As shown in A Previous Post, the QRP Labs QSX is on its way. It’s a SDR based all mode HF rig, 80m through 10m. It’ll be digital ready, too which is very cool! Recently we looked at what it’s going to take to build the QSX, and in this post we’re going to actually start building a component of the QSX: the QSX PA.
The 10W HF PA that’s going to be used in the QSX is up for sale now and I couldn’t resist ordering one up and getting a taste of the QSX goodness to come. I’m going to cut straight to the chase: Go slow, and identify ALL parts before installing them. One mistake I made was to put the 78L05 in place of a BS170. This meant I had to completely de-solder it and do it again.
I used a trick that I’ve developed through many screw ups over the years: Huge solder blobs that stay molten so you can pull the component out. Then warm it up again and knock the solder blob off with a firm tap. It’s ugly but it works. Another secret weapon for building these small electronics is something you can probably raid from the bathroom: tweezers! They’re invaluable when dealing with fine wires and small components.
The actual build though? Not bad. I used my normal set of tools which is basically all the stuff listed on my post “Low Budget Tools and Parts for the Budget Builder“. The 10W HF PA manual is excellent, and it walks you through every step. Assembly starts where most QRP Labs kits start: Inductors and transformers. There are 5 total, and the instructions are crystal clear. To make the bifilar wires, I like to tape one end of the wire (already folded in half) to a pencil, and just hold the other side, and then start twisting the pencil. Once the inductors and transformers are done you’ll move on to the larger components. Things get progressively smaller until it’s time to install all the MOSFETs.
One thing I love about QRP Labs kits is that everything you need is included with the kit. You don’t need to raid your junk box or make another order to finish it off. You can order a QRP Labs 10W HF PA Here. Check out the pictures and let us know what you think below!
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