Dating vintage radios Camcamchat net
The RHQ was also identified as the AGU receiver in some uses.Also, National produced a long wave receiver built along the same lines as these early airways receivers, the RIO.
Or, if the ham couldn't wait, he could opt for the Hammarlund Comet Pro, the only other commercially-built shortwave superhet available at the time.
The RIO didn't use plug-in coils but had two switched tuning ranges that covered frequencies below 500kc.
I have owned the RHM receiver shown above since 1990.
By the early thirties, National had grown from a company that produced radio parts and regenerative TRF receivers into one of the top shortwave receiver producers in the country.
National's chief engineer and general manager, James Millen, had guided the company from its early radio designs (that usually had National as a parts supplier) into the new shortwave receiver market that was becoming popular by 1930.