Unable to configure Raspberry pi 3 B+ as a 5Ghz AP using 802.11ac in India

Question

I have been trying to configure my Raspberry pi 3 B+ as a 5Ghz access point but I'm unable to do so. Here is my hostapd config:

country_code=IN
ieee80211d=1 
ieee80211h=1

interface=wlan0
driver=nl80211

wpa=2
wpa_key_mgmt=WPA-PSK
rsn_pairwise=CCMP
wmm_enabled=1
ht_capab=[HT40][SHORT-GI-20][DSSS_CK-40]
macaddr_acl=0
ignore_broadcast_ssid=0
auth_algs=1


hw_mode=a
ieee80211n=1
require_ht=1
ieee80211ac=1
require_vht=1

vht_oper_chwidth=1
channel=36
vht_oper_centr_freq_seg0_idx=42

I get the following error

Failed to create interface mon.wlan0: -95 (Operation not supported)
wlan0: interface state UNINTIALIZED->COUNTRY_UPDATE
Could not set channel for kernel driver
Interface initialization failed
wlan0: interface state COUNTRY_UPDATE->DISABLED
wlan0: AP-DISABLED
hostapd_free_hapd_data: Interface wlan0 wasn't started
nl80211: deinit ifname=wlan0 disabled_llb_rates=0

I also tried setting channel=0 and channel=acs_survey but I keep getting the same error. How do I resolve this error?
What is the proper hostapd for configuring my raspberry pi 3 B+ as 5Ghz AP? Is it possible to utilize dual-band(2.4Ghz and 5Ghz) of the raspberry pi for an AP simultaneously?

If so, please post the hostapd for that too. Thanks in advance.

Answer 1

Try starting with channel=48 and without using acs_survey. Once you get something working you can experiment from there.

Answer 2

Use "pi-ap"- it will automate configuration of a Pi as Access Point with 802.11ac support:

https://raspberrypi.stackexchange.com/a/104175/97613

It's been up on Github for about 5 months and folks seem to rate it-