[Heathkit] SB-200 10M Power Output

[Glen Zook]

The tubes might be a little soft.  However, you are not going to get much over 450 watts output on 10 meters especially with that kind of drive.  Maybe 500 watts or a little more with brand new tubes and 100 watts drive.

Remember, the SB-200 was designed for around 100 watts drive and the efficiency drops off on 10 meters.

Glen, K9STH

Website:  http://k9sth.com


--- On Sun, 9/14/08, Mark K3MSB <mark.k3msb at gmail.com> wrote:

From: Mark K3MSB <mark.k3msb at gmail.com>

I'm getting between 550 and 600W out (CW) on 80-20, 500W on 15,  and
> between 300 and 400 on 10M. I'm trying to figure out if there's anything I can do to increase the output power on 10M.  Here's what I've measured:
 
28.0:   350-400W.   (75W drive, 1.5:1)
28.4:   300W          (75W drive, 1.5:1)
29.0:   300W          (50W drive, 2.1:1 )
 
For reference:
 
14.2:  600W  (60W, 1.2:1)
 
The figures in parenthesis are the drive from my 756P3 and the SWR indication between 756 and linear.
 
I initially thought to adjust L1 to bring down the SWR for a better tuned input match for the phone band.  However, after looking at what I'm getting on the low end of 10 (good SWR) and the mid and higher parts of 10M (mediorce SWR),  I don't think it's worth it to muck with L1 to get another 50 to 100W of output power.    I'm getting plenty of drive as it is.
 
The tubes are not new, and I've had to replace just about every resistor in the beastie.   I'm thinking the tubes are just soft.