[AMPS] 3CX3000F7 design criteria

[Rich Measures]

>
>Hi,
>
>A colleague of mine has accumulated a large collection of amplifier parts,
>and is ready to embark on building an HF amp using an Eimac 3CX3000F7
>(that's the one with "tails").
>
>Are there any problems or pitfalls with designing an amplifier, using this
>specific tube, to run on 1.8-21MHz? Obviously, it needs lotsa drive.
>Anything else?
>
Float the fil. transformer on g10 fiberglas board, bypass all windings to 
the core, and use a 3a bifilar fil. choke wound of c.10uH made with #20 
ga. wire in the 240v primary of the transformer.  //  Some builders have 
experienced osc. in the 70 MHz range, so you may want to use low vhf Q 
parasitic suppressors.  //  If the tube has not been purchased:  An 8171 
drives with 150w, has up to 20db gain, is Much easier to cool, has a much 
simpler tuned input, requires no fil. choke, and it has much more 
emission.  
>
-  later, Al


Rich...

R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures  


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