Tube-equipped receivers from Collins
In 1932, radio amateur Arthur A. Collins founded his own company Collins Radio Company in Cedar Rapids, initially manufacturing amateur radio transmitters. In the following years, Collins got an excellent reputation in the commercial and, above all, aeronautical communications sector. Based on the receivers and transmitters manufactured during the Second World War, amateur radio receivers (the 75-A series) were first available from Collins in 1946.
Communications receivers with continuous shortwave coverage not limited to the amateur radio bands were produced after 1949, based on the model 51J-1. The receivers covered the frequency range from 500 kHz to 30.5 MHz in 1 MHz bands, the linear frequency response allowed a dial reading accuracy of 1 KHz that had never been achieved before. The heavy black receivers became famous with the successor model 51J-3 (military version R-388), equipped with coil filters and manufactured from 1952, and with the 51J-4 (military version R-388A), only this receiver, available from 1957, was equipped with the legendary mechanical Collins filters.
Successor in the military sector was in 1951 the R-390 with the mechanical digital frequency display (the frequency was displayed on a kind of odometer, fine divisions up to 200 Hz) and the R-390A, unsurpassed in AM especially in tropical shortwave bands reception, only this model came with the legendary mechanical filters 16 / 8 / 4 / 2 / 1 / 0.1 kHz.
In the civilian sector, a series of sets with smaller dimensions followed, the amateur radio receivers of the 75S series, which only covered the amateur radio bands, and then - again with a continuous frequency coverage - the 51S-1, manufactured from 1959 on, which covered the frequency range from 200 kHz to 30 MHz in 1 MHz sections with a dial reading accuracy of less than 500 Hz, it was still fully equipped with tubes.
In 1974 Collins was taken over by Rockwell Intl. and has since continued to be active in military and aeronautical communications apart from high-end amateur sets manufactured in small numbers.
Collins Radio Co. receivers
|(51J) / TCS||1943||Single Conversion||1.5 - 12 MHz||AM, CW, SSB|
|51J-3||1952||Triple Conversion||540 kHz - 30.5 MHz||AM, CW, SSB|
|51J-4 / R-388A||1957||Triple Conversion||540 kHz - 30.5 MHz||AM, CW, SSB; mechanical filters 1.5 / 3 / 6 MHz|
|R-390||1951||Triple Conversion||500 kHz - 32 MHz||AM, CW, SSB|
|R-390A||1954||Triple Conversion||500 kHz - 32 MHz||AM, CW, SSB; mechanical filters 100 Hz / 1 / 2 / 4 / 8 / 16 kHz|
|R-392||1954||Triple Conversion||500 kHz - 32 MHz||AM, CW, SSB, Coils - Filter 2 / 4 / 8 kHz|
|51S-1||1959||Double/triple Conversion||200 kHz - 30 MHz||AM, LSB, USB, CW; older sets with winged logo, newer with round logo|
|651S-1||1971/3||Triple Conversion||400 kHz (opt. 12 kHz) - 30 MHz||AM, LSB, USB, CW, NBFM (opt); older units with combined mode / bandwidth switch; newer ones with separate mode & bandwidth switches|
|851S-1||1982||Triple Conversion||250 kHz (optionally 12 kHz) - 30 MHz||AM, LSB, USB, CW|