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Schematic Of 200 watt amp:
There are
some schematic of the 200 watt amplifier. The first is the
original schematic of the amp when built in 1968. You should
be able to fine this in the ARRL Hand Books from 1968 - 1972.
If not you can download the PDF file from this page. You will
see things circle in orange these are all the change's I made
to this
project. First all input networks were no longer needed has
this was going to be a mono band amplifier. You can still add
a input circuit what ever band you want to build this amp even
if it is a mono band amp. But being my radio has a built in
antenna tuner, it's used to tune the input of the amplifier.
Second came the Pi Network. I used the loading coil from my
junk SB-200 amplifier and at the same time decide to add in 40
meters as well. I used another relay to switch between the
coil taps to switch between the 30 and 40 meter band, which
also has a led lamp to let me know the amp is in the 40 meter
position. There's a switch on the front panel to do the band
switching.
Third came the metering. I decide that I wanted three meters
to monitor the amplifier. Meters were added for the plate
current, grid current and high voltage.
In my drawing of this schematic you will be able to see how I
added in the metering. Funny thing, I was able to fine the
original plate choke used in this circuit off
ebay. I though I would not be able to locate one.
Parts for this project can be found on the original amplifier
parts list.
Here's a PDF file of the original 200 watt 811A amplifier. Click here --
->
Here's
a PDF file of my schematic. The 200 watt 811A 30/40 meter amplifier.
Click here -->
If you
build this amp I hope you have fun doing so. And most of
all be carefully your dealing with high voltage that can KILL
YOU!!! no joke. |
