Karl Matthias 馃嚭馃嚘
@relistan@mstdn.social  路  activity timestamp 2 weeks ago

This is my 2m band #HamRadio antenna amp I designed. It's quite different from my experiments a week ago. This one is a cascode layout with two BFR193s, a nearly perfect 50 ohm match on both sides across the whole band, and just shy of 18 dB of gain. Tuned with S-Params.

In theory! Now to build it and see how close I can get.

If you are looking at learning RF circuit design, take it from me: skip LTSpice and download Qucs-S. This is a really nice piece of software. #AmateurRadio
Karl Matthias 馃嚭馃嚘
@relistan@mstdn.social replied  路  activity timestamp 2 weeks ago
@n8dmt I can understand that. Yeah I soldered up a board with one of these to try things out. The 1206 size seems a good compromise for now for the resistors and capacitors. But these transistors are SOT323. Only 2mm on the long side. I managed it but no soldering awards will be won, for sure. We鈥檒l see how it goes when I try this circuit for real.
Karl Matthias 馃嚭馃嚘
@relistan@mstdn.social replied  路  activity timestamp 2 weeks ago
@gsuberland thank you! Hard work getting there 馃槄. Hopefully I can do the design justice with a soldering iron.

Good question re:MLCCs. I actually don鈥檛 know. There are many layers I鈥檝e just scratched the surface of. I picked it over regular Qucs because of the ngspice support. Anything you can do there it can do, too, but with nice UI.