I have been having massive problems with the RF design I have using the RD100HHF1 MOSFET. I thought it would be easily accomplished like using the IRF510 but I have had troubles with the RF Input since day one. So much so that I am contemplating a change in direction.
On the HF SuperPacker1 and HF SuperPacker2, I used a design based on the Communication Concept Inc (Communication-concepts.com) AN762 (140W version). From this basic circuit board, I created our version which included all the support circuits, etc. See: http://site.hfprojectsyahoo.com/hf_superpacker_pro_ver_2 for details.
Now I more convinced I need to follow my past foot steps of development and start with the CCI AN758 Amplifier as the basis for this new amp. The AN758 is not a production design but is an engineering starting point as with other CCI products.
The AN758 HF amplifier is a push-pull linear amplifier designed for 300 watts of PEP or CW output power across the 2 to 30 MHz frequency band. The high power MRF429 RF transistors are used in this amplifier design. The AN758 operates from a 50 Vdc power supply. I would like to back off on the implementation to a more conservative 100–150W and integrally include the DC/DC Converter. I like the stand-alone module idea because multiple modules including our 100W LPF Modules could be combined for higher power output in your own spin-off QRO design
. If you modularize the amp and LPF as a unit, you would not exceed the 100W LPF rating. The AN758 application note you will see the need for a driver amp. I intend to include the driver in the amp module design so this can be driven from QRP such as the FT817, etc. AN758 information: http://www.communication-concepts.com/index.php/amplifiers/an758/an758.html
I recall going through about 5 versions before getting a satisfactory layout for the HF SuperPacker Pro V2. I learned a great deal from that experience that I can directly apply to the adaptation of the AN758 design.
We are not continuing the HF SuperPackerPro V2 Amp because it used an internal heat sink and fan combination. I want the new design to more environmentally sealed with the heat sinks on the skin of the case. We also used a Motorola high gain transistor that is no longer available.
I would be happy to hear your comments before making a decision on a new direction. I think it has the potential to be a great group-build project like the predecessors.
73, K5OOR – Virgil