Earl Diamond and RCA Radio Indianapolis in the 1960s and 1970s

Earl Diamond is an electrical engineer who worked for RCA's radio division in Indianapolis, Indiana from 1962 until RCA ceased its radio manufacture in 1974 and closed the division.  During his tenure at RCA, Mr. Diamond designed several well-known RCA portable transistor radios and was kind enough to grant me an interview.
Sarah (S): Describe briefly how you came to be involved in radio engineering.  Was radio work your first choice, or did you end up there?

Mr. Diamond (D): When I was in high school I was interested in electronics, and I decided that I wanted a career in electronic design. My first choice was audio design, however, when I interviewed with RCA, the only opening they had was in AM radio design. I took that position with the idea that I would transfer to audio circuit design when an opening occurred. After a year or two I decided that I wanted to stay in radio design.

S: What roles did you fill at RCA?

D: I started off as the electronic design and project engineer on a small AM portable radio (Model RFG20). The next two years or so I designed two other portable radios (AM Model RGG29 and AM/FM Model RHM39.) Actually there were several versions of each of these radios with slightly different model numbers, but the electronic circuitry was basically the same. 

Starting in 1967 or 1968 RCA engineers started designing a series of console radios using state of the art production processes and components. RCA used the acronym "C/COS" (Computer-Controlled Operating System) to describe it. On these designs, each of the functional building blocks of the radio were put on a separate thick film hybrid microcircuit module which was soldered into the "motherboard." Each of the functional blocks were pre-tested in a test fixture by a computer for key electrical specifications before being wave soldered into the mother board. The motherboard was then completely aligned and tested by human operators controlling computer-operated fixtures on a continuous assembly line. The system in theory, and usually in practice, produced a fully functional radio right off the assembly line. My job during this period was to take the radio design engineer's circuit and divide it into the aforementioned functional blocks. Then, working with the design engineers and the outside manufacturer of the modules, I modified and optimized the circuits for production. Also I designed the tests and wrote the computer test programs that were used to give a "pass/fail" verdict on each module. When a module failed, I was involved in confirming, analyzing, and correcting the problem.

In addition to designing the radios I, as the design engineer was involved in helping resolve any manufacturing problems that arose related to my products during their entire production run.

S: How would you describe the radio development team at RCA?  What was the focus of the radio division when you were there?  Did the radio division eventually cease operations or get transferred overseas?

D: As I look back at the design team at RCA, I am impressed by the talent and professionalism of the engineers that were on the team.  All of the engineers were capable of, and dedicated to, producing a good product. The development team was primarily made up of electronic and mechanical engineers along with electronic technicians and draftsmen, and included engineers from China, Vietnam, India, and Ecuador, as well as the US.  Most of the managers were engineers who had come up through the ranks.

The main focus of the company was to produce high quality products that were better, or at least as good, as similarly priced products made by its competitors.

In mid-1974, a corporate decision was made to design and manufacture all RCA radio products in Japan, and the members of the design team either accepted other positions within RCA, or went to other companies. 

S: Please describe some of the radio models you were involved with. 

D: The basic portable radios I designed were models RFG20, RGG29, and RHM39. Usually there was an additional letter added at the end of the model number to indicate the style and/or color of the case. All of these models were in the product line for 2 or more years. Generally there were minor changes in the case, color, and/or circuitry from one year to the next. Also there were slight changes in the model numbers. For example, the RFG25A was the same basic radio as the RFG20A, except it had a simulated leather case surrounding the plastic front. Similarly, the RHG21N was the same basic radio as the RFG20A, except it was a different color, as indicated by the final letter (N) in the model number, and it was in the third year of manufacture, as indicated by the second letter (H).

Each year the second letter of the model number was increased one step in the alphabet, although I think the letters "O" and "I" were skipped due to their resemblance to the numbers "0" and "1" respectively. The only other feature added to the RFG20A to produce the RHG21N was a larger tuning knob and a better tuning capacitor that allowed more precise tuning.

I don't remember all of model numbers of the console radio models I helped design, but they were all advertised as being designed and manufactured using "CCOS" technology. Some of the circuitry was even used in RCA TV sets.

S: What would be your favorite RCA radio you had a hand in designing? 

D: Of the portable radios I designed, I would have to say the RHM39 series was my favorite. The first two radios I designed were AM-only models. The RHM39 was AM and FM. This was more of a challenge, as it included two separate types of radios in a single package that was about the same size as the AM only radios.

S: What kind of challenges did the design team face in meeting Japanese competition, and staying on top technically and performance-wise?

D: The biggest challenge in competing with the Japanese was cost related. From a technical standpoint I feel the stateside design team was competitive with the Japanese. From a cost standpoint this was not the case. When I first started working for RCA in 1962, practically all of the internal parts of their radios were manufactured in the US. The parts manufactured in Japan soon became less expensive than similar parts in the US. Also the Japanese government, in an effort to eliminate the "low quality" reputation that Japanese products had up to that time, started requiring their products to meet higher quality standards. In order to keep product cost down and compete with other radio manufacturers, as time went by RCA had to start using more and more Japanese parts.

Unfortunately the parts, design, and labor costs in Japan were considerably lower than in the US, so even with tariffs on the finished radios they exported, they could produce equivalent radios less expensively than we could in the US. Eventually competitive pressures forced RCA, and most of the other stateside manufacturers to design and/or manufacture most or all of their product line overseas. 

S: Were all RCA radios designed in Indianapolis?  When did this cease, if it ever did?

D: Up until 1961 RCA transistor portable radios were designed in Cherry Hill, New Jersey. In 1961 the design team moved to Indianapolis, and most of the radios were designed there until mid-1974, after which the design of RCA radio products was done in Japan. Actually during the mid-1960s and early 1970s, RCA imported a few of their radio designs from Japan, but the vast majority were designed here in the US. In 1986 RCA was purchased by GE. Then in 1988 GE sold its consumer electronics business (which included radio) to Thomson Multimedia, a company owned by the French government. To the best of my knowledge, all RCA radio products are still designed in Japan.

S: Out of all the RCA transistor radios you are familiar with, which do you feel offered the best performance, and why?

D: After all these years, I have forgotten the model numbers of most of the radios that were produced while I was at RCA, but of the portables that I designed, the RHG30 (a revised RGG29) had the best overall AM performance.

There were a number of reasons for this. This unit cost more than the other AM only models, allowing the use of more parts and higher performance parts. This unit was also larger than the other portables, allowing for a larger ferrite antenna, and a larger acoustic enclosure and speaker, as well as an audio feedback circuit that reduced distortion. There were several different model numbers associated with this series over the years, but the ones with a plastic-only case had slightly better performance than the models with a combination plastic and simulated leather case. The proximity of the simulated leather case to the ferrite antenna degraded the sensitivity and other characteristics slightly. I was never happy with the styling of this radio series, but I think the performance was better than average. There was also another AM portable designed by one of my coworkers that had excellent performance, but I don't recall the model number.

In general, all of the "console" models had better performance than the portables, due to the fact that the designer could spend more on parts, and was not constrained as much on size and low battery voltage. Most of the console models in a given model year had the same basic chassis, although some had a few extra "bells and whistles." One of the best chassis I recall was the RC1229. Also there was a series of consoles that used "CCOS" technology that had good performance, however there was a brief period of time when one of our purchased component vendors had a static noise problem on a small percentage of one of the electronic hybrid microcircuits. The problem was not caught by quality control because of the nature of the defect. The problem only occurred under several severe simultaneous operating conditions after weeks of use in a high humidity environment. There is always a risk of latent defects of this nature on early products that use new "cutting edge" technology for the first time. The problem was corrected quickly once it was identified. 

S: Which RCA radio to you offered the best combination of performance and value (bang for the buck)? 

D: This is a hard question to answer for a number of reasons. Each radio in the product line is designed to fit a specific niche in the market. For example, some people want a radio that will not only pick up AM and FM, but will also pick up shortwave or other bands. Others want AM and FM only, or even just AM only. Similarly, some people are interested in excellent performance on one band, but are not too concerned about the performance in other bands. 

Another factor to be considered is how and where the radio is to be used. For example, if the radio is going to be primarily used in a metropolitan area, and only local stations are desired, sensitivity is not as important as AGC and overload characteristics. If the radio is to be used in a rural area, sensitivity, selectivity, and good noise characteristics, are more important. If the radio is primarily used on outings to the beach or on picnics, battery life, reliability, and ruggedness of the case and internal components are primary concerns. 

I think the RFG20 series probably was among the better "more bang for the buck" portable radios for the city dweller that was interested in pleasing appearance, good reception of local or regional stations at very low cost, and long battery life. The low battery voltage (3 volts) and low cost (less than $10.00, I believe) placed limitations on sensitivity and some other parameters that would be important in other situations, but, the radio provided good performance otherwise. The RFG20 would not be a good choice for someone located in a remote area trying to pull in distant stations.

For someone wanting a multi-band radio, the RCA "Strato-World" model with a total of 6 bands, including longwave, shortwave, AM, and FM might be a good choice, but at a cost of $99.95 one paid dearly (remember this was the 1960s) for the extra bands. Often when a radio includes many bands, the performance of the individual bands is not as good as it would be on a single band model due to cost and size constraints. A person primarily wanting excellent short wave performance might get more "bang for the buck" getting a good shortwave-only receiver, and buying a separate low cost radio for the other bands. 

In summary, I think the radio that provides the "best bang for the buck" depends more on how and where the radio is to be used and the characteristics the individual is looking for than anything else. In my opinion, all of the RCA portable radios provided good value for the cost, but each stressed different performance and styling characteristics. 

S: What were your first and last radio projects at RCA? 

D: My first radio design was an AM portable radio (model # RFG20). It was a low cost radio with average performance. One of it's most popular features was that it used only two "D" batteries, which would operate the radio well over 200 hours at normal volume before the batteries had to be replaced.

The last radio series I was involved with that went into production was the C/COS line of component and console products that RCA produced in the early 1970s. I was about halfway finished with a new AM/FM Stereo/Phono combination product when a corporate decision was made to eliminate the Audio Products Division I was in, and have all radio products designed overseas. Obviously that product did not go into production, as such, but it may have served as a starting point for the next Japanese design.

S: Was there any scheme to the model numbering used by RCA for its radios?

D: There were apparently variations on the model number schemes used by RCA. The portable radios I designed had a model number that started with three letters followed by a number and then another letter. The first letter was an "R," which indicated it was a radio product. The second letter indicated the year the radio was either designed or first appeared in the product line. I can't recall what the third letter indicated unless it differentiated between portables, table models, consoles, etc. The number indicated the specific model. The final letter indicated the color or case style.

A portable radio (model # 4RG6) designed by one of my coworkers did not strictly conform to the numbering scheme described above. It does seem that the two letters indicating the type product and the year, (RG) in the above model number, was consistent with that system.

Still other RCA model numbers of that period didn't seem to follow either of those schemes.

S: What have you done since leaving RCA?  Are you a ham radio operator, or do you keep your hand in "the trade" in any other way?

D: After leaving RCA I went to Electra Company where I was the design engineer on several of the Bearcat line of police scanners. When that company was sold to Uniden, a Japanese company, I took a position of senior engineer at The Naval Avionics Center, which was later renamed Naval Air Warfare Systems, Aircraft Division, Indianapolis (NAWC/ADI). While there I designed portions of electronic communications systems for military aircraft and weapon systems. It was a US government owned facility, and was sold to Hughes Electronics in 1997 after congress passed a military base closing bill. Although NAWC/ADI  was not a military base, it fell under the same classification in the bill. All the engineers were offered the same position at the same salary, benefits, and seniority with Hughes, but I was very near retirement age, and decided to retire. Hughes has since sold the company to Raytheon.

I have never had the slightest interest in ham radio. Although I occasionally read some technical books and articles, for the most part I pursue other interests now. 


Mr. Diamond provided interesting supplemental material, which can be viewed here.
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 Copyright 2002 By Sarah Lowrey. All Rights Reserved. Last updated May 18th, 2002.