Category: Blog
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What is a Class F amplifier and why does it matter?
The short answer is efficiency. A true linear amplifier is limited in its efficiency. A realistic number is 60%, meaning if your output is 300 watts, you’ve got 200 watts of heat to get rid of. A class F amplifier is NOT a linear amplifier. The transistor is driven with closer to a square wave…
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My Amplifier Works!
The tests yesterday went well enough that I was comfortable getting on the air. So far the GaN FET is holding strong! I think the tweaks to the circuits improved efficiency (around 90% PAE I think) and removed the risk of a 200 amp current surge as it turned off. The Class F portion of…
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Class H & F Amplifier Progress
The surface mount parts are on! I still need to do all the through hole parts, and then test the darn thing… more updates later today. Update 1: Through hole parts are on, mechanicals look good. Need to add heat pipes from the FETs still, but the fan is nice and quiet (which was the…
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My meander Yagi turned into a meander Moxon
As expected, the antenna did not perform as modeled on my balcony. I think my F/B ratio is not great, but I seem to have a strong beam towards CA / NM / AZ. Once I mount it above the railing, I should be able to turn it , but I’m guessing South will always…
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Meander Yagi V2
I took some measurements of my balcony, and modified my EZNEC file, adding some straight sections at the end. The goal is to make it easy to disassemble and tune, so I bought 4 cheap telescoping sections (max length 74 cm) from Amazon (4 pack for $12). EZNEC says the reflector should only be 4…
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Learning EZNEC – My Meander Yagi
Years ago, (probably the late ’90s) I played with EZNEC and haven’t really used it much… until today. I was trying to find information on reduced size yagis using meander techniques. There really wasn’t much out there, so I tried my own. Ignore the W8JK name – I guess I forgot to update the comments…