Hello LF group,
After a break of 2 days on LF, which is VERY long for me, i am back on
about 136.172. I've done various changes on the circuit and even use
another VFO (the DDS is used in the first VLF experiments). It is
running on batteries and i just opened the windows to the shack so
there may be a little drift.
I'm back with -3 dB f.s. and its frozen outside! :-)
This is the last pair (4 pcs.) of FETs and i will go back to the
IRFP460 then. However i found there is also a IRFP460A
which looks a bit more suitable for such critical switch mode
applications. I've already ordered 20 pcs of them ;-) The FETs i'm
using right now have rise and fall times below 10 ns which may be even
worse in this application. But maybe the actual reason why they blow up
is a completely different. Thus i will test the DDS now (no phase
glitches)...
If someone wants to report about the signal, it is welcome :-)
73, Stefan/DK7FC
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