Re: LF: PA working again. No more QRP for now

[VIGILANT Luis Fernández <luis@vigilant.es>]

Hi Stefan, MF

Not really :-)
I use a couple of relais to bypass the PA and make QRP tests. Thrystor cuts this relais to bypass mode

So PA and power supply keep on but without driving. After power off then on the protecting circuit gets reset and PA go online again

Fuse is grown up enought to protect by itself. Seems to be a fuse rule ;-)

73 de Luis
EA5DOM

Hi Luis,

The thyristor will bypass the PA for the rest of the night then? Is it in front of or behind the fuse? :-)
Some power supplies may not like the idea. Or do you use a car battery in parallel?

73, Stefan

Am 24.03.2016 12:01, schrieb VIGILANT Luis Fernández:

Hi MF

PA is fixed now and current protection added. Running nominal 5A@12V at the moment

Getting WSPR spots from DL in daylight

The mosfet was intact ! That explained why it was not showing short circuit

It was the drain copper track in the PCB that finally burned out preserving and protecting the fuse

Not a spot event, but the consequence of many hours running with some antenna mismatch

and currents over 15A may be. An LM311 and thristor sensing the voltage from across the Amp meter

will trigger with this current values and bypass the PA for the rest of the night, if that happens again

PS: Upss! forgot to set my WSPR message for 1W ERP

73 de Luis

EA5DOM