Atilla, Thanks you have read what I have written and further your experience aligns with mine for hacking these chips at least into the GHz range. I suspect it really falls apart in the 2-3 GHz and above region. But I have built a lot in the 1.296 GHz region so have that experience at least. Regards Paul WB8TSL
On Thu, Dec 3, 2015 at 5:34 AM, Attila Kinali <[email protected]> wrote: > Salut, > > On Wed, 2 Dec 2015 18:39:55 -0500 > paul swed <[email protected]> wrote: > > > Just adding that this is home brew so no real boards. At the IF level > thats > > both large enough and easy enough to add to a ground plane. So its > > reasonable to build the basics and add stuff as needed. > > The LNA front end is cheap so will get that just to try. Have to look at > > the hot air suggested above to see what that might cost. > > The Leister one costs IIRC 300-400EUR. I.e. not the thing you'd buy > for a single project. There might be cheaper ones though. All you > need is something that is small enough that you can confortably > fit into your hand, has a small nozzle and temperature control between > 200°C and >400°C. > > But if you are not building a board anyways, there is an even "simpler" > way to go: Dead-Bug! :-) > For 0.5mm QFN/DFN i usually use AWG30 wirewrap wire or 0.08mm^2 tinned > copper wire. Enamelled wire should work too, but I am generally to lazy to > tin the tips and make sure that no blobs of enamel residue were left on > the wire. The way to ensure that you dont get any shorts is to spread the > wires out, such they gain enough distance. As you will be soldering RF > chips, > which have a ground pad in the center that needs to be soldered, i > recommend > using solder wick. Use 2 wide strips and solder them first (before any of > the pads) onto the ground pad, such that they point to opposide directions. > Make sure you do get solder on more of the wick than necessary. After > you have finished all the pads, solder the wicks to your groundplane at an > as short distance as possible. > > This is of course not optimal, but the inductance of the wick should be > small enough, thanks to the width and the braiding. And you have the > advantage > that you can rework if something doesn't work out. > > As for equpiment, you will need a soldering iron with an as fine tip as > possible > (0.5mm is absolute maximum, 0.3mm is what you should get, if you can get a > smaller one, take that one). 0.3mm solder (use leaded, it's easier to work > with). > I do not recommend using thinner solder. With those the core gets so tin > that > you dont get enough flux. Oh.. and be carefull about stretching the solder > wire. > The metal part can be stretched quite easily with such thin wires, but the > core > doesn't. So if you get this speckled look, cut of that part with some fine > side cutting pliers. You will also need at least some kind of optics with > an > magnification in the range of 10 to 20 to check the solder joints. It would > be best if you had access to a stereo microscope (with an 10-20 > magnification) > but if you have good eyes you can do without and instead using some > magnifing > glass (i recommend line tester/weaver's glass) to see whether the joint is > ok and doesn't have any shorts. > > HTH > > Attila Kinali > -- > It is upon moral qualities that a society is ultimately founded. All > the prosperity and technological sophistication in the world is of no > use without that foundation. > -- Miss Matheson, The Diamond Age, Neil Stephenson > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
