A Wireless Local Area Network device, comprising: multiple transmission/reception chains, including one or more first transmission/reception chains and one or more second transmission/reception chains, wherein the one or more first transmission/reception chains are tuned to a first channel, and the one or more second transmission/reception chains are selectively tuned to the first channel or to a second channel, different from the first channel; and control circuitry, configured to receive, via at least one of the transmission/reception chains, a frame preamble signal comprising a first part and a second part, which are both transmitted over either the first channel alone or over both the first channel and the second channel, wherein the first part is decodable from the first channel alone; characterized in that the first part of the frame preamble signal includes a field having two bits indicative of a bandwidth mode used, wherein the field is encoded using an Error Correction Code; and in that the control circuitry is further configured to: decode a portion of the first part, said portion containing the two bits before receiving the entire first part and without decoding the Error Correction Code over the entire field; make a decision, based on the decoded two bits that were decoded before receiving the entire first part and without decoding the Error Correction Code over the entire field, whether the second part is transmitted over the first channel alone or over both the first channel and the second channel; and tune the one or more second transmission/reception chains to the first channel or to the second channel, based on the decision. multiple transmission/reception chains, including one or more first transmission/reception chains and one or more second transmission/reception chains, wherein the one or more first transmission/reception chains are tuned to a first channel, and the one or more second transmission/reception chains are selectively tuned to the first channel or to a second channel, different from the first channel; and control circuitry, configured to receive, via at least one of the transmission/reception chains, a frame preamble signal comprising a first part and a second part, which are both transmitted over either the first channel alone or over both the first channel and the second channel, wherein the first part is decodable from the first channel alone; characterized in that the first part of the frame preamble signal includes a field having two bits indicative of a bandwidth mode used, wherein the field is encoded using an Error Correction Code; and in that the control circuitry is further configured to: decode a portion of the first part, said portion containing the two bits before receiving the entire first part and without decoding the Error Correction Code over the entire field; make a decision, based on the decoded two bits that were decoded before receiving the entire first part and without decoding the Error Correction Code over the entire field, whether the second part is transmitted over the first channel alone or over both the first channel and the second channel; and tune the one or more second transmission/reception chains to the first channel or to the second channel, based on the decision. decode a portion of the first part, said portion containing the two bits before receiving the entire first part and without decoding the Error Correction Code over the entire field; make a decision, based on the decoded two bits that were decoded before receiving the entire first part and without decoding the Error Correction Code over the entire field, whether the second part is transmitted over the first channel alone or over both the first channel and the second channel; and tune the one or more second transmission/reception chains to the first channel or to the second channel, based on the decision.