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Blog Central

Found in the Attic: Heathkit GR-81 Economy Short Wave Radio

Posted by Tom Vernon on Jan 9, 2017 10:00:00 AM

An ancient Chinese proverb says, “The longest journey begins with the first step.” And so it is with building Heathkits. Over the years, I've assembled countless Heathkit projects, most for personal use, some for the electronics workbench at college media centers and radio stations, and a few as gifts. But you never forget your very first one. When I made my most recent trip to the attic, I came down with numero uno, my first electronics kit, a Heath GR-81 economy short wave radio. This three-tube, four-band receiver covered 140 Khz to 18 Mhz. The GR-81 had a long production run, from 1961-1972. List price in the 1967 catalog was $23.50. The estimated time for completion was about six hours.

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Topics: Vintage Radio Technology, Vintage Electronics

Found in the Attic: NuTone 2067B-2068B Transistor Radio-Intercom System

Posted by Tom Vernon on May 24, 2016 4:00:00 PM

Radios come in all shapes and sizes, and this column seeks out some of the forgotten and unusual examples. Previous installments have examined farm radios, unlikely portables and early clock radios. This time around, we'll look at the NuTone 2067B transistor radio intercom system. It dates to 1965, when home radio-intercoms were something of a status symbol in larger houses.

These systems enabled users to play music through any or all of the up to ten intercom stations throughout the house. In addition to the AM-FM radio, records or tapes could be played via the external input jack. The intercom portion enabled room-to-room communication, plus the ability to answer the door, if there was an outdoor intercom station. Also, the home intercom could be connected to a NuTone doorbell chime, so the chimes could be audible through the intercom stations.

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Topics: Vintage Radio Technology, Vintage Electronics

Found in the Attic: Wollensak 1500 Series Tape Recorders

Posted by Tom Vernon on May 19, 2016 4:29:00 PM

Anyone who worked for the high school AV club or college media services department in the late ‘60s or 1970s remembers the Wollensak 1500 series reel-to-reel recorders. Along with the RCA hand-threaded 16 mm projectors, they were the bread and butter of instructional media. The hallmark of these devices was their ease of use and indestructible design. Get ready for a flashback to your adolescence, when all you needed to know about tape recorders was 'PLAY-RECORD-STOP', as we peer beneath that white and chrome exterior of Wollensak 1500 tape recorders.

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Topics: Vintage Radio Technology

Found in the Attic: 1920s Radio Workshop

Posted by Tom Vernon on Apr 26, 2016 11:30:00 PM

As electronics technology has evolved over the years, so has the equipment used to service it. Today, electronics is largely a software game, where DSP chips take the place of tuned RF circuits, and even complete receivers. These devices operate with specs near theoretical perfection. As a result, the workbench is no longer the nerve center of an engineering shop in the way that it once was.

The electronics workbench had its origins around the same time as radio, in the mid-1920s. Those old TRF sets could be unreliable, and anyone who sold radios as a business also installed and serviced them. This installment of Found in the Attic is a bit different. We'll dig out several items that were essential for radio servicing in the 1920s, as we imagine what types of things were on the electronics workbench almost 100 years ago.

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Topics: Vintage Radio Technology

Found in the Attic: The Sta-Level Turns 60

Posted by Tom Vernon on Mar 28, 2016 11:30:00 PM

As a teenager coming of age in the late '60s and early '70s, I went on nickel tours of every radio station I could. Some of them twice. One piece of equipment that almost every station had was a Gates Sta-Level AGC amplifier. It's safe to say that this device dominated the sound of Top 40 radio from the 1960s through the early '70s. Introduced sixty years ago, in 1956, Gates sold them by the boatload.

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Topics: Vintage Radio Technology

Found in the Attic: MSI CP-803 Composite Processor

Posted by Tom Vernon on Mar 2, 2016 4:51:25 PM

The first AGC and peak limiter amps for broadcast audio were designed to maintain a station's modulation within FCC limits. Starting in the mid-1960s, they evolved into tools to create a unique 'sound', and to win loudness wars. By 1980, it seemed that audio had been squeezed and squashed as much as possible, and listener fatigue was a common topic for articles and discussions. Then, the composite processor appeared on the scene, and new heights of loudness seemed possible for FM broadcasters. This installment of Found in the Attic contains a brief history of composite processors, and discusses the Modulation Sciences Inc. CP-803 in particular.

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Topics: Vintage Radio Technology

Found in the Attic: Broadcast Electronics 500

Posted by Tom Vernon on Jan 26, 2016 3:34:26 PM

An earlier installment of Found in the Attic looked at the ATC/Collins P-190 cart machine, which was the first commercially available tape cartridge deck, and the hit of the show at NAB '59. Around that time, Ross Beville, Chief Engineer of WWDC in Washington, DC had the same idea, and also began to develop tape cartridge machines. He apparently did not know about the work of ATC's Bailey and Jenkins until NAB '59. In June of 1959, Beville founded Broadcast Electronics in Silver Springs, MD, to manufacture Spotmaster cart machines. The first production runs were built in the station's garage.

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Topics: Vintage Radio Technology

Found in the Attic: RF Test Twofer

Posted by Tom Vernon on Dec 28, 2015 2:19:05 PM

It's hard to believe in this day of digital technology and broadband RF strips, but at one time a solid understanding of tuned RF circuits was an essential part of electronics troubleshooting, as well as to getting your FCC First Class License. Today, the grid-dip meter is all but forgotten, but it was, and still is, an essential item in the RF engineer's toolbox. This Found in the Attic is another twofer, and looks at both the Millen 90651 Grid-Dip Meter and Heathkit HD-1250 solid-state dip meter.

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Topics: Vintage Radio Technology

The Birth of a Flamethrower!!

Posted by Frank Foti on Nov 11, 2015 2:15:00 PM

Back when I was in grade school (a time long before electricity), the tallest building in the world was the Empire State Building in New York City. The majesty of that building has always held a special place in my heart; that’s why, in the summer of 1983, it was even more special that I got involved with a project that was to add a twelfth FM radio station to Master FM Antenna System at Empire.

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Topics: Vintage Radio Technology

Found in the Attic: Zenith Royal 1000 TransOceanic

Posted by Tom Vernon on Oct 5, 2015 12:49:00 PM

The lure of snagging distant short wave signals from the other side of the globe has been a part of radio listening from the earliest days. As receiver and battery technologies improved, radios became portable, meaning DXers were no longer confined to listening in their basement or attic radio shacks.

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Topics: Vintage Radio Technology