DXCC 100 Finally!!!!!!!

Its taken me just under 5 years to make DXCC 100. Most of these contacts were made low power. Fcall in VK is 10w and I worked about 80 of these on that license. The next 20 took a license upgrade and 20m, FT8, 30w and 9 months to make. Yeah, anyone who says you can make DXCC in a weekend using FT8 is deluded. I worked 67 confirmed in 9 months, not 100 in a weekend. HAHA. Anyway I am pleased to have finally got DXCC 100. WOOO Me.

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A Tiny Skateboard

Yesterday my grandson Lucus who is 3 came wandering into my lab while i was working on the pcb design for the rf amp. Being a family man I drop everything and we had the following conversation.

Lucus: What game are you playing Grandad?
Me: Its not a game, i am laying out a pcb board.
Lucus: What’s that? (looks confused)
Me: I hand him the pcb pictured above and say, see all these tiny holes (vias) I am placing them on a new board that i want to have made.
Lucus: Arhhh ok you are making a tiny skateboard. He then proceeds to tell me all about the the things he got for his birthday and how none of them were a skateboard.

HAHAHAHA. Kids are awesome.

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100w? + Amp Part 2

Schematic: vk4hat_amp

Ok I have made wholesale changes to the schematic. Changed the voltage divider biasing to a more conventional biasing schema, adding in some feedback, which i am a bit unsure of, its probably not totally necessary for 40 and 20m band amplifiers, but for higher using IRF510’s its needed, I can always not populate those footprints when i build it. The resistors i had from source to ground were removed, those were meant to be swamp resistors on the gate to tame the lower bands, but they are probably not really needed and finally the biggest change has been to the output transformer, in which the single turn winding is going to be copper tubes with VCC to the drains delivered via the center tap on the single turn winding.

I have also been thinking about ground paths and return loops and all that other stuff that is over my head. But, I think something i am going to do is change the SMD bias components to through hole and move the bias traces to the top of the board, this will give me an almost unbroken ground on the bottom layer. Which can only been a good thing I guess. And I also need to do some research on the rf power handling of trace widths. Yet another thing i really don’t have much of a clue about. So i need to unroute the whole board almost and kind of start again. But for now, its off to find some credible source on trace widths and rf power levels.

 

Lots has changed since i posted this, this morning. Pretty much changed everything in the board layout. Here is a 3d render of where its at. Yes, i changed back to through hole parts because it would allow me to jump a trace using resistors and keep the bottom copper layer almost completely unbroken. So its a perfect ground plane to stick the broken top copper to.

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