Thx Adrian, Hans and Allison.
Appreciate the feedback.
Will proceed carefully.
Greg
On Thu, Mar 14, 2024 at 9:49 AM, Adrian YO3GFH via groups.io
<p_adr@...> wrote:
Hi Greg,
AFAIK, IRF510 was designed to be a power switching device. Many years ago, some kind soul found that it can also be used as a low cost HF power amp, with more than decent results. But, as there's no free lunch in this universe, so is the case with IRF510 - due to it's internal capacities, it works best in the low bands and kinda so-so under 20m.
Incidentally, my first amp that didn't oscillate and actually worked was a IRF510 design for 80 and 40 meter, published by a DL ham. It was 25 years ago, I think I still have it somewhere under the bed :-)?
Using some sort of resistive attenuator is probably a good idea, if you can't power the QMX from something lower than 12V. While tinkering with atten. and bias, it would be nice to have a scope to make sure that you actually output a sine.
Regards,
YO3GFH
op. Adrian
