Re: [Amps] SB-220 6M conversion

[Jim <jimw7ry@gmail.com>]

Good article except for tearing out the original relay. Not necessary, 
unless you want to use QSK or hate the sound of loud relays (like I do).

Thanks
73
Jim W7RY

On 6/5/2020 10:24 PM, Adrian wrote:
> Have you seen this one Steve ?  ;
>
> http://www.arrl.org/files/file/Technology/QST_Apr_2008_p38-40.pdf
>
>
> On 6/6/20 1:10 pm, Artek Manuals wrote:
> > I have enough HF amps here (four at last count) One of them is an 
> > ancient SB-220 , so I thought what the heck I would "hack" it and 
> > turn it into a 6M single band. I have a folder  full of articles on 
> > how to from the last 20 + years.
> > All done "physically" but try as I may I can not get more than about 
> > 600w out .
> > 1) Two different tank circuits , one with a section of the original 
> > 10/15  coil from the SB220 and a 2nd one with a a piece of flat 
> > copper strap ...no difference
> > 2) Changed the parasitic chokes
> > 3) Tried  "T" input match. Pi input match , straight through ...no 
> > difference
> > 4) Plate voltage is 2400 unloaded and about 2050 loaded in CW position
> > 5) Bias measures 6V
> > 7) Has new Hardbach bias and diode and metering board
> > 8) Older set of Eimac 3-500Z and newer set RF Parts 3-300ZG ...no 
> > difference
> >
> > What am I missing, ?
> > What else to try?
> >
> > Dave
> > NR1DX
> > manuals@artekmanuals.com
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