Solid-State Linear Power Amplifier Design by Hejhall -- Motorola AN-546, 1971

Discussion in 'Amateur Radio Amplifiers' started by W1UO, Nov 8, 2018.

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  1. W1UO

    W1UO Ham Member QRZ Page

    Anyone have a copy of this app note? I had a look on line but couldn't find it.
    Thanks. 73 Pete W1UO/6
  2. AC0OB

    AC0OB Subscriber QRZ Page

  3. W1UO

    W1UO Ham Member QRZ Page

    Thanks Phil,
    Not the one I was looking for but it looks like a good reference nonetheless. I'll file it away for future reference.
  4. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    I looked and couldn't find it, either.

    Tons of "references" to it, but couldn't find the actual AN; even the Motorola archives list it, discuss it, reference it, and don't seem to contain it.
  5. AA7QQ

    AA7QQ Ham Member QRZ Page

    Might be in an old Motorola book. I sure wish I had one from every 5 years.
    Maybe someone has it on the shelf.

    Is any specific transistor used in it? That may help.

  6. K6BSU

    K6BSU Ham Member QRZ Page

    You might consider the 300W linear amp by H. Granberg of Motorola. Uses MRF428A in push-pull. Originally published in QST Apr/May 1976 and reprinted in "Solid State Design For The Radio Amateur" by ARRL (but no longer in publication). I built one, and it works perfectly. I get only 100W because my power supply is just 18V. If interested, I can copy this for you. Send me an e-mail.

    K6BSU hi pwr linear amp.jpg
  7. W1UO

    W1UO Ham Member QRZ Page

  8. W9GB

    W9GB Ham Member QRZ Page

    Yes, later Motorola Application Notes (1970s, 1980s) often reference the 1971 Motorola AN-546, regarding transformer construction and core material usage.
    Chris Trask, N7ZWY principal engineer at Sonoran Radio Research (Tempe, AZ) covered the topic with references to modern Fair-Rite offerings (2005) in the March/April 2005 issue of QEX magazine.

    Designing Wide-band Transformers for HF and VHF Power Amplifiers
    by Chris Trask, N7ZWY
    Article discusses the alternatives available in the design of transformers for solid state RF amplifiers. The key parameters of different construction techniques are discussed with results shown for each.
    Opening article, for that issue, on Pages 3-15

    Fair-Rite Products Corporation generously supplied Chris with some of the specific ferrite cores that were evaluated and used in the preparation of the QEX article.
    Additional References:

    Ferrites and Accessories : Application Notes (May 2017)
    EPCOS AG, a TDK Group company

    NXP / Freescale / Motorola AN749
    Prepared by: H. Granberg, RF Circuits Engineering (1993)

    DL413 : Motorola’s 1994 Compilation of Application Notes (474 pages)
    Radio, RF, and Video Applications

    Soft Ferrites : A User’s Guide (SFG-98)
    Magnetic Materials Producers Association (Chicago, IL)
    Copyrights 1989, 1990, 1992, 1996, 1998 SFG-98.pdf

    MMPA Soft Ferrite Division
    Member Companies:

    AVX (formerly Thompson-CSF Passive Components)
    Ceramic Magentics, Inc.
    CMI Technology, Inc.
    Fair-Rite Products Corp.
    Ferronics Incorporated
    Hitachi Metals America, Ltd.
    Magnetics/Div. of Spang & Co.
    MMG-North America
    National Magnetics Group, Inc.
    Philips Advanced Ceramics
    Powdertech Corporation
    Siemens Passive Electronics Devices, Inc.
    Steward, Inc.
    TDK Corporation of America (EPCOS AG)
    TSC Ferrite International Co.
    Last edited: Nov 13, 2018
    EW3KO likes this.
  9. W1UO

    W1UO Ham Member QRZ Page

    Thanks Greg.
    I had forgotten about the QEX article.
    73 Pete
  10. WA1GFZ

    WA1GFZ Ham Member QRZ Page

    An758 T1 = type 73, T2 = type 61 and T3 =type 61. T2 core is a bit under sized . You can make 25 ohm coax from mil teflon single shielded wire I use #20 to handle the current but #22 is closer to 25 ohms. CCI get big bucks for the same stuff. Phillips apps are very good. Check Sept/Oct 2015 QEX. Shoot me your email address and I can send you some apps. Frank wa1gfz

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