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Collins Radio

Collins Radio was responsible for some of the most advanced radio technology available between the 1940s and the 1970s. In the 1930s the company, headed by Art Collins[?], produced transmitters only, and targetted the AM broadcast market among other things. After the war, the company got seriously into receivers, and was to design some of the best receivers available in the next few decades. Their products were now targetted to the military, amateur radio, and commercial sectors.

Around 1947, the company introduced their first amateur receiver, the 75A-1. This set achieved excellent stability for the time due to high build quality and the use of a permeability tuned oscillator[?] (PTO) in its second conversion stage. It was one of the few double conversion superheterodynes on the market and covered only the amateur bands. It was quite expensive, as almost all Collins receivers have been.

With the experience gained in the design of the 75A-1, Collins released the 51J-1 receiver, a general coverage HF set (covering .5 to 30 MHz). It performed well and would be produced, in somewhat updated versions (51J-2, 51J-3, 51J-4) for about a decade. It found much use in military and commercial settings but was much too expensive for most enthusiasts. In the military it was known as R-388 and was much used in multiple receiver diversity RTTY installations.

The 75A-2 was an evolutionary improvement over the 75A-1, andIn 1 the 75A-3 was the next step, while introducing an improtant new feature: the Collins mechanical filter. This device allowed the receiver to achieve excellent selectivity to complement its excellent stability. The 75A-4 (1954) improved upon its predecessors in many ways, offering state-of-the-art selectivity, sensitivity and stability along with intereference fighting tools, and was one of the first receivers expressedly designed for single sideband reception. Its performance is very well regarded even today.

Around 1950, Collins began designing the R-390 (.5 - 30 MHz) for the US military. This was intended to be a receiver of the highest performance available, with the ruggedness and serviceability required for military duty. It featured direct mechanical digital frequency readout. The set is a marvel of electrical and mechanical design and can still outperform all but the best modern receivers. It is broken into several modules for easy field repair. Sets of the original 1951 contract cost the government over $2000 each. Around 16,000 were produced. The R-389, a longwave version, was designed concurrently but under 1000 were made.

About 3 years later, Collins delivered the R-390A to the military. While nominally a cost reduced R-390 (savings of about $250 each), its design compromises were minimal and it added mechanical filters for improved selectivity. Mechanics were redesigned to be simpler. About 54,000 were produced and the set was a military workhorse until the 1970s. Like the R-390, it can outperform many modern radios.

In the amateur market, Collins replaced the 75A series with the much smaller 75S series. These featured mechanical filters, very accurate frequency readout, and excellent stability. At the request of the US government, Collins designed the 51S-1 general coverage set, which was essentially (in intended use) a physically smaller replacement for the 51J series for the armed forces. It was not intended as a replacement for the higher performance R-390A; the sets were used simultaneously. It was also successful in the commercial market, and was fairly expensive.

Collins produced a few high performance solid state receivers in the 1970s, such as the 651S-1. These are desireable today and feature the good performance expected of their brand. Collins was acquired in the 1970s by Rockwell and continues to design communications equipment today under the name Rockwell Collins. They are highly concentrated in the defense market and no longer market receivers to the public. The Collins mechanical filter is still in production and does, however, find consumer and commercial use.



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