[Amps] 813 efficiency

Carl km1h at jeremy.mv.com
Tue Feb 26 14:09:10 EST 2013


Mount 4 up and 4 hanging down. Feed the cathodes thru a 2 port splitter and 
200W+ drive.

10-4 and Yee Haw

Carl
KM1H


----- Original Message ----- 
From: "Robert Groh" <rgroh at swbell.net>
To: "k7fm" <k7fm at teleport.com>; "Amps" <amps at contesting.com>
Sent: Monday, February 25, 2013 1:12 PM
Subject: Re: [Amps] 813 efficiency


> Love your comments, Colin. I visualize a 'ring' of 813's (like the 
> cylinders of
> an old radial airplane engine) - bases all toward the center. All behind a 
> big
> window (you just have to be able to see the plates glowing red as you 
> throw the
> RF to them).  No, maybe a better idea to flip the tubes end-for-end 
> (better to
> combine the RF outputs).  Cooling - maybe a big fan (box fan??) directly 
> behind
> the tubes and pull the hot air out radially.  Actually maybe set up for 13 
> tubes
> but the 13th tube position doesn't have a tube there - this is just a 
> place to
> have the tuning controls coming out.  Crazy?  Maybe.  Great idea for the 
> April
> 2014 issue of QST.  Wow.  I've got to work on that.
>
> 73
> Bob, WA2CKY
>
>
>
>
> ________________________________
> From: k7fm <k7fm at teleport.com>
> To: Bill Turner <dezrat1242 at yahoo.com>; Amps <amps at contesting.com>
> Sent: Mon, February 25, 2013 8:58:54 AM
> Subject: Re: [Amps] 813 efficiency
>
> REPLY:
> To get the plate dissipation of a single 8877 would take 12 813s.
>
> Would you put them all in a row?  Or a matrix of 3x4? Or 6x2?
> Or maybe in a circle?  Can't wait to hear.  :-)
>
> Good question.  With 12, you could place them like a clock face, then be 
> able to
> identify the bad tube by the time - except that the modern folks may not 
> be able
> to read a clock face.  To a digital guy, 12 o'clock high means having a 
> joint
> with lunch.
>
> 73,  Colin  K7FM
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