Re: BITX 14MHz Build #bitx20


Hi Aaron,

I not used MeSquares, but have done quite a bit of "dead bug" construction (which is just placing parts - upside down or not - over an unetched PCB).  Basically I just follow the schematic as it pretty much already organizes the parts in the place you want them on the board.  Start with the receiver antenna connector (or short piece of coax or twisted line) and just start building out.  The receive bandpass filter is first, then the RF amp, mixer, etc all follow.  The build will probably end up long an narrow, but that is good as it keeps the higher level signals away from the lower level ones.  Reading the description of Farhan's build you will see he did it this way too.  You might want to build the VFO, BFO, and AF amp on separate PCB's.  This will allow you to shield the RF one's and also allow you to keep the build from getting too long.  For sure I would put the PA on a separate board.

When soldering parts to the ground plane, remember that is one big piece of copper that you are heating up.  It will take higher heat and a longer heating time than the parts.  Clean then wet the tip of the iron with fresh solder, place the tip on the board where you want to solder, and wait until solder placed on the PCB near the tip will melt by itself.  Then you can place the part to be soldered to it onto the board.  This will keep the part from over heating.

You can place parts upside down or rightside up -- whatever is easiest and makes connections the simplest.



PS:  Ferrite core toroids or old TV baluns will work much better than tap washers for transformers and inductors as the designer found out in the end.

PSS: If you can't find Toko type transformers for the bandpass filter, you can use fixed inductors and accomplish the filter adjustment by making the capacitors variable instead (trimmer caps). 

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