[Collins] Re: My first technical question

Dr. Gerald N. Johnson, electrical engineer [email protected]
Sat, 29 Jun 2002 09:46:09 -0500


Wn4i wrote:
> 
> Welcome Jerry ......In  SSB are you in favor  of using  a somewhat  higher
> Plate voltage ( 900-1000 volts using solid state 5R4 )  to protect the
> screens from secondary emissions .....and have a good 120 watts output as
> well ?
> 
> Same question  for the 30L-1  ...are you in favor of using BIGGER  voltage
> doubler capacitors ... like I do ...to improve the dynamic regulation  for
> every peaks of my modulation .....800 watts peaks easy with no problems
> since 1997 ?...Dxing every day .
> 
> Be free to answer to the full Collins list if you like ......mentioning my
> name or not .
> 
> Best Regards
> 
> Yves  Wn4i .
> 
> Yves Pautard
> 5833 Dryden rd.
> West Palm Beach
> Florida 33415.....561-689-8819


Yves, I don't object to the higher plate voltage, thus lower heat
dissipation in the power supply, but I do not favor higher RF output.
The loading capacitors and tubes are marginal, and the limited load
range of the S-Line /KWM2 Pi network can stretch them further. I prefer
to run 6146B at 6146 ratings for super longevity of the tubes and better
longevity of the loading capacitors. the 20% power difference is less
than a dB and can't be detected at any distant location, propagation
changes several times that amount each minute.

Larger power supply capacitors nearly always lead to better dynamic
regulation, though one should be certain the larger capacitors, and the
rectifiers, are capable of the increased peak currents from
rectification and supplying the load peaks. Greater capacitance in the
same package, does not necessarily increase the ripple current rating of
the electrolytic capacitor. In the case of the 30L1, rectification peak
currents are pretty much limited by the transformer windings so changing
the capacitors won't increase the peaks significantly.

73, Jerry, K0CQ
-- 
Entire content copyright Dr. Gerald N. Johnson. Reproduction by
permission only.