McKay-Dymek Models AM3, AM5, and AM7 ==================================== In the 1970's and early 80's, McKay-Dymek made solid state AM tuners and general coverage LW/MW/SW receivers. They all had excellent audio fidelity. Of most interest is their line of analog-tuning AM tuners: the AM3, AM5, and AM7. They were used by many radio stations to monitor their broadcasts for audio quality. It is unknown how the AM3 compares to the AM5. The AM7 is similar to the AM5 except that it has an added longwave band. Here's some information from an eBay auction of a McKay-Dymek AM7 ----------------------------------------------------------------- "The AM7 tuner is basically a AM5 with the addition of the long wave band. Used in Europe. That you can receive along the east and west coast of the US. (See Information Below) Long Wave Information: "155 to 281 kHz: This is another AM broadcasting band in Europe and parts of Asia. In Europe, there are numerous high powered (1,000,000 watts or more) stations here. These stations are capable of covering an entire European nation like France or Germany with reliable signals around the clock. Although ionospheric propagation is not good at these frequencies, the high powers used means that many of these broadcasters can be heard along the Atlantic seaboard during the fall and winter. Best reception is usually from local sunset to about 0600 UTC. A few long wave stations in Asiatic Russia can be heard on the Pacific Coast beginning an hour or so before local sunrise." A Detroit Michigan user said: "I have an AM-7 and a DA-7. They make a nice pair together. Unfortunately, there's not too much long wave possible except on a few winter nights when I can pick up some of the powerhouses from Europe on the AM-7. I have heard Morocco, France, and BBC on longwave here in Detroit. In fact, this winter, I got them pretty regularly" Specifications: * Two Band High Fidelity Solid State Tuner * Frequency Range: 540-1605 kHz. Standard AM broadcast band,150-300 kHz Long Wave * Sensitivity: 6.0 ,uV for 10 dB signal to noise ratio on Long Wave Band. 3.0 uV for 10 dB signal to noise ratio on Standard AM broadcast band. * AGC Characteristic: Less than 6 dB output variation for an input level change of 10,uV to 10 mV. * Bandwidth: -3 dB RF Narrow - 6 kHz; Wide - 15 kHz * I.F. Rejection: 45 dB * Audio Frequency Response: -3 dB @ 15 Hz, 7500 Hz * Audio Whistle Filter: 9 kHz * Distortion: 1 kHz @ 30% modulation: 0.5% 1 kHz @ 50% modulation -- 1.0%, 1 kHz @ 80% modulation - 1.5% (1 mv @ 1 MHz input, wide & distant mode). * Audio Output: Standard: 1V RMS- 5K output. * Shipping weight: 12 lbs. (5.5 Kg.) * Dimensions: 17-1/2" x 10" x 3-1/2" (43cm x 25cm x 9cm) Features The McKay Dymek AM 7 TUNER is an all solid state high fidelity AM/Long Wave tuner combining extremely low distortion with excellent sensitivity, selectivity, and a wide audio range. The AM 7 is compatible with professional studio equipment as well as high fidelity "home" sound systems. The low profile black and teak cabinetry makes the AM 7 an attractive addition to any system or decor. Broadcasters all over the country report excellent results using Dymek Equipment as low cost monitors. As one station executive wrote, after using the Dymek as the standard, "our signal was as close to 'FM on the AM band' as we could get". Reception from local or distant stations is assured by a choice of narrow or wide bandwidth selections at the front panel. To prevent an overload of the "frontend" that may be caused by strong local stations, an attenuator in the antenna circuit has been included. An illuminated, easy-to-read tuning meter aids in ease of tuning and is standard equipment on all Dymek tuners. Remarkable selectivity is achieved with two eleven element ceramic filters. A whistle filter eliminates most bothersome noise common to AM listening. Distortion is low and sensitivity helps pull in those distant stations; lets you take advantage of AM's natural long range capabilities - hear stations which were previously unlistenable. Wide and narrow bandwidth selectors assure optimum local and distant reception. Illuminated tuning meter. The Dymek outreach for perfection in AM reception has produced the Am 7. Unlike conventional AM tuners, the AM 7 allows full and accurate reproduction of transmitted program material. For the first time, AM reception is not limited by the receiving equipment The complete transmitted fidelity may now be fully enjoyed and appreciated. McKay Dymek is the leading producer of AM high fidelity receiving equipment. Authoritative hi fi magazines agree that the quality of AM reception provided by Dymek equipment is truly excellent. This fact is further established by the acceptance of our products by scores of AM broadcasting stations throughout the United States. Many stations use more than one Dymek tuner to monitor and insure their transmitted quality. For many years very high quality AM transmitters have been operating, but due to the mediocre performance of available AM receiving equipment, most high fidelity experts believed AM reception to be of inherently poor quality. It is truly a difficult challenge to design and manufacture a tuner capable of high quality AM reception. McKay Dymek engineers accepted this challenge and, after expending great effort, have succeeded in the design of the AM 7. The McKay Dymek AM 7 tuner is a precision, solid state AM instrument of the highest quality. Innovations have been engineered to provide: Very low distortion even at high modulation levels using a unique hot carrier biased diode detector. Extremely wide frequency response through the use of expensive ceramic filters. High sensitivity for reception of weak, distant stations. Once you have listened to AM radio on the AM 7, surely you will agree with our many satisfied customers: the AM 7 is a truly superior addition to any high fidelity system. RIF SECTION Dual antenna connectors are provided on the rear panel. An RCA type connector is provided for coaxial cable antenna systems. There is also a set of terminals for direct connection to a longwire antenna and external grounding. A Dymek AM 7 tuner represents the very best in AM/Long Wave listening. Note:This unit needs an external antenna to work I used a terk AM antenna with this unit and it worked well. I am also putting this antenna up for sale. Check for it on ebay. and will need a long wave antenna to receive long wave. Like a Mckay Dymek DA7 Antenna or a QUANTUM QX PRO LOOP. The following informative message was posted to Usenet ------------------------------------------------------ From: Ted Shireman (TEDELM@aol.com) Subject: Re: [Airwaves] Dymek AM5 -- need schematic Newsgroups: rec.radio.broadcasting Date: 2003-04-03 13:53:21 PST Sorry, can't help with the schematic but can tell you about McKay Dymek. I am a a boyhood friend of George McKay (W6WXG) who developed the AM-5 tuner with his Chief Engineer, Paul Metsker. I helped put out a promotional newspaper called the Dymek News in those days, and have a list of more than 80 stations using this tuner, including WGAR, Cleveland, in 1976. Among his other products were the DR22/33 series general coverage AM/LSB/USB digital communications receivers that covered 50 kHz to 29.7 mHz. Some of these are available on the used market but are considered very rare. He sold many of the rack mounted version to the South Korean Navy. All Dymek products were made in Southern California, USA! Unfortunately George has retired from the business and the name has been sold to a company in Oregon.