.00  sec  3.25 MBytes  2.73 Mbits/sec   32             sender
[  7][RX-C]   0.00-10.01  sec  2.38 MBytes  1.99 Mbits/sec                  receiver

If I connect the laptop to the NUC13 via a wired 1000 Mbps connection, I get 900+ Mbps transfer rates. If I connect the laptop to a Unifi 802.11ac AP (channel 40, 80 MHz bandwidth) I can get 200+ Mbps.

Any ideas about what I may have screwed up?