[AMRadio] Subj change - HB designs


Brett gazdzinski brett.gazdzinski at verizonbusiness.com
Tue Jul 24 20:45:58 EDT 2007


>From a size standpoint, the 4-65 is not a great choice.
Running 2000 volts on the plates, you need a plate tuning cap
with about 5000 volt spacing to prevent arc overs on peaks.

Running 1000 volts you need say 2500 volts.

The RF output parts in say a DX100 are quite small.
Just the 5000 volt plate tuning cap (say 120pf) will
be the same size as the entire RF output section of the DX100.

Brett
N2DTS





> 
> Jim Wilhite wrote:
> > You are right Tony.  Why do 3 or 4 of them requiring a lot 
> of filament 
> > current when one could use one 4-250 or 4-400 or even two 4-125s.
> >
> > One 4-65 will only give 100 watts out in ideal circumstances if run 
> > full bore.  Might as well have a DX 100.
> 
> That's kind of the plan, Jim.  I want to build a table-top 
> transmitter, 
> using a single 4-65, modulated by a pair, in AB1.
> 
> I have a modulation transformer with a screen winding on it.  I could 
> use a common supply, running around 2kV from a BC-610 plate 
> transformer 
> and a pair of 866's.
> 
> --
> 73
> W5OMR
> 
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