Discrepancy Sheet

Found in the Attic: Heath BC-1A AM tuner

Posted by Tom Vernon on January 28, 2015

Heath BC-1AThe debate about high-quality AM signals vs. adjacent channel interference and occupied bandwidth has been going on longer than most of us have been alive. One of the sticking points was always the issue of 'who goes first?' Station engineers were reluctant to spend the time, money and energy to perfect their signal, only to have it trashed by receivers with misaligned 5 Khz IF stages and a 3-inch speaker. Receiver manufacturers, on the other hand, didn't want to build high-fidelity AM radios when most of the stations sounded like crap anyway.

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Topics: Vintage Electronics

Suitcase Radio: Zenith Portable Receiver

Posted by Tom Vernon on October 28, 2014

Zenith PortableOne of the great things about radio is its portability. Take it to the beach, in your boat, on a train. Take it just about anywhere. What's changed over the years is how easy it is to do that. Nowadays we take the portability of radio for granted, as we stuff a smart phone with a built-in FM tuner in our pocket and head out the door. It wasn't always that easy. This month's Found in the Attic examines suitcase radios, in particular the Zenith 6G601D Universal.

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Topics: Vintage Electronics

For these Radio Pros, Amateur Radio Offers Enjoyment

Posted by Dave Sarkies on August 20, 2014

Ham Operator ParkingIt’s no surprise that many broadcast engineers are also amateur radio enthusiasts. The concept of sending out a signal and communicating with people around the globe combined with the ability to tinker with gear and tweak that signal makes for an exciting mix for radio technicians, electrical engineers and others the world over.

It may also come as no surprise that we’ve got a few amateur radio operators within the ranks of The Telos Alliance. Chief Science Officer Greg Shay, KD8WLN, Telos Systems Vice President Kirk Harnack, KD5FYD and Support Specialist Ted Alexander, W8IXY are proud to be ‘hams,’ and each has a unique perspective on the hobby.

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Topics: Amateur Radio

Found in the Attic: Sencore DVM-56A Microranger

Posted by Tom Vernon on July 30, 2014

Sencore DVM 56-AA better title for this month's technical missive might be "Found on the Workbench", because that's where this item has lived for the past 30 years. When it was introduced in the early 1980s, the Sencore DVM-56 was a milestone device. It was one of the first DVMs to feature autoranging, thanks to the marriage of voltmeter and microprocessor technologies. No more constant fiddling with the range switch, remembering units of measurement, or where the decimal point goes. Other nice features were a programmable dB function, peak-to-peak, average and true RMS AC ranges, peak and null indicators and switch-selectable resolution of 3, 4 or 4 ½ digits. Resistances could be measured up to the unheard of range of 100 megohms and greater by paralleling a 90 meg resistor across the input terminals and using the Hi Power Ohms function.

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Topics: Vintage Radio Technology

Found in the Attic: GE BM-1-A FM monitor

Posted by Tom Vernon on July 16, 2014

GE FM monitorDuring the golden age of radio, all of America's largest electronics manufacturers were engaged, as there was lots of money and prestige to be had building broadcast equipment. RCA, Raytheon, Westinghouse and General Electric were all big players. By the 1960s, the AM and FM expansions were pretty much over. One by one, these big firms got out of broadcasting, often to pursue more lucrative government contracts as the war in Vietnam escalated.

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Topics: Vintage Radio Technology