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  • MW Radio 1st stage

    From G8MNY@21:5/101 to TECHNI on Sat Jul 27 03:20:25 2019
    R:190727/0611Z 21366@OK2PEN.SP.BRA.SOAM [Sao Jose dos Campos] $:13578_GB7CIP R:190727/0610Z @:N1URO.#CCT.CT.USA.NOAM #:26721 [Unionville] $:13578_GB7CIP R:190727/0610Z @:GB7CIP.#32.GBR.EURO #:13578 [Caterham Surrey GBR]

    From: G8MNY@GB7CIP.#32.GBR.EURO
    To : TECH@WW

    Here are 2 designs:-
    By G8MNY (New Graphics Dec 03)
    (8 Bit ASCII graphics use code page 437 or 850, Terminal Font)

    Example of multiple use of a single transistor in a MW radio that does:-
    1/ RF PREAMP WITH Q MULTIPLIER
    2/ RF LOCAL OSC
    3/ RF MIXER

    Power ───┬───┬───┐
    === │ )|| ______
    Decoupling│ === )||( 455kHz
    ─┴─ │ )||( IF output to next IF stage
    │ )||(______
    ├───┘ IF T1
    │ TRANSFORMER
    └─────────────┐ ||
    )||
    F || )|| OSC COIL
    E || Feedback )||
    R || ┌──────────────────────┘ ||
    I ||( RF Q Multiplying ||
    T ||( feedback coil ||
    E || └──────────┬─────┐ ||
    || bias │ ||
    R || R │/ ||
    O || ┌───┬──┤├──┴───┤ ||
    D ||( │ │\e ||
    ||( │ Tune └─┬───┐ ||
    A ||( === RF Tune │ )||
    E ||( L1 │ C1 OSC === )|| OSC COIL
    R ||( │ C2 │ )|| L2
    I || └───┴──────────────┴───┘ ||
    A || 0.53─1.6 MHz 0.9─2.1 MHz
    L ||

    ADJUSTMENTS
    The position of winding L1 on the ferrite adjusts the LF resonance tracking. The trimmer on C1 tuning cap adjusts the HF resonance tracking.
    The position of feedback winding, adjusts RF Q & gain before instability.
    The position of L1 core adjusts the LF dial frequency tracking.
    The trimmer on C2 tuning cap adjusts the HF dial frequency tracking.
    The position of T1 core adjusts the IF filter frequency, for best IF gain.

    ----------------------------------------------------------------------------

    From: ON4CBL@ON0AR.#RF.AN.BEL.EU
    Hello OM, here is a plan with 1 Tr rf det. + lf,, 2 Tr following for LS!
    : MW Radio 1st stage reaktieve:

    1/ RF PREAMP WITH Q MULTIPLIER + 1x LF LF<----|---> -9volt
    Stages /
    / 270
    ! /------| 4.7k | (anti-motorB)
    T1 ! \ _|_ 500pF |-------------|-----/////--------|
    ! / ___ Cv / 10 | |
    ! \------| / mH --- - ---- -
    ! OA81-85 / / --- + 10µF ---- + 100µF
    ! |-----|----|------| | |
    F ! | 0.1µ \ / | | ------
    E ! --- / | | ---- +
    R ! --- 680k / | | --
    I !A | | | / c |
    T ! --------------|---| AF116 |----|-----|
    E ! \ | Over! | \ e | |
    ! / | | | 1nF / 47k log
    R ! \ | T2 | --- P /----------
    O ! / | | --- / LF out
    D ! \ | 0.047µ | | |
    ! ---|----------||-----|--------|----------|----------
    ! 0.53-1.6 MHz -----
    B --- +
    -
    A/B changing for adjusting receiving.
    T1 40 wdgs cul 0.2
    T2 12 wdgs cul 0.2

    73 De Eric, ON4CBL @ ON0AR


    Why don't U send an interesting bul?

    73 De John, G8MNY @ GB7CIP

    --- Mystic BBS v1.12 A43 (Linux/32)
    * Origin: HAMRADIO telnet lu9dce.dynu.com (21:5/101)