[QRO] Fwd: GS35B Strange Output

[Mike]

>Date: Sun, 02 Jul 2006 23:48:17 -0400
>To: QRO Reflector
>From: Mike <k4gmh at arrl.net>
>Subject: GS35B Strange Output
>
>Hello,
>
>Having an issue with a homemade GS35B operation on 15 and 17 
>m.  When keyed, the power seems to hesitate slightly 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 on these bands.  Other bands, 
>10, 20, 40, 80, 160 the amp works 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
>
>         73,
>         Mike, K4GMH