An access point (AP) includes at least one processing circuitry configured to support communications with other WDEV(s) and to generate and process signals for such communications. In some examples, the device includes a communication interface and a processing circuitry, among other possible circuitries, components, elements, etc. to support communications with other WDEV(s) and to generate and process signals for such communications. The WDEV transmits a null data packet (NDP) announcement frame that specifies a sub-carrier (SC) or tone grouping factor, a communication channel bandwidth, and other WDEV(s) to respond with beamforming feedback. The WDEV process the NDP announcement frame to determine if it is to respond, and if so, then receives an NDP sounding frame that includes long training fields (LTFs) and pilots at predetermined locations and generates beamforming feedback of communication channel estimates at SCs as determined based on a sub-carrier roster look up table (LUT).