> >Having an issue with a homemade GS35B operationon 15 and 17 m. When
> >keyed, the power seems to hesitate before going up to 1.5 KW
> >output. CW is a mess on these bands due to this situation. On RTTY
> >the power hesitation is so short that it doesn't present a
> >problem. Amp. seems to be okay to about 1200 W, but the hesitation
> >returns above this level. Other bands, 10, 20, 40, 80, 160 work okay.
> >
> >Using a TIP147 transistor in a bias circuit similar to Ian's Triode
> >Board bias circuit. Cut-off bias is provided by a 10 KOhm resistor.
> >
> >The filament choke is ~25 bifilar turns of #16 on a 10"X1"X1/4"
> >oblong ferrite rod. An additional choke of 20 turns #20 on a ferrite
> >rod, 3.5" long and 3/8" dia., is in the line from the filament
> >secondary center tap to the bias circuit.
> >
> >This a strange situation as seen on 17 and 15 meters using either an
> >antenna or a dummy load. On the other bands, the power smoothly
> >rises to full output.
> >
> >Any ideas on how to fix this situation are appreciated.
Put an SWR bridge or wattmeter between the exciter and the amp. This will
tell you if the power is coming up slow out of the exciter, and what the
input vswr is on the affected bands. This will tell you if the problem is in
the amp or the exciter. Report your findings. We will need a schematic to
see how you have things lashed up, and what component values you are using,
if the problem is in the amp.
(((73)))
Phil Clements,
K5PC
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