Your measurments of output power are wrong somewere.
>
> From: Mike Selfridge <scifiguy@starband.net>
> Date: 2003/12/06 Sat PM 05:37:46 EST
> To: amps@contesting.com
> Subject: [Amps] SB-200 Output Power Too High?
>
> I have a very well kept Heathkit SB-200 I purchased a couple months
> ago. It has the Harbach power supply, soft start, and soft key mods. I am
> running it on 240VAC (measures 232VAC when keydown). The tubes are new
> (about 20 hours) Taylor 572Bs.
>
> Before buying the amp, I had read that the SB-200 can output about 500W to
> 700W CW, with 100W input. However, much to my surprise and delight, this
> amp puts out a lot more.
>
> The highest output seems to be on 20 meters, where it actually achieves
> 1100W CW into a dummy load (found this out by accident, when I drove it
> with 100W, then noticed the plate current was way too high, so very quickly
> reduced the drive). At 70W input, the plate current reads 500mA, and the
> output is about 900W CW. 40 and 80 meters also produce similar power, but
> with full 100W drive.
>
> Now, before I hear that my power meter must be bad or out of calibration,
> let me say that the meter is new, and reads the same as my backup meter, as
> well as reading exactly what it should with my FT-897 (reads the same as
> the test data on the calibration sheet from Yaesu, within a couple percent).
>
> I checked the output on all bands, using a spectrum analyzer, and found
> nothing unusual, so I know it is not producing parasitic oscillations, nor
> is the harmonic content too high. On the air, I have had nothing but
> positive reports.
>
> I know you can't get something for nothing, and class B amplifiers don't
> operate at 93% efficiency (yup, that's what I calculated), so I assume the
> meter on the front of the amplifier must be inaccurate. I suspect the
> plate current and/or high voltage is higher than the meter shows, so I'll
> have to calibrate it with a current source, and replace the appropriate
> components to give an accurate reading.
>
> Has anyone else with an SB-200 seen output this high? My web searches show
> that most get about 600W CW. I don't push the output to the limit on CW
> operation, but I love the ability to get 1100W PEP on SSB!
>
> 73
>
> --Mike (N6QG)
>
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