SB-200

[Peter A Markavage]

It's a linear amplifier. There's really no need to dip the dipper and
peak the peaker on a SB-200. Adjust your 820 for "normal operation" (dip,
load, drive, ALC, etc.) preferably into a dummy load, put the SB-200 in
line, key both, grab both the tune and load controls and adjust for
maximum RF output. Minor touching up of the 820 plate and load controls
might be necessary if the 820 is not looking at approx. 50 ohms input
impedance of the SB-200 (which it won't). This has been my procedure with
my SB-200 since 1969 and still using the same 572B's. Also, been running
my SB-200 on AM since 1985 using the same procedure. In this mode, the
driver is either an Icom 756 PRO II, a pair of Kenwood 599D Twins, or a
Johnson Ranger running in low power.

Pete, wa2cwa

On Sat, 19 Feb 2005 20:02:20 -0500 Walt w3fnz <wsmk at PTD.NET> writes:
> Thanks Bill, Tom and Bob,
> 
> Well, I got the SB-200 up and running!   After all the investigating 
> and going around in circles, I did it.  I'm almost reluctant to say. 
>  It was only after Tom's statement about dipping the plate to get 
> the tank ckt in resonance. Wait a minute;  I knew that!  After all, 
> I tune up the 520 and the 820 all the time with no problems.   When 
> following the tune up procedure in the manual there was nothing 
> mentioned about dipping the plate current. I never zeroed in on the 
> starting point.  As soon as I began to increase the drive I dipped 
> the plate, increased the drive and adjusted the tune and load, just 
> like I do with kenwoods. Whalla!!  The SB-200 came alive.  I've got 
> 375ma on the plate with less than 50ma on the grid putting out about 
> 500w  with only 65w coming from the 820.  And I have plenty of room 
> to go more!   I can't believe I didn't realize it from the 
> beginning.  I just got so in to the manual word for word that it 
> never dawned on me. 
> If it weren't for your help I probably would still be investigating. 
>  Thanks guys, This is one I won't forget!
> Walt, w3fnz

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