Ummmm ... I think Art Collins might have beat Heath to that with the KWM-2 and external VFO, sometime around 1959, followed by the S-Line. 73, Fred K6DGW - Northern California Contest Club - CU in the 50th Running of the Cal QSO Party 3-4 Oct 2015 - www.cqp.org On 2/7/2015 11:55 AM, Bob wrote: > 1st split capable RX-TX was Heath SB300-SB400 pair.