I should have tried this a long time ago. It works great. The power supply that I picked up at the Kempton Park rally many years ago happens to have a 25 volt unregulated output. Coincidence you say? I think not. TRGHS.
Farhan provides a really excellent description of how to do this:
http://hfsignals.blogspot.com/p/25-watt-linear-for-40-and-20.html
You can do everything with IRF, when You use more than 20V 😉 Just 8V difference – and you can not recognize Your device…
Back in the 90s, used the 510 to get 10W @ 30Mhz on 13.8 volts. Never used it on the air or much beyond playing on a sheet of copper clad mounted to a heatsink. Just saw it in a box a couple of weeks ago. Built it from an article from 73 magazine, November 1990 is what is in my notes. N9XYP
I have a bunch of boost converters here that are doing nothing and are rated higher than the needs of the Bitx 40, I have been thinking of putting one into the box and bringing the power upto 10W out, SSB QRP levels, not a massive increase, but enough to increase my chances of success when out portable. Rob.
Did anybody test something like that as a PS for PA? Looks cheap and interesting. http://www.ebay.com/itm/150W-DC-DC-Boost-Converter-10-32V-to-12-35V-6A-Step-Up-Power-supply-module-/141316770525