[Milsurplus] MAB vs BC-611

[WA5CAB at cs.com]

Mike,

You mean "B-Battery" of course.  But I've tuned up dozens of BC-611's over 
the years, using an I-135 and a PP-351/U set to about 100 Volts.  Plate current 
at the dip typically runs 6-10 MA.  Which any way you cut it is half a watt or 
more input.

In a message dated 7/12/2005 3:31:28 PM Central Daylight Time, 
kk5f at earthlink.net writes: 
> The manuals I've seen say ".035 watts" output, but I contend that it should 
> be "0.35 watts" output.  The PA tube plate, when using an A-battery with 
> reduced voltage of 90 vdc, should according to the manual have about 70 vdc on 
> the plate and draw 7 mA when the tank coil is properly dipped for minimum 
> current.  That would be about 0.49 watts input.  If a fresh A-battery (103.5 vdc) 
> were used, the plate voltage would likely be about 83 vdc, so 7 mA plate 
> current would cause 0.58 watts input.  The PA appears to be a fairly 
> garden-variety class-C amp, which should have perhaps 70 percent or better efficiency.  
> So a reasonable power output expectation would range from about 0.34 to 0.41 
> watts.  A power output of only 0.035 watts would mean that the PA efficiency 
> was only about 7 percent!

Robert Downs - Houston
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MVPA 9480
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