The HQ-100A was introduced in 1961 as an update to the HQ-100. The variable BFO and the 24 hour clock option was the main change. However, it wasn't much advertised in QST, probably because there were other models that appealed more to hams. For example, ads for the HQ-170 and the HQ-180 were very common. Even the HQ-110 appeared more. There was a brief QST review of the new receiver in the December 1961 issue. A dedicated full page add eventually appeared in 1962. It probably was more common on shortwave magazines.