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Announcing the death of ugly AM radio sound!

Welcome to the world of AM high fidelity and meduci wideband AM stereo quality sound, day and night. The future of radio is now. Better reception. Better sound. At meduci, we are very passionate about good quality sound. meduci has AM stereo radios for sale.

Many radio manufacturers are leading you, the consumer, to believe that AM radio sound is literally abysmal! Radio manufacturers have, by cutting corners and costs, tossed aside a medium that can sound as good as FM radio broadcasting, and reach a farther listening area. In many communities, an AM station is the only LOCAL live media! It deeply angers meduci that public perception of what AM "sounds" like should be garbage, when in actuality- its potential goes far beyond what most people have ever heard! We hope that when you hear a good AM stereo station proudly speaking about their "sound" that you realize it is your current RADIO product that limits the quality of what you hear, not the AM band itself!

Our American economy is driven by purchases, and purchase price is certainly a determining factor. However, that DOES NOT mean that saving a few pennies here, or a dollar per unit there, to improve the quality of AM sound in radios, would break the manufacturer, or the consumer. This explains why we did not cut corners when designing and manufacturing our own AM stereo products.

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 four new AM stereo products since then. These AM stereo products cannot be purchased anywhere else. Customers are very satisfied with their meduci tuners. Satisfaction is so high that meduci tuners are not re-sold on eBay. Each meduci product is also backed with one-year warranty against defects in material and workmanship. We use ORIGINAL McCoy Motorola IC chips and other prime components in every meduci AM STEREO product.

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 high quality FM stereo broadcasts! Hearing is believing! Sample one of our high definition AM stereo products, and judge the enhanced audio fidelity for yourself.

model: AM_ST


This high-quality and low-cost add-on after-market AM stereo decoder printed circuit board is assembled and tested (not a kit!), and the circuitry is based upon the popular third-generation Motorola MC13028AD stereo decoder chip. For the do-it-yourself person, this 2.0 inch by 1.5 inch (50.8mm x 38.1mm) sized board will easily and economically convert your own tired sounding mono digital electronic tuned receiver (ETR) to stereo reception (where available) using the C-QuAM standard. This board accepts the signal from the Intermediate Frequency (I.F) of a receiver (450 or 455 kHz) and decodes stereo broadcasts. It operates at 10-15 Volts D.C and provides standard buffered and isolated line level left and right audio outputs, for direct connection to the receiver's audio amplifier. It may be used to support 30 Hertz to 15,000 Hertz audio frequency response; however, much of this will depend on the bandwidth of your receiver's I.F strip. Instructions are included for typical installation to receivers. BONUS: Forced Mono feature is included on-board. Schematic diagram and details are included with purchase. We also provide free technical guidance and installation instructions with every order! We want you to succeed.

free shipping to USA address destination.
Assembled and tested decoder board:
New price effective now: $28.00 USD each, to any PayPal confirmed shipping address virtually anywhere within the world, with zero additional cost for postage and handling to destinations inside the continental United States. Tuner/receiver is not included with your purchase. Please ensure prior to your purchase that there is adequate space inside your host receiver to be converted to AM stereo. There are six internal connections to be made to your receiver (+12-volt D.C power, ground, 450 or 455 kHz I.F input, stereo LED driver output, left channel audio output, and right channel audio output). If you wish to add forced mono switch, then seven connections are necessary. There is also an on-board small eight-volt linear-mode IC voltage regulator. Purchase details are located here>> meduci AM_ST STAND-ALONE OUTBOARD DECODER.

This is a stocked item, and is available for immediate shipment after your PayPal payment clears to our bank account (typically within three to five business days). This decoder is new, made-to-order, and is directly sold from the manufacturer. Assembled in the United States of America from U.S and globally-sourced parts.

For AM Stereo Stand-Alone AM_ST Decoder Owner's Manual, please click on this link.


  • Carver TX-2
  • C.Crane CC Radio-SW
  • Redsun RP2100
  • Kenwood TS-140S
  • J.C Penney MCS3050 (Model Number 683-3050 - Catalog Number 853-6641)
  • Delco 16194955
  • Sony STR-DE525
  • Marantz ST-6000
  • Marantz ST-6001
  • Teac T-H500
  • Sansui 5050
  • Pioneer TX-950


    In this corner, we will spotlight current projects for our meduci AM_ST outboard decoder! Mike G. from Hudsonville, Michigan successfully modified his Sony STR-DE525 receiver to hear WLS-AM (Chicago, Illinois USA) and WIRL-AM (Peoria, Illinois USA) in stereo at night!

    This picture shows the successful installation with AM_ST decoder mounted flat against the outside of the existing FM/AM tuner pack module inside Mike's Sony STR-DE525 receiver:

    Sony AM stereo installation

    There were five total new connections made inside the Sony tuner pack. This tuner use the Sanyo LA1837 which is an "AM stereo friendly" design, with easy left and right AM stereo audio connections back into this IC chip:

    Sony Connections It's a Sony

    Mike breaked the connection between pins 22 and 24 on LA1837 to disable the mono AM audio path. Also, this Sony receiver's micro-processor does not read the STEREO pin when tuner is placed on AM band. Therefore, the front panel stereo indicator would not properly indicate when AM stereo C-QuAM stations were received. Since this is the case, Mike was able to ingeniously use the receiver's front panel DVD/5.1 Dolby Surround LED indicator to indicate when this receiver was tuned to AM stereo stations. This indicator now serves duty as AM stereo, DVD, and 5.1 Dolby Surround indication. Mike made the connection on the printed circuit board behind the front panel:


    After this installation was completed, Mike says, "Well Jeff I got her to work!!! You were right about the stereo indicator light only working during FM operation. So found out that where I tapped the power it was dropping the voltage to about three volts so the decoder wouldn't work. Tap it to the tuner power and works great now. I used 15k-ohm series resistors for audio and sounds great. ... I appreciate the product and help."

    Mike is procuring parts to assemble his own home-made large tunable loop antenna in order to improve reception further from distant AM stereo stations.


    Sanyo Boombox Mod

    Sean Cuthbert installed his meduci AM_ST decoder board inside the Sanyo AM/FM/SW/cassette boombox radio with very good results. He found that second hand AM stereo radios are very expensive, as sold on eBay. To save money, Sean decided to convert his own radio to AM stereo reception. He likes this Sanyo model, as it has two shortwave reception bands. In order to improve the recovered audio bandwidth, Sean also replaced the AM medium wave ceramic filter with a better device, capable of 10kHz audio response. This compares to the stock ceramic filter that allowed the AM radio portion to reproduce audio up to 4kHz (essentially telephone line quality)! Also, an integrated cassette recorder facilitates AM stereo airchecks to be saved.

    playback button Play the video by clicking here>> AM stereo modification to Sanyo boombox.


    Neto Silva from Brazil installed his meduci AM_ST decoder into his J. C. Penney MCS-3050 tuner to improve the overall sound and to reduce audio distortion. Why would anyone add an AM stereo decoder to a tuner that already contains an AM stereo tuner? J.C Penney uses the Motorola first generation AM stereo decoder chip (MC13020P). In the third generation decoder chip (MC13028A) used in our AM_ST add-on board, a balanced full-wave envelope detector is used, which is technically better than the half-wave diode envelope detectors used in garden variety AM tuners and receivers. This design improves audio fidelity, due to the very low total harmonic distortion encountered (typically under one percent, and inaudible to the human ear)!

    MCS3050_Upgrade MCS3050_Upgrade2

    There were six connections made from the AM_ST decoder board to the MCS-3050 tuner board. Of course, meduci provided complete and detailed installation instructions with AM_ST decoder purchase! If you have MCS-3050 tuner, you should consider upgrading the AM stereo functionality with one of our AM_ST models.


    decoder inside decoder outside

    Rich Modafferi built his "connect to any radio" AM stereo decoder enclosure to house his meduci AM_ST decoder board, which complements his tube-based AM stereo C-QuAM transmitter. Rich also used his Sencore SG80 stereo generator for testing purposes. His enclosure has inputs for 455 kHz I.F and a level control is provided for adjusting this I.F input. There are both BNC and RCA I.F input jacks, and fixed and variable audio level outputs. Single indicator lamp functions for "power" and "stereo", glowing dim on power, and full bright for AM C-QuAM stereo lock.



    X-FM conducted C-QuAM stereo broadcast on July 23, 2012. Kenwood TS-140S shortwave receiver was modified by JFarley for AM stereo reception using his AM_ST decoder. This modification allowed reception for this X-FM underground test broadcast from Redhat using C-QuAM stereo technology! This unique "music to the power of X" broadcast signed on just after 02:00 UTC with test tones at various frequencies, then X-FM identification as "C-QuAM AM stereo test transmission" followed by The Cars "Moving in Stereo" song. Indeed, this is an appropriate song for this test! You can listen to this stereo broadcast here>> meduci AM STEREO SHORTWAVE TEST (20.2MB).

    XFM Test meduci close up

    There is some fading evident during the 43-meter single sideband shortwave test transmission. As expected, lack of stereo lock occurred during the very deep fades. From JFarley: "With the hardware decoder on a TS-140S, I have pilot about 50 percent of the time. Thought there was separation during The Cars piece when you got above S9. Kind of eerie listening and just getting a feel for this. It's noisy tonight with choppy fades. The meduci decoder in the TS-140S seems to lose pilot easily in a fade. I am in and out of lock with fading, and it is sometimes a pronounced difference, sometimes it is more subtle. But it is stereo! Reception here was around S8-S9, and that would have been enough to keep pilot lock here, I feel. Problem was the very choppy fades down to S5. I also noted some unlocking due to noise."

    You do not need to search high and low for a Kenwood TS-140S shortwave receiver. Our past customers have successfully combined Redsun RP2100 with our outboard AM_ST stereo C-QuAM decoder board with very good results. Redsun RP2100 is nearly identical to C.Crane CC Radio-SW model. Both models tune the entire shortwave radio bands, and have the necessary 455kHz I.F output, so you do not need to open the radio, in order to install our AM_ST model C-QuAM decoder board.


    Todd's First!

    Todd Roberts (WD4NGG) converted his Delco automotive FM stereo/AM mono radio (model 16194955 - readily available on eBay) to AM stereo using his meduci outboard AM_ST decoder, so that he could hear "The Mighty 1630 KCJJ" in stereo. He also receives WLS from Chicago via skywave propagation! 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. Todd also replaced the stock 3kHz ceramic filter in the Delco radio with new 7.5kHz ceramic filter from eBay. This was a simple modification, since the 450 kHz I.F level from the Delco is an ideal match to the AM_ST board!

    Since muRata 3.6MHz ceramic reonators are as scarce as hen's teeth these days, Todd used one 43uH toroid inductor resonated with a 9-50pFd ceramic trimmer in place of the stock ceramic resonator. With continued experimentation, Todd says, "One thing I noticed using the toroid with loose turns wound over the core was it seemed to be a bit microphonic if bumped, so the turns will need to be glued in place, and the toroid probably glued to the board, to make it rock solid. Of course there were no microphonics noticed when tapping the ceramic resonator."

    Todd's BUD Box

    Todd's most recent summer project was to relocate his meduci AM_ST outboard decoder into a small aluminum shielded BUD box enclosure, which was mounted to an aluminum sub-panel, then bolted to the front mounting ears on the top of his Delco 16194955 AM Mono/FM Stereo automotive radio.

    Todd's solution to interfacing the Delco's internal top tuning board to the outboard AM_ST decoder was to solder a printed circuit board-mounted SMA socket directly to the tuner board. This socket was connected across the output pin from the 7.5kHz ceramic filter, and its ground pin, without having to drill any holes, or change anything on the tuner board. Todd was then able to route the I.F signal from the Delco radio to his AM_ST decoder board using a small SMA shielded jumper cable and SMA connectors. Todd did have to punch out one 0.5-inch hole in the top cover of the Delco radio, in order to allow the SMA socket to protude through the top cover. Modifications were not necessary to the Delco tuner board itself, though.

    Using a spectrum analyzer, Todd determined that using this very short length of small SMA shielded cable did not affect the I.F filter's passband or ripple. This re-packaged combination also eliminated the stray shortwave station interference that Todd had previously encountered, sometimes when listening at night, when using his AM_ST decoder mounted in an unshielded plastic box.

    Hopefully, these modifications provides inspiration for project creations using your own meduci AM_ST decoder board. Please send us your AM stereo decoder conversion pictures, experiments, and descriptions using your AM_ST decoder! We will display the pictures and describe your project in an upcoming meduci web site update.



    We received e-mail on February 4th, 2013 from Jim Carlyle, owner of WION-AM, in Ionia, Michigan USA that "America's Biggest Little Radio Station" celebrated sixty years of broadcasting on February 1st, 2013 and launched full public streaming from their C-QuAM AM stereo tuner on the same day! Listeners can actually hear the high fidelity sound directly taken off-the-air from the local AM stereo broadcast! This is the actual "over the air" signal received in the famous WION studios! Jim says, "We chose to 'show off' what AM stereo can be in this stream, instead of selecting FM or a live 'board' the hopes people will notice the quality we offer, and know that AM in stereo can rival other broadcast means! Our goal is to be the BEST sounding AM stereo anywhere!" WION is full-service radio station, serving mid-Michigan with C-QuAM AM stereo! Enjoy their vast library of adult hits, classic rock music, and the occasional golden oldie! You can listen world-wide at>> WION AM STEREO. Jim, thank you for providing AM stereo music to your listeners and community, and here is to sixty more years of broadcasting! Congratulations on your successful launch for your AM stereo station! Thank you for sharing this fantastic grand news! Your music format is ideal for AM stereo.


    Todd's First! Todd's First!

    Brian Winnekins will be launching C-QuAM high fidelity stereo at WRDN(AM) in Durand, Wisconsin USA in coming weeks. Brian will be using CRL Systems AM Stereo gear. Brian received one Matrix Processor, two Spectral Energy Processors (one for each stereo channel), as well as Audio Preparation Processor, and Stereo Modulation Processor, all manufactured by CRL Systems. We are certain that WRDN listeners will rejoice in the streets!


    WCOR(AM) in Lebanon, Tennessee has returned AM stereo to their listeners. WCOR features the Real Country format, which blends the traditional sound from today's hottest new artists, with the great country music classics.

    This is a recording of WCOR(AM) in the early morning hours of January 12, 2014. WCOR is a class-C AM broadcast station located in Lebanon, Tennessee operating at 1,000 watts full time, non-directional day and night, and the tower is located approximately 29 miles east of Nashville, Tennessee USA. WCOR is owned by Bay-Pointe Broadcasting company, and broadcasts various community related programs, as well as locally produced shows on a daily basis. WCOR simulcasts sister station WANT(FM) for most of its broadcast day, and carries Cumulus Media's Real Country format. Programing differs in some day parts, usually to carry local sports programing.


    This air check was recorded using a Tascam DR-07 digital recorder in uncompressed PCM from a Sony SRF-A100 AM Stereo "micro boombox" portable radio. A great example of how great AM Stereo sounds starts at 16 minutes, but the entire recording sounds very good. This file is uploaded in uncompressed PCM. YouTube's processing does introduce some compression. Also, the Sony radio has a touch of distortion from the C-QuAM decoding process, so the distortion heard is due to the radio, and not from WCOR. With a wideband high fidelity AM tuner, it is very easy to hear how AM stations sound- with or without AM stereo- despite the current NRSC bandwidth limitations. Try getting that with digital HD Radio on the AM MW broadcast band, especially with the widespread use of Spectral Band Replication (or SBR), which is their best guess for how the high audio frequencies should be heard!

    How does WCOR transmit AM STEREO? Station engineering decided to activate the stereo encoder card that was designed and intended for use with their new modern Broadcast Electronics AM transmitter. Since WCOR has non-directional antenna pattern, simply utilizing one tower, it was very easy to launch the C-QuAM format with minimal tuning and other effort. Also, the air studio is wired for stereo, and nearly collocated with the AM transmitter, so an expensive studio-to-transmitter link was unnecessary. Try to give the station a listen one day or night from your AM stereo receiver or tuner! If you do not have an AM stereo tuner, then please contact meduci to remedy that situation!


    KYET(AM) in Kingman, Arizona signed on for the first time at 1170 kHz on October 14th, 2012. KYET is owned by broadcast veteran Joe Hart and Route 66 Broadcasting company. They have Harris DX-10 transmitter combined with the ever elusive Harris STX-1B AM stereo C-QuAM exciter. KYET is licensed by the FCC for 6kW days and one-watt nights into an omni-directional antenna pattern.

    KYET's Chief Engineer says that they experienced very little difficulty in making their Harris transmitter play with the Harris stereo exciter. Rather, it was much more challenging to get the stereophonic sound from the studio to their transmitter site. "Most AM stations only need either a single narrow-band STL channel, or a dry telco circuit, or even in some cases, a POTS [plain old telephone service] line. But because we are an AM stereo music station, we need the best sounding dual-channel STL possible." KYET's transmitter is approximately 2.5 miles from the studio, and it sits on the other side of a mountain pass. So not even the tip of the 190-foot tall tower, near the junction of US93 and SR68, is visible from the roof. "Because there was no [telephone] service to our area, and the nearest telco junction box is 7,500 feet away, the local phone company wanted $42,000 to run a single residential grade phone line, with no guarantee DSL would work on it. About the only thing we could do was to partner with Datamax Wireless, who brings us 20Mbps up and down to make the I.P-based STL run. And that is actually better than the DSL connection we have at the station," says KYET's Chief Engineer. "We are currently using a pair of Barix Exstreamer 500's running MP3 compression 16-bit Stereo 48kHz, at about 256kbps, and it sounds pretty good when it hits the air. ... We are using the built-in limiter, typically running at six to 10dB of compression, and there is no other audio enhancement gear in the air chain." Since the exciter sat unused for about 12 years, the power supply required some initial repair, and the exciter was also recently modified to provide the proper NRSC pre-emphasis curve, with 10 kHz low-pass filtering.

    KYET claims to be heard in Barstow, California, Wickenburg, California and loud and clear to north Las Vegas, Nevada. KYET will originate local news and talk, while maintaining the traditional country music format.



    WXYG "THE GOAT" now broadcasts magnificent C-QuAM AM STEREO to their many listeners in St. Cloud and all of central Minnesota, as of Friday, May 3, 2013. WXYG formats album oriented rock music, playing from a large library of deep classic rock album cuts. WXYG is locally owned and operated, not a satellite feed from somewhere. WXYG's goal is to make the music they play an (un)boring listening experience. There is so much great music from the golden age of the progressive rock era. Therefore, this is not a classic rock station where they play the same 200 songs over and over again. Now presenting a new age in broadcast radio - WXYG returns the power of great music to the people. WXYG was officially launched at 5:40 A.M. on June 25, 2011 -- which was owner Herb Hoppe's 77th birthday! WXYG has Nautel ND-1 transmitter with Gates BC-1G as back-up transmitter. WXYG power is 250 watts day/night using four towers on the daytime pattern, as well as three towers on the night pattern. You can listen world-wide at>> WXYG AM STEREO.



    2CA, as heard at 1053 kHz in Canberra, Australian Capital Territory, has discontinued their analog C-QuAM stereo broadcasts to their listeners. With the DAB+ digital stereo launch, 2CA began exclusively airing their "Forever Classic" music format in the digital stereo format. Immediately after 2CA discontinued analog 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 opportunity has vanished, as station management decided to permanently discontinue analog AM stereo broadcasts to their listeners! 2CA's Internet streaming service was also discontinued. This was due to a federal court ruling that streaming of this service over the Internet was not any longer considered to be a simultaneous transmission of 2CA's medium wave radio broadcast. As a consequence, there were music licensing issues that prevent 2CA from continuing to provide this web stream. 2CA is still available to listen to ON-AIR at 1053AM in MONAURAL.




    Australian hi-fi magazine is Australia's number-one premiere guide to home audio and home theatre technology. In the Australian hi-fi July-August 2011 magazine issue, beginning on page 82, Timoshenko Aslanides discusses analog AM stereo C-QuAM broadcasting to the more recent broadcasts from AM medium wave stations using the new DAB+ digital stereo technology in Australia. Timoshenko listened to 2CA from Canberra using his meduci AMX2000 tuner, and he directly compared those analog stereo signals to the simultaneous DAB+ digital audio stereo broadcasts. Can you guess which technology was victorious in the listening wars, and which won the battle of the radio bands? First, order this magazine copy from Zinio from this link>> Battle of the Bandsand then read this feature article here>> at this link.


    Kintronic Laboratories

    Bobby Cox and Tom King from Kintronic Laboratories showed their fondness for C-QuAM AM stereo by proclaiming "Come hear what AM Radio can really sound like using today's technology." They also answered questions in their booth at the National Association of Broadcasters Spring 2014 show, and discussed C-QuAM AM stereo technology and the FCC petition that they organized to improve the AM broadcast band. Anyone willing to listen to high fidelity AM audio was greeted with a pair of headphones for a shoot-out test. Both the Carver TX-11a and Sony XDR-F1HD tuners definitely showed the disparate differences in AM tuner audio bandwidth and distortion in these headphones. Alan Alsobrook and The Broadcasters' Desktop Resource reported on the NAB festivities.

    Tom King wrote letter to the Federal Communications Commission (FCC) on September 04, 2014 regarding the AM Revitalization process (FCC NPRM Docket No. 13-249):

    Subject: Meeting with FCC Commissioner Ajit Pai and Mr. Peter Doyle,
    Chief of the Audio Division of the FCC Media Bureau
    at the offices of the FCC in Washington, DC on Tuesday, September 23, 2014.

    To All AM Broadcasters in the USA:

    Kintronic Labs is concerned about the declining position of the AM radio service in the United States, which we reflected in our Reply Comments to the FCC NPRM Docket No. 13-249 on the subject of "AM Revitalization," issued on October 31, 2013. In the interest of preserving this great national resource for local public media, we have scheduled a meeting with FCC Commissioner Ajit Pai and Audio Media Chief, Mr. Peter Doyle, to address what we believe are the critical steps toward putting AM radio on a more competitive basis with FM as follows:

    (1) FCC enforcement of regulations relative to the power distribution industry and the consumer electronics industry that are not currently being enforced, resulting in a constantly worsening electromagnetic environment for AM radio service.

    (2) The need for parity between AM and FM receivers through the establishment of minimum technical standards for AM receivers that would become effective as soon as January 2016. We plan to demonstrate a comparison of full-bandwidth C-QuAM AM stereo reception with a local FM station and with a typical AM receiver in a popular consumer multi-band receiver. The effects of adjusting the AM bandwidth from 2.5 to 10 kHz in 2.5-kHz steps will also be demonstrated.

    (3) The need for FCC authorization of AM synchronous boosters. Unlike FM translators, such on-channel boosters would serve to increase the AM stations' audiences while concurrently maintaining the future viability of the band. The related technique of wide-area AM synchronization for coverage improvement will also be addressed.

    Referring to Step #2, it is absolutely essential that very close to full parity be established for new AM radio receivers versus their FM radio counterparts. This includes all key AM receiver performance attributes, including:

  • Low internal noise floor, well below the average AM-band atmospheric noise level. This includes all internal synthesizer and DSP circuitry within the receiver (and in the immediate environment for integrated automotive applications).
  • High overall RF sensitivity, selectivity, and dynamic range, to provide adequate amplification of weak signals, even in the presence of significant adjacent- and/or alternate-channel signals, especially in strong-signal environments. This would incorporate typical advanced, multi-stage AGC action, with appropriate interaction between the RF and IF AGC control mechanisms to maximize overall receiver dynamic range, including adaptive front-end attenuation for signal-overload protection in very strong-signal areas. Useful typical specs include: sensitivity - 1 mV for 10-dB SNR; selectivity (adjacent-channel) - 25-50 dB (adaptive).
  • Highly effective noise (EMI) rejection, including staged RF and IF noise blanking, accompanied by appropriate audio blanking and/or expansion when required. Such features were developed and included in Motorola chip sets in the 1990's in the AMAX program, and are easily integrated into modern, high-density AM/FM receiver chips.
  • Full 10-kHz audio bandwidth capability with low detector distortion. This would obviously incorporate dynamic, signal-controlled bandwidth control (including AMAX-style adaptive 10-kHz notch filtering) as dictated by noise and adjacent-channel interference.
  • Stereo capability. If the receiver has FM stereo capability, it must have corresponding C-QuAM decoding for AM.

    Without fulfillment of the first three requirements (this also includes the associated AM antennas both for vehicles and for home use), basic AM reception will suffer significantly compared with FM. Without the last two, the output sound quality cannot be closely competitive with FM (i.e., 10-kHz full bandwidth on AM versus 15-kHz nominal for FM).

    We therefore petition the FCC to mandate the following minimum allowable performance specifications for all AM receivers that will be manufactured and installed in new automobiles as of January 1, 2016:

    Audio Bandwidth: 10 kHz typical, adaptive, with a minimum nominal bandwidth of 7.5 kHz
    Signal-to-Noise Ratio: minimum 55 dB, preferably 60 dB
    Sensitivity: -120 dBm for a signal-to-noise ratio (SNR) of 10 dB
    Selectivity: 25-50 dB (adaptive filtering, using co-, adjacent-, and alternate-channel detection)
    Dynamic Range: 100 dB
    Noise Figure: 1 - 3 dB
    Image Rejection: -50 dB
    Intermod: IP2 , IP3 intercepts +10 to +40 dBm
    IF: low with image-rejecting down-conversion, or double-conversion
    Stereo Separation: minimum 25 dB

    Respectfully Submitted,
    Tom F. King


    Federal Communications Commission was seeking electronic comments in its filing system to revitalize the AM radio service broadcast band in the United States until January 21, 2014. This was our chance to be heard on this important issue! Further details are located here>> Proceeding Docket Media Bureau 13-249.

    Brian J. Henry of Napa, California, completely understands what needs to be changed for the AM broadcast band to be revitalized! Brian writes, "Without an improvement in AM broadcast receivers, there can be no AM revitalization! The single biggest factor in the technical decline of AM broadcasting lies with the deterioration in receiver performance. The vast majority of AM broadcast receivers do not have wide bandwidth audio frequency response that matches the transmitted audio frequency response, and their audio frequency distortion performance is orders magnitude worse than that of the worst commercial AM broadcast transmitter ever manufactured. I believe that the public interest would be served by The Commission mandating an analog audio quality standard for AM broadcast modulation and demodulation with flat end-to-end audio frequency response from 50Hz to at least 7.5kHz- with a 10kHz receive notch filter, and low audio frequency distortion that is modeled after the Electronic Industries Association and National Association of Broadcasters AMAX certification program to help AM regain some of its technical footing." We agree with Brian's comments and also support the AMAX initiative, authored more than 20 years ago, and still worth its weight today. In order for AM fidelity to improve, there has to be received analog audio fidelity complemented by the broadcast audio fidelity.

    Matt Krick, AM music station engineer, writes to the FCC: "It has come to my attention that the vast majority of AM receivers on the market are designed with 'Good Enough' mentality and quite frankly make anything received sound like mud. I'd like to propose the FCC implement requirements for manufacturers of radios to actually design a decent performing receiver."

    Say good bye to muddy sound. ...

    meduci has answered your calls! Wideband high fidelity AM analog tuners are available from meduci since late 2005. Unlike conventional AM radios, meduci tuners are optimized for music, and reproduce many limitations of the air interface and AM station's transmitter. This increased fidelity and crisp reproduction of the transmitted source program material may now be fully enjoyed and appreciated by the audiophile expert. For the first time in radio history, AM fidelity is not strictly limited by the receiving equipment.

    Virtually all other available AM medium wave receivers and tuners drop audio fidelity to 2kHz maximum response. This is good for a telephone conversation, however not for long-term listening sessions to high definition music programing.

    Will the FCC mandate that all manufacturers to build and to sell higher fidelity AM radios? This is not likely. FCC is not in the business to advocate how well an AM radio receiver sounds or receives stations in its overall performance. Can the FCC stop the HD Radio madness on the AM broadcast band? Yes, definitely!

    Brian J. Henry further writes, "The vast majority of licensed AM radio stations are not embracing in-band / on-channel digital operation and those that are only exacerbate an already bad situation with regard to interference to analog operation, particularly at night. There is unfortunately no way for there to be a high fidelity analog AM broadcast transmission system when there is a digital service operating in the audio pass band between 5kHz and 15kHz. The current combination approach is not benefiting either technology. They simply are not compatible. I feel that the public interest would be better served if the Commission authorized full AM digital operation at the broadcaster's discretion in lieu of analog operation. Implementing AM stereo may be a viable path forward for AM broadcasters until enough digital receivers have been acquired by the public to make the switch to all-digital transmission a worthwhile consideration, especially since some recently manufactured HD receivers are able to decode C-QuAM AM stereo."

    WBT "NewsTalk 1110" in Charlotte, North Carolina conducted an all-digital HD Radio test broadcast on August 18, 2013 to meaure the strength and fidelity of their broadcast. We heard this all-digital HD Radio test broadcast, and we were not impressed with the WBT HD audio sound quality. It was far from being exceptional. In fact, it sounded very artificial, especially when music snippets were played. This all-digital transmission method will not revitalize the AM broadcast band. WBT also reportedly used an omni-directional pattern during the all-digital test, since their directional pattern was not up to the task. WBT has not conducted subsequent tests, and we can only conclude that the all-digital test failed.

    During their promotional announcement, it was stated, "WBT is one of a handful of radio stations in America that is capable of broadcasting in digital HD." We agree with that statement. There are many technical reasons why HD Radio is not more widespread, especially for night-time AM broadcasts.

    What can you do to receive better sounding analog AM radio broadcasts? meduci sells quality wideband high fidelity AM stereo tuners and decoders intended for the C-QuAM stereo format. Our newest model, the MW-2 PLL tuner, boasts recovered audio bandwidth beyond 10kHz in the "wide" mode, and 5kHz bandwidth in the "narrow" mode. This fidelity competes with other media devices. Our tuner is the answer to the availability shortage for high fidelity AM tuners today. Our analog tuners are intended to be a large part of the AM broadcast band revitalization process.

    Model: MW2 PLL Tuner Front


    Introducing our new MW-2 PLL high fidelity wide band electronic tuner, which showcases high fidelity wide band fidelity sound with very low audio distortion! This professional quality MW-2 PLL tuner is our most advanced tuner offered to date -- updated and re-packaged to build upon the renowned strengths of our two previous consumer AM stereo tuner models. Instead of littering the front panel with seldom-used buttons and features (such as with some tuners from other sources), this meduci MW-2 PLL tuner concentrates on the essentials, with additional new standard features that increase its curbside appeal:

  • WIDE / NARROW BANDWIDTH SELECTION -- This standard feature allows you to narrow the tuner's I.F bandwidth for night-time conditions or for DXing weaker stations. Being stuck with one extra-narrow or extra-wide audio bandwidth is not all that practical for the different reception conditions that we encounter on the AM band from day-to-night -- this dual bandwidth feature provides the MW-2 PLL tuner with much more versatile operation.
  • NRSC AUDIO DE-EMPHASIS SELECTION -- This is another appreciated feature that improves the audio frequency response from those AM stations that transmit with the NRSC audio pre-emphasis curve.
  • AUTO STEREO / FORCED MONO SELECTION -- There may be rare instances when a received mono AM station may false trigger the C-QuAM stereo decoder circuitry into action. In this case, you would want the forced mono selection to be enabled.
  • BRIGHT RED LARGE AM STEREO INDICATOR -- Provides solid confirmation that you are listening to C-QuAM stereo broadcasts (where available). This AM stereo indicator is not present on any other new receiver offered today, however you can find it on the front panel of your new MW-2 PLL tuner!
  • ROTARY CONTINUOUS DIGITAL TUNING KNOB -- An intuitively simple device for manually tuning to your desired station's frequency. This rotary continuous tuning mechanism does not have any mechanical analog tuning stops, so you can tune directly, instantly, and simply from the band edges (say from 530kHz to 1710kHz) or in-between these band edges on the station dial.
  • CENTER TUNING LOCK INDICATION -- This feature provides positive confirmation that you are centered and locked onto your favorite AM station's signal! This green indicator is integrated into the rather large, bright, high contrast 24-segment green digital numeric frequency display (14.2mm, 0.56" height) in the upper right area.
  • Boasting better-than-broadcast quality reception, and extremely low noise across the audio spectrum, your MW-2 PLL tuner is a winner in both function and performance.

    This new MW-2 PLL tuner has rock solid and stable operation -- with user interface directly under microprocessor control -- and this tuner even makes mono AM stations sound better!

    Received stations are drift-free thanks to Motorola Quartz Crystal Synthesized Phase Locked Loop (PLL) Continuous Electronic Tuning. This evolutionary feature eliminates all microphonics, unstable operation, and tuning drift. Also, the tuning range is not condensed in the upper end of the broadcast band. Touching the tuning knob or moving the tuner will not upset the lock on AM stereo stations.

    Either 9kHz or 10kHz station tuning steps are included in this new phase stable design, based upon tuner's shipping destination at the time of order placement.

    Highly Effective Automatic Noise Limiter -- Reduces impulse noise pops from the audio output.

    We made several cosmetic improvements to the overall external appearance! These improvements include black exterior, with nice contrasting white lettering on front and rear aluminum panels. All is housed in new attractive black ABS plastic cabinet, which measures 179.5mm long by 154mm wide by 51mm height. Excellent sound, ease of use, and convenient features are all wrapped up in this MW-2 PLL wallet-friendly tuner, ready for the devoted audiophile's tuner collection! Your MW-2 PLL tuner is designed for high fidelity reception from local and regional AM stations. Unfortunately, the wider bandwidth from MW-2 PLL tuner does not afford satisfactory listening from very distant AM stations.

    We strive to earn customers for life. This tuner is new, hand-made to order, and is directly sold from the manufacturer. Assembled in the United States of America from U.S and globally-sourced parts.

    Each MW-2 PLL has the features and performance to make it THE LEADER among all AM Stereo tuners available today.
    For MW-2 PLL Owner's Manual, please click on>> this link.


    John Holcomb (the second) from The Villages, Florida USA shared air checks from WVLG(AM) Wildwood, Florida in February 2014. This demonstrates that mono AM stations sound very good when properly received on a high fidelity wideband AM radio!

    John says, "Thought I'd send you a copy of this file here. Recorded from my AMX2000. As you know WVLG doesn't stream, and man [their] AM sounds excellent! Feel free to share on your website if you'd like to showcase an example of good quality AM. I can also get WLBE (which has less compression and more of a dynamic range). It is sure an unique listen in that you never know what will come up next." John is using his>>TERK Technologies Audiovox AM Advantage 1000 passive antenna. There is a 12-foot long cable connected between this Terk antenna and his AMX2000 tuner. This cable allows the antenna to be located far away from his mixer and computer- to obtain good naturally-sounding reception with very low audio distortion. John is are fortunate not to have any local man-made electrical interference in his central Florida reception area.

    WVLG programs soft adult contemporary music format, playing songs from the 1950's to the 1980's. Ron Richards was spinning the records during this air shift:


    Rob Nuton was spinning the records during these additional WVLG air checks recorded on February 4, 2014 from meduci AMX2000 tuner in WAV high quality uncompressed loss-less quality audio format:



    This has the Love Shack original length song track from the B-52's that was never played on radio stations back in the 1980's: WVLG(AM) PART FOUR IN WAV AUDIO FORMAT (56.3MB)

    WLBE(AM) Leesburg-Eustis, Florida USA is another regular station favorite that is listened to by John Holcomb II--this time to the local Uncle Rusty program on February 4, 2014. It is a rarity for two locally programed AM music stations to co-exist in the same radio market these days! Again, this is in WAV high quality uncompressed loss-less quality audio formatting:




    John says, "A bit about WLBE. Last year, they hired a new PD to transform this station from a talk format to a hybrid of oldies/talk. They don't always have live DJ's, but I made it a point to record when there was one. They differentiate themselves from WVLG by leaning [to] older oldies. WLBE does stream, and the stream is in stereo. I remember last year on the radio discussions board there being talk of putting the station on in AM stereo, but if my memory serves me right, [they were] not being sure how to get the studio to transmitter link in stereo."

    According to John, "Both WVLG and WLBE would sound excellent in AM stereo! I personally think that WLBE gives more accurate sound of what your tuner can do for an AM mono station. ... Your tuner proves in these [audio] samples that yes, AM can sound good, and engineers do care about what goes on between the speakers. After all, this is an audio medium. Formats on AM not only need to have good content, but the manufacturers of the receivers need to do their part too."

    John says, "A little more about my setup. I have your tuner running into a Numark mixer, which is connected to a Behringer U Control UCA222- which runs into my Dell Inspiron E-1705 laptop running Windows XP. I've recorded this in Sony Sound Forge 8.0 in *.wav format, before editing and saving it." This is an incredible listening experience from two mono music AM stations. Thank you for taking the time and making the effort to share, John! WVLG and WLBE chief engineers and owners should also be recognized for their achievements. Just imagine the extra dimension and wide musical separation if these two stations were broadcast in C-QuAM stereo!


    Takuya Kadowaki shared two air checks, as recorded from his AMX2000 tuner in Japan in July 2008. Please listen and let us know your thoughts:




    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. Your ears are in for a very nice treat! You can download the entire show at once, or get it in one-hour time blocks>> Robb_Radio_Show_110510

    This direct off-air recording from Stereo 1630 KCJJ demonstrates how well analog AM stereo rules, and shows the full 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.




    On April 14th 2011, Tab Patterson again visited the Robb Spewak Show on KCJJ in Coralville, Iowa USA and made radio history with his successful Quadraphonic Radio test over C-QuAM stereo technology! This clip >>from USTREAM contains the direct live audio feed from the studio, as well as video taken from a stationary camera. Quadraphonic test begins at approximately 30 minutes into this video stream. Remember that left and right channels are reversed on the USTREAM feed. You can also watch Tab Patterson's video that takes the over-the-air sound recording from KCJJ using his PRO1k tuner. This video 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 was a 12-minute long experimental broadcast to see if Quadraphonic Sound could indeed 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 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_MP3

    Tab 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 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!

    Sadly, KCJJ elected to discontinue their AM stereo broadcasting in November 2012. From KCJJ: "We could not justify sacrificing almost 15 percent of our modulation to a technology that isn't available anymore. It's sad, because it did work nicely, but our local coverage did improve, and we could no longer get service on the exciter. Thanks for listening. KCJJ Staff." Ironically, Robb Spewak said to Steve Bridges at the end of his 12-minute legendary quadraphonic broadcast:

    "Remember Steve, it's twice as good in stereo."

    Two mono AM stations have recently contacted us and will be converting their transmission plants to AM stereo in USA. We will announce new AM stereo launches at these two AM stations when they are ready. It seems that for each AM stereo station that falls, another one rises in its place. Stay tuned to meduci's web site for further updates! And please remember to promote AM Stereo at least ten times per day on your station -- in hourly station identification: call letters, followed by community of license, followed by the magical two words "AM STEREO" !! And regularly promote AM Stereo on your web sites, with the two words "AM STEREO" listed in your station logo! This promotion will make a big difference with your listeners.


    Courtesy of Josh Jones, complete service manuals are available for MOTOROLA MODEL 1300 C-QuAM AM STEREO EXCITER, MOTOROLA MODEL 1310 C-QuAM MODULATION MONITOR, DELTA ELECTRONICS ASE-2 C-QuAM AM STEREO EXCITER, as well as DELTA ELECTRONICS ASM-1 C-QuAM MODULATION MONITOR. Schematic diagrams and complete parts lists are also included for all manuals. You can download the combined Motorola 249-page service manual here>> MOTOROLA SERVICE MANUAL (34MB) . You can download the Delta Electronics service manuals here>> DELTA ASE-2 SERVICE MANUALS (12.1MB) and DELTA ASM-1 SERVICE MANUALS (15.25MB).

    Bill Norman


    Bill Norman, owner of WNMB-AM, Norman Communications NMB Incorporated, and co-owner for WVCO-FM "The Surf 94.9" passed away on October 14th, 2012. WNMB(AM) is licensed to North Myrtle Beach, South Carolina USA. WVCO-FM is licensed to Loris, South Carolina USA. Bill was a strong advocate for live radio origination, and not a proponent for the style from the voice-tracking cookie-cutter automated formats from corporate radio. He was very active in his local community, and also provided the local voice through his stereo radio stations. Bill enjoyed broadcasting AM stereo, and showcased his talent in the office reception areas for his radio stations. There were many AM stereo radios displayed for listeners to sample WNMB. There are not many people in the world that showed so much devotion, and cared about their local community, like Bill Norman. Read the story here>> from Myrtle Beach Online.

    Soon after the meduci AMX2000 tuner was launched, Bill exchanged several e-mail with us, and he requested us to send one AMX2000 tuner to him. Bill also sent video commercials, air checks, logo, and artwork for his WNMB ("Wonderful North Myrtle Beach") AM stereo station, so that we could use for promotion on our web sites. Bill wrote to us, "We believe in AM Radio and in the great stereo sound. ... Just busy all the time and trying to juggle lots of things between day-to-day sales, radio programing, and community things."

    On Monday, December 19th, 2005 at 3:30 p.m. Eastern time, Bill activated his new Delta AM stereo exciter at WNMB. Pilot lights on the AM stereo tuners came on in the studio, and the channel separation was immediately evident as "All I Want For Christmas" became the first song played in AM stereo on WNMB. Audio chain consisted of stereo BE console to a stereo generator, which was fed into a new Armstrong composite STL. This STL was received on the companion Armstrong receiver at WNMB's transmitter site, which is approximately five miles inland from the studios. From the STL to an Orban Optimod 9100A AM stereo processor, and the Delta AM stereo exciter, then to the Gates One AM transmitter. Bill also used one companion Delta AM stereo modulation monitor. Rest in peace, Bill, our friend (May 8, 1949 to October 14, 2012).


    It is with deep regret that we pass along the following news: Broadcast veteran Herb Squire confirmed that Leonard R. Kahn, the CEO head of Kahn Communications, passed away from natural causes on June 3, 2012 in south Florida USA at the age of 86 years old.

    It has been said that pioneers have arrows stuck to their backs. Kahn was a true pioneer in the AM stereo wars, and took many arrows in his back over the years. Kahn was best known for his ISB AM stereo analog transmission / reception system that actually dated back to 1959, when Kahn worked for RCA Laboratories. This ISB system was not afraid of the dark. Kahn also created the "Symmetra-peak" technology in the late 1950's, that directly competed with Volumax and Audimax from CBS. Kahn's Symmetra-peak was a passive device, that equalized the positive and negative audio peaks that were sent to an AM broadcast station's transmitter. Symmetra-peak system increased the modulation density by several dB prior to the existence for sophisticated multi-band audio processing systems, per Squire. Kahn's other more recent inventions included PowerSide and CAM-D. PowerSide injected independent aural modulated information into one of the two AM broadcast sidebands. PowerSide improves reception from AM stations primarily on manually-tuned AM receivers, especially when first and second adjacent stations are present. CAM-D is an in-band, on-channel digital technology for AM stereo reception, intended to directly compete with iBiquity's HD Radio digital radio system for the domestic AM broadcast band.

    Kahn did make contact with us in 2005 from his New York office. He loved AM radio very much!

    It is not clear at this time who will continue to service, uphold, support, and to upgrade the Kahn CAM-D and PowerSide technologies and equipment currently being used at AM stations. Kahn held several hundred U.S patents >> read the Kahn Patents here. Kahn was also an Amateur Radio operator (license: WB2SSP). Kahn lost his wife, Ruth, in 2005. Kahn does not have any known survivors. May he rest in peace.


    Joe Dentici

    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-B 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 written e-mail 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.

    Simply the Best!

    It is with great sadness that we reported the passing of Edwin R. 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!

    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).

    Prior to arriving at WJR(AM), Ed engineered the signature sound for 13 years at CKLW(AM) "The Big 8" (Windsor, Ontario Canada) in its heyday as a 50kW Top-40 popular music station powerhouse. AM_ST
    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. Ed believed in providing the best experience to listeners during his tenure at the station. 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.


    We wish to thank LORNE TYNDALE, who is Engineering/IT Support at CKLW, CKWW, CIDR, and CIMX- for furnishing this comprehensive Harris V-CPM test report, as written by Ed Buterbaugh and published on July 13, 1979. We are certain that this report will spark some discussion, including the findings and conclusion that the Harris V-CPM system did not degrade, diminish, or decrease the coverage area or signal-to-noise ratio on existing monophonic receivers. It was reported that adding AM stereo does not in any way reduce the mono coverage area; it simply adds a new stereo coverage area over most of the existing mono coverage area. Also, as far as Lorne is aware, the report itself is a part of FCC and CRTC/Industry Canada public domain information, and at this point, the information the report contains is historical, since the Motorola C-QuAM standard was chosen, as opposed to the Harris V-CPM system.

    It is interesting to note - the original test proposal called for conducting the same tests using each of the five competing systems from Harris, Magnavox, Motorola, Belar, and Kahn. The proposal was to conduct one week of testing on each system (running the same tests on each). Lorne says that he is only able to find test results/reports for the Harris V-CPM system. Lorne suspects that testing was only performed on the Harris system, but further research would be needed to confirm this suspicion. Lorne knows that when CKLW received permission to broadcast AM Stereo full time (not just for testing), it was the Harris sytem that was selected to be ON AIR at CKLW.

    History of AM Stereo

    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 the late 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. Several 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.

    About us

    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.

    Please inquire for further details, and do not forget to mention "AM stereo" (without quotes) in the subject line. Write to amstereo'AT' (replace 'AT' with the @ sign).
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    This web page was updated on Sunday, November 2, 2014.

    Information listed herein is subject to change without notice. All rights and trademarks are the properties of their respective owners.
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