Greetings:
I see some discussion in the last few days about using microwave oven
transformers in power supplies for linear amplifiers. I have some small
experience along this line.
I recently acquired a new-to-me Jetta Diesel and I have been anxious to
return to CW mobile. During the winter in this area, when Jetta Diesels
have to be plugged into start, I tried an experiment, a well charged large
battery in the trunk and a 300W AC inverter, modern type, the plug into the
block heater, a way to start the car with a 15 minute run on the inverter
in cold weather. (Where I park the car I have no AC power available, I
live on a small island a mile off the mainland. You can also run a battery
charger off the inverter to charge the battery while travelling).
Looking at the inverter I decided to try and see if the inverter would run
an ex Microwave Oven transformer so that I might use a single 813 in the
trunk as the afterburner for a CW mobile station using a QRP rig as the
exciter. The transformer is loaded with a 275W dummy load of
resistors. The voltage rests at about 1650 V AC, dropping the resistive
load 90% takes it up to only 1750 V AC. I have run the setup for a number
of trips of 75 miles each way with about 50% duty cycle. The transformer
does not get excessively warm and the high voltage AC is reasonably stable.
Just my experience. I am currently trying to figure out how to regulate
10V and 3.5A for the 813 filament off of a 13V or higher battery voltage -
not much headroom....
The Microwave Oven that this came from was probably 15 years old, It was a
junker and I did not make any note of the parentage....
Larry
VA3LK
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