[ARC5] Fw: Varying oscillator frequency. re: Anode voltage on tank coils ...

[Henry Mei'l's]

Thank you Robert.

BW
Henry 

PS: Just 1H: 10H would bloat my ego and get me all too wound up. But I'm still good at the core!)
        --Everyone send me very large chocolate bars and I might hold back on the quips--
  ----- Original Message ----- 
  From: WA5CAB at cs.com 
  To: meils at get2net.dk ; arc5 at mailman.qth.net 
  Sent: Sunday, April 17, 2011 4:50 PM
  Subject: Re: [ARC5] Fw: Varying oscillator frequency. re: Anode voltage on tank coils ...


  Henry,

  Yes, both the oscillator and the PA tank coils in all three Command Set transmitter variants have powdered iron cores for tracking adjustments.  And yes, the permeability of iron cores varys with flux density.  How much in this case I couldn't say.  But the DC flowing in the oscillator coil is the 1626 filament current (mainly) which shouldn't vary much.  

  I've always assumed that the reason for the shift from series to shunt feed in the ARC-5 PA was to reduce the peak voltage on the tuning and padder capacitors.  Maybe to raise the safe operating altitude or something like that.

  In a message dated 4/17/2011 7:26:17 AM Central Daylight Time, meils at get2net.dk writes: 

    I wasn't referring to inductors having metal (metallic) cores
    BUT don't the Command set transmitter oscillators use a
    powdered ferrite adjustment core? Shouldn't a DC current
    influence the core mU and thus coil inductance? Though assumedly
    not even approach saturation under normal transmitter operating conditions.
    (As far as I can see, Magnetrons/Klystrons operate on entirely
    different principles so I suppose my comparison was irrelevant.)

    Henry



    ----- Original Message ----- 
    From: "Henry Mei'l's" <meils at get2net.dk>
    To: <arc5 at mailman.qth.net>
    Sent: Sunday, April 17, 2011 12:08 PM
    Subject: Varying oscillator frequency. re: Anode voltage on tank coils in 
    the GF-11 and SCR-274N series Command transmitters


    >Pretty sure I've read that DC coil current flow is actually used to vary 
    >oscillator frequency.
    >I don't know if this is remotely relevant to klystron and/or magnetron 
    >burst pulse operation.
    >Back to the theory books for me or maybe some internet research unless 
    >someone like
    >Dennis, John, Ken, Les, and many more here .... can fill me.
    >(BTW if any are tired of my "witty comments" - what about me: I have to 
    >hear them
    >everywhere I go!  Maybe Mark Twain somehow sneaked into my family tree.)
    >
    >Henry
    >oz3o (oz1uf)  n2nr



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