[Milsurplus] More Fun with BC-230 - 30 Meters

[Brian Carling]

I love beam power tubes. I never have any difficulty with self oscillation problems. On the other hand TRIODES in common cathode circuits can sometimes be almost untamable.

Prime example: 
Pair of V70D tubes in the RF final of the Globe King 400 transmitter. 

Best regards - Bry Carling



> On Aug 3, 2014, at 10:53 AM, Richard <brunneraa1p at comcast.net> wrote:
> 
> About the 5763:  See "Intrinsic Negative Resistance as a Cause of Parasitic Oscillations in Beam Power Tubes," by David Newkirk," for more than you want to know.  The 5763 is an exemplary example, and "may" be cured by adding a 100 Ohm non-inductive resistor between the screen terminal and bypass capacitor.  I personally practice Beam Power Tube Avoidance.
> 
> Richard, AA1P
> 
>> On 08/03/2014 07:48 AM, David Stinson wrote:
>> While working on a way to get the BC-230 5-6 MC coil to
>> scoot-up to 40 meters, I managed to booger-ize one of
>> the PA Tank/Antenna coils.
>> Rather than can it, I rewound it.  Used the BC-230 with
>> the 6AQ5s  (have abandoned the 5763s- too hard to
>> neutralize and de-FM).  Unwound the tinned coil wire,
>> covered the thin, fragile link coil under it with a single layer
>> of tape and used the tinned wire to wind a 12-turn tank coil.
>> Yes; the wire's "lumpy" from being on that form.
>> I'll rewind it with fresh wire later.
>> Here's a crummy picture:
>> http://home.netcom.com/~arc5/SCR-183/230-30m.jpg
> 
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