For AM Stereo Stand-Alone Decoder Owner's Manual, please click on this link. |
Today's Date... |
NEWS BULLETIN
FOR IMMEDIATE RELEASE
Welcome to the world of AM high fidelity and meduci wideband AM stereo sound, day and night. The future of radio is now. Better reception. Better sound.
We have adopted Motorola's C-QuAM™ analog stereo AM technology, and are proud to offer the latest integrated circuit decoder technology available for C-QUAM™ stereo tuners, to provide optimum and accurate AM stereo performance. We re-launched AM Stereo in October 2005, and we gave C-QuAM™ a second chance in the marketplace by introducing three new AM stereo products since then.
These AM stereo products cannot economically be purchased anywhere else. There are many AM medium-wave stations broadcasting wideband full fidelity sound in different parts of the world. When received using an appropriate wide band high fidelity AM stereo receiver or tuner under good conditions in the reception environment, using a good external indoor tunable loop antenna, the recovered noise-free high definition sound is virtually indistinguishable from many FM stereo broadcasts! Hearing is believing! Sample one of our high definition AM stereo products, and judge the enhanced audio fidelity for yourself.
MEDUCI AM STEREO STAND-ALONE OUTBOARD DECODER IS READY TO CONVERT YOUR OWN AM HIGH FIDELITY RECEIVER TO C-QuAM STEREO!!
This high-quality and low-cost add-on AM stereo decoder printed circuit board circuitry is assembled and tested (not a kit!), and is based upon the popular third-generation Motorola MC13028AD stereo decoder chip. This 2.0" x 1.5" sized board will easily and economically convert your own tired sounding AM mono digital-tuned (ETR) receiver to stereo reception (where available) using the C-QuAM standard. This board accepts the signal from the I.F of a receiver (450 or 455 kHz) and decodes stereo medium wave broadcasts. It operates at 10-15 Volts D.C and provides standard line level left and right audio outputs, for direct connection to the receiver's audio amplifier. It may be used to support 30Hz to 15kHz audio, however this will depend on the bandwidth of your receiver's I.F strip. Instructions are included for typical installation to receivers. We provide free technical guidance and installation instructions with every order! We want you to succeed.
Assembled and tested decoder board:This is a stocked item, and is available for immediate shipment after your PayPal payment clears. This decoder is new and directly sold from the manufacturer. Assembled in the United States of America from U.S and globally-sourced parts.
For AM Stereo Stand-Alone Decoder Owner's Manual, please click on this link.
DELCO AUTOMOTIVE AM MONO/FM STEREO RADIO WAS CONVERTED TO AM STEREO!
Todd (WD4NGG) converted his Delco radio to AM stereo using the meduci AM_ST decoder, so that he could hear "The Mighty 1630 KCJJ" at night in stereo. He also receives WLS from Chicago! He added the forced mono switch to one of the mounting ears of the Delco radio! He placed the AM_ST board in a plastic box and added front-mounted AM Stereo indicator. This was a simple modification, since the I.F level from the Delco is an ideal match to the AM_ST board! Please send us your conversion pictures!
THE WORLD'S NEWEST AM STEREO BROADCASTER IS WOAP IN OWOSSO, MICHIGAN!
(((( NOW IN STEREO WHERE AVAILABLE ))))
We received a very nice note from Tony Burkhead (Operations Manager/Co-Owner at Modulation Media Group) on Wednesday, February 8th confirming that WOAP(AM) is now broadcasting BIG oldies stereo music from their huge tower in Owosso, Michigan USA. WOAP has a very wide listening range, serving Owosso, Corunna, Shiawassee County, and approximately 475,000 potential listeners. If you love oldies music from the 1950's through the 1970's, and especially the hard to find album cuts, you will be crazy about The Big 1080!
According to reception reports -- from Lansing, Grand Rapids, Saginaw, and Flint, to other Michigan cities -- they have not lost any coverage and signal strength since the stereo signal was launched! They conducted a two-week test to prove it.
You can also stream in stereo world-wide at Michigan's BIG Oldies. Their full program schedule is also on display.
Congratulations Tony on your successful launch of the world's newest AM stereo station! Thank you for sharing this fantastic grand news! Your music format is ideal for AM stereo.
AUSTRALIA's 2CA HAS RETURNED ANALOG STEREO TO THEIR LISTENERS!
After the nearly one year C-QuAM stereo absence on 2CA, that coincidentally occurred with their DAB+ digital stereo launch, 2CA is now airing their "Forever Classic" music format in both analog stereo and DAB+ digital stereo formats. 2CA can be heard at 1053 kHz in Canberra, Australian Capital Territory. When contacted in April 2011, station management said that the reversion to mono was due to technical reasons, and not from a policy decision to permanently drop AM stereo. Immediately after 2CA discontinued C-QuAM stereo, there were many unhappy listeners, that made their comments known on the station discussion boards. These regular listeners regretted the ceasure of broadcasting in C-QuAM stereo on the medium wave AM band -- they vowed to record air checks from their analog AM stereo radios if 2CA ever returned to AM stereo. Their wishes have been heard from station management! You can also listen via live stereo webstream world-wide at 1053-2CA-Forever Classic.
MEDUCI PRO1k TUNER WAS INCLUDED AS PART OF THE ROBB RADIO SHOW AND "The Mighty 1630 KCJJ" AM STEREO BROADCAST
Courtesy of Colonel Tab Patterson, Robb Spewak, Captain Steve Bridges, and KCJJ-AM, listen to the "Robb Radio" show recorded live from Coralville, Iowa USA. This was a four-hour music program that originally aired on November 5th, 2010. Tab used his meduci PRO1k tuner approximately seven miles from the KCJJ transmitter location to receive the show in full C-QuAM stereo with very wide stereo separation being evident. You can download the entire show at once, or get it in one-hour time blocks:
Robb_Radio_Show_110510This direct off-air recording from Stereo 1630 KCJJ demonstrates how well analog AM stereo rules, and shows the potential for C-QuAM stereo fidelity. This is despite NRSC-2, and the other restrictions being placed on the transmission technology. To hear the entire 201-minute show (provided that you have a robust Internet Service Provider capable of uninterrupted downloads), you can save the entire MP3 clip from this link:
robb_radio_20101105_entire_TRSS_November5_2010_CQuAM (378MB)Robb Spewak enjoyed spinning the records live in the KCJJ studio. Music selection ranged from the Beach Boys, the Offspring, Jerry Reed, the Moody Blues, to Bad Company, and other musical groups ... there was true variety, keeping in line with the KCJJ format. You may remember Robb as the third wheel on the "Don & Mike" show for many years. Now he is heard weekly on KCJJ.
TAB PATTERSON RE-VISITED KCJJ-AM WITH A FIRST-EVER HISTORIC QUADRAPHONIC RADIO BROADCAST CAPTURED USING HIS MEDUCI PRO1k TUNER!!
On April 14th 2011, Tab Patterson again visited Stereo 1630 KCJJ in Coralville, Iowa USA and made radio history with his successful Quadraphonic Radio test over C-QuAM stereo technology! This was a 12-minute long experimental broadcast to see if Quadraphonic Sound could be encoded, transmitted, received via the PRO1k, and successfully decoded (using Dolby Pro-Logic II) back into true Quadraphonic Sound, and four discrete audio channels, using conventional AM analog broadcasting technology. This video contains the direct over-the-air recording of KCJJ -- during the Robb Spewak show. This video also demonstrates how good AM stereo can sound, with very wide separation, and very low total harmonic distortion being present! To properly play this video, connect your computer to a Dolby Pro-Logic receiver and set the decoder to the "music mode." You should hear very defined vocals and musical instruments move throughout all four speakers. This proves that it is possible to get surround sound using an AM radio signal. First click on this link to be taken to another web page to listen to the Quadraphonic broadcast:
Robb_Radio_Show_Quadraphonic_MP3Tab was roughly seven miles from the KCJJ transmitter (actually in back of their on-air studios on Quarry Road) inside his pickup truck, using his PRO1k with his TERK Technologies Audiovox AM Advantage 1000 passive antenna), which he had placed on the roof of his truck. It was windy that day, and the antenna was rocking back and forth. As the antenna moved in the wind, the antenna patch cable briefly lost contact with the Terk's 1/8-inch connector jack. This caused the received C-QuAM signal to briefly lose stereo lock twice during the recording. Tab believes that the studio structure actually helped block the adjacent AM iBiquity HD Radio station on 1600kHz from interfering with the historic Quadra-cast sound broadcast on 1630 kHz. Two of the three songs were directly played from quadraphonic 8-Track tapes in the KCJJ studio. The song from Chicago was encoded using the Rhino DVD surround sound release of the original Quadraphonic album. This is really pushing C-QuAM technology to its limits because the audio phasing has to be perfect! We hope the listeners enjoyed this Robb Radio Show special treat! Perhaps you were lucky to hear it live OFF-AIR from KCJJ using your Dolby Pro-Logic home audio system receiver modified with an AM stereo decoder!?!
Due to your e-mail requests, we now offer Tab's full 12-minute audio file (16-bit WAV sound format) that you can download to your audio file collection! This WAV file does not make use of any digital audio compression or resulting artifacts, therefore it is a large file. To save the file to your computer, you first right click on the file name called "KCJJ_Quadtest_PRO1K" below, then (depending on the functionality of your web browser), select "Save Target As..." then choose your destination for the audio file to be saved, then (depending on your ISP connection speed) grab a cup of coffee (or several cups):
KCJJ_Quadtest_PRO1K (132MB)Please note that you will not be able to stream this file from this web site. You should be able to save the file to your computer following the above instructions!
LISTEN TO WATV(AM) IN BIRMINGHAM, ALABAMA -- TRANSMITTING KAHN ISB AM STEREO -- IN DECEMBER 1982 (A MEDUCI WEB SITE EXCLUSIVE)!
With great pride, courtesy of Joe Dentici, who was the Chief Engineer for full-power WATV(AM) in 1982, you can enjoy approximately 31 minutes of AM stereo music using the Kahn-Hazeltine (ISB) format. This exclusive high quality recording was produced without the NRSC-1 and RF mask limitations currently being placed on AM radio technology within the United States. Audio was 'flat' from the AM stereo transmitter to the Sansui AM stereo receiver, without any audio pre-emphasis and de-emphasis curves being introduced into the process. This is an excellent example of how well AM sounded "back in the day" when the stereo format wars were being battled nationwide. This audio recording was completed in December of 1982, directly recorded from Joe's Sansui AM Stereo receiver (decoded using the Kahn ISB format) off-air from WATV(AM), into one vintage Ampex 601-2 tape recorder, then (finally) to compact disk recorder. Joe said, "There is no coloring of the tapes or of the CD."
Joe wanted to make a difference in the radio broadcast industry, to give to the public a radio station that "sounded like their high fidelity sound system, and not like their radio." Joe built the entire transmission chain: the transmitter was a CCA AM-1000D ("I loved that rig because it was built right and was all tube"), and the audio processing was from two Dorrough DAP 310's ("Mike Dorrough and I are the best of friends, and to this day, I have not seen or heard a better or more natural sounding units than those were"). The feed to the transmitter was from two 15kHz equalized lines, that Joe ensured were as close to flat as could be done. The studio employed one Collins IC-10 Console, ITC cart machines, QRK turntables, and RCA 77DX microphone. Joe said, "Remember that we were not limited in audio response or any RF filters forced on AM stations today. The quality you will hear is what real engineering is all about." And so, without further delay, this is the audio aircheck file:
WATV_900kHz_Kahn_Dec1982 (73MB)To save the file to your computer, you first right click on the file name called "WATV_Kahn_Dec1982" above, then (depending on the functionality of your web browser), select "Save Target As..." then choose your destination for the audio file to be saved. Please note that you will not be able to stream this file from this web site. You should be able to save the file to your computer following the above instructions!
WATV(AM) still has AM stereo broadcasts, now using the Motorola C-QuAM format. Sadly, Joe Dentici lost his battle with leukemia on June 29, 2006. I enjoyed our past conversations about his vast technical history in broadcasting. These pages are dedicated to the memory of Joe. He enjoyed listening to his meduci AMX2000 tuner. May he rest in peace.
NEW DIGITAL TUNER WILL BE MADE AVAILABLE FROM MEDUCI
In 2006, we developed prototype meduci AM stereo tuner for two Chicago AM stations that included the following features:
Our newest tuner has all of the above features, as well as the following additional new features:
Balanced audio outputs with XLR male connectors provide uncompromising audio performance for critical listening applications with compatible audio components.
Each tuner is frequency agile, with drift-free quartz crystal phase lock loop accuracy (down to better than 100 ppm stability). Each tuner is set to the station's frequency, based upon internal DIP switch selection.
Loss-of-carrier signal sense (open collector) is also standard, to interface to user-supplied alarm device. Each tuner can be mounted to standard EIA 19" relay rack. Antenna input is 50 ohm BNC connection. Purchaser can also specify either XLR, Euroblock, or 1/4" TRS audio outputs.
Designed as a general purpose off-air AM monitor demodulator grade receiver for EAS or other critical applications.
Each tuner will be priced according to market conditions. There is an approximate four-week manufacturing lead time.
Analog AM stereo technology has claimed its roots almost since the beginning of conventional monaural AM broadcasting within the United States. Later, four different competing AM stereo systems were placed on the air in the early 1980's, including systems from Motorola (C-QuAM™), Magnavox (PMX), Kahn-Hazeltine (ISB), and Harris Broadcast (Variable Angle Compatible Phase Multiplex, or V-CPM). Eventually in 1993, Motorola's C-QuAM technology achieved the exclusive standard for AM stereo broadcasting within the U.S.A. During this time period, Australia, Japan, and other countries were also exclusively using the Motorola C-QuAM system, making C-QuAM the essential de facto world standard for AM stereo broadcasting technology.
All of the AM stereo systems share in common the addition of a stereo exciter to the existing monaural AM transmitter. This exciter typically has two outputs: the monaural L+R audio, which is time delayed and fed to the transmitter's normal audio input; the second output is the R.F carrier, which replaces the signal from the transmitter's normal quartz crystal oscillator stage. This signal also contains the necessary time delayed and phase modulated (quadrature) information. Because these stereo exciters are retrofitted onto transmitters which were never designed for AM stereo operation, they also must contain corrective equalizers and adjustable delay networks, to insure that all of the relationships are correct through the transmitter modulator, power amplifier, and ATU/antenna system. Decoded stereo separation suffers if the timing and phase relationships are not correct at the receiver.
Motorola's C-QuAM system is covered in several U.S. patents written by Frank H. Hilbert and the late Norman W. Parker of Illinois. Norman Parker invented the C-QuAM system, per written correspondence from his wife, Margaret Parker. Margaret also wrote all of the patents. Patent number 4,218,586 was applicable to the basic system. Other patents included 4,406,922 and 4,192,968. Delco Electronics Corporation (now known as Delphi) later introduced many adaptations and new C-QuAM inventions, covered under various additional U.S patents.
It is with great sadness that we report the passing of Edwin Buterbaugh (pronounced Boo-ter-baw), on September 1, 2008 from a four-year bout with bladder cancer. Ed was 65 years old, and longtime Director of Engineering at WJR(AM) in Detroit, Michigan, USA. Ed was directly responsible for maintaining the legendary AM stereo sound heard at WJR(AM). Ed completely rebuilt the WJR studios twice, once in 1987, and again in 2001. He was instrumental in ensuring that all WJR(AM) remote live broadcasts were transmitted in stereo, including the annual Thanksgiving Day parade on Woodward Avenue in Detroit. On a personal note, it was absolutely awesome to listen to the many Detroit Tigers baseball and Red Wings hockey live broadcasts in stereo, as well as the Thanksgiving Day parade event. Many were received 200 miles in full stereo from the transmitter. It was not easy for WJR's engineering team to capture the crowd noises, ambience, press box, and other sounds, backhaul it from downtown Detroit to Riverview's transmitter site, and then transmit it on WJR(AM), the 50kW high power "The Great Voice of the Great Lakes" radio station. For those who were able to hear those historical AM stereo broadcasts, it was as if you were there at the stadium, directly in the middle of the action! It was also during Ed's tenure, that their Motorola C-QuAM stereo generator was overhauled, and all of the electrolytic capacitors were replaced within the unit. As a listener to WJR's AM stereo sound almost since the beginning, until its end on October 26, 2005, I know that Ed was very proud of the wide stereo separation and lightly processed air chain that he engineered. Ed's passion for quality AM stereo sound will be missed! There are not many chief engineers like him that share that passion. Mike Fezzey, WJR's President and General Manager, says, "Ed has led us through rebuilds, build-outs, blackouts, uplinks, downlinks, installs, re-installs, AM stereo, transmitter installations, digital conversion and more." Ed retired from WJR(AM) in 2004 after 20 years. WJR's Creative Director John Marshall reflects back on Ed's life. You can listen now by clicking here! 
Prior to arriving at WJR(AM), Ed engineered the signature sound for 13 years at CKLW(AM) "The Big 8" (Windsor, Ontario) in its heyday as a 50kW Top-40 popular music station powerhouse. CKLW(AM) could be heard in four Canadian provinces and 28 United States at night. During the day, CKLW(AM) also could be received in five states (Michigan, Ohio, Indiana, Pennsylvania, and New York)! Ed was responsible for the booming midrange-heavy music heard from many portable transistor radios of that era. One day at CKLW, Ed decided to remove the coupling capacitors (in order to likely improve the low bass frequency response), and accidently reduced CKLW's output power to 25kW! He later realized that removing the coupling capacitors allowed DC voltage to ride on top of the audio into the transmitter's modulator stage. This DC voltage shift caused the voltage bias of the transmitter to change, resulting in the reduced power output. Ed said that it could have been worse, had the voltage went towards the other direction, causing the transmitter output to exceed 50kW. Ed was also responsible in 1979 for testing the Harris V-CPM AM stereo system at CKLW(AM). Ed produced a 52-page report detailing his direct findings from the tests. It covered channel separation (as affected by directional antenna systems), adjacent channel interference, directional antenna null protection, distortion in monaural receivers, skywave effects, compatibility, frequency response, distortion, and signal-to-noise ratio.
It was our love of AM stereo that prompted us to attempt to listen to WJR(AM) stereo in November 1982 using the "two radio" trick. We did not hear any stereo separation, though the recovered sound was definitely phased in different directions from the two radios. WJR(AM) was a heritage station and class act that truly believed in the C-QuAM technology. There was a definite commitment from WJR(AM) to transmit good high quality stereo sound to their listeners. Stereo programing included the weekend music magazines Kaleidoscope and Patterns In Music, which focused on various music genres, themes, and eras, hosted by Mike Whorf. WJR(AM) was one of the few C-QuAM stereo pioneer stations. And those many stereo remote live broadcasts were not easy to put together. Ed's commitment to quality sound inspired us to research, develop, engineer, and to introduce the first AMX2000 stereo tuner in mid-2005. All of our AMX2000 tuners are now dedicated to the memory of Ed Buterbaugh, for your many engineering contributions at WJR(AM).
meduci, LLC is a highly entrepreneurial and innovative organization that specializes in custom free-lance engineering, research, design, and production of electronic products in prototype quantities up to large scale manufacturing. We also design low frequency (class A, class AB, class D) audio power amplifiers, class C power R.F amplifiers, and R.F front-end (amplifier, mixer, oscillator), using National Semiconductor, Motorola, and other custom ASIC chipsets and discrete components. We strive for quality and excellence in workmanship. Our products are designed for faithful sonic reproduction of the on-air source material. For customers with specific requirements, you could always count on us to produce innovative solutions. Our customers are benefited by better pricing, quality warranty, and excellent technical support. Contact us for a free quotation -- we appreciate your business. Our goal is to meet the needs of our buyers, distributors and dealers, and we can work on an ad hoc basis.
Access statistics provided by 