Re: QDX - protection of BS17O PA
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Hello Rob
The buck converter topic is I believe, related to QMX and is a different subject. Here we are talking about the QDX finals, SWR protection. Quite possibly everything got mixed, I am not sure.?
It would be interesting to know more about the nature of that certain impedance where oscillation occurs and what kind of oscillation.?
Hans,?
I found on the QDX 12 V version a point where, on 40M and a certain impedance of the antenna load the QDX started to oscilate at transmitting. Current went up at oscilating from the normal arround 800mA to more than 1,2A. Thats why I am using a good buck converter where I limit the current to max. 950mA and 11,8V. The antenna tuner is a bridge QRP type, switching off the bridge after tuning.
Never fried a BS170 until now. No other prptection.
Aboit the buck converter ther was already a topic in this group.
Perhaps the oscilation is the real problem.
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