----- Original Message -----
Sent: Friday, October 08, 2010 9:48
PM
Subject: LF: Re: Re: Decca 5501 500
Albert
I did not use any of the original PA components,
just the driver/PA unit.
I have the option of VFO or Xtal ctl to drive the
unit and I calculated the values for the PA coil and Caps. I
used an air wound coil and new caps, also a different ferrite
matching transformer to match PA fets to 50 ohms.
My HT supply is 60 Volts and the driver
voltage regulated 26Volts. One individuial unit is sufficient on 500 Kcs
but multiple units can be used with a suitable ratio of windings for
the matching transformer to 50 ohms or whatever Z you
require.
My antenna system and test equipment is
designed for 50 ohms. If you have optimum PA L/C values with
suitable ferrite 3C5 matching transformer then power output is similar to
the original design figures.
73 de mal/g3kev
----- Original Message -----
Sent: Friday, October 08, 2010 8:15
PM
Subject: LF: Re: Decca 5501 500
Hello Mal,
As you know I did the same a couple of years
ago. What is your max. output and at what supply voltage ?
Did you leave the coupling/output transformer as it was ?
73, Albert
PA0A
----- Original Message -----
Sent: Friday, October 08, 2010 8:52
PM
Subject: LF: Decca 5501 500
MF grp
I have modified a Decca 5501 unit for 500 Kcs
and am currently using it on the band and getting good
reports.
Circuit details available for anyone
interested in converting these units.
73 de mal/g3kev
