Sunday, November 3, 2013
I've really been enjoying using my BITX17 without an enclosure. Having all the electronics exposed on the workbench really accentuated the homebrew nature of this rig. But obviously it was time to box this thing up. At a local craft store, I found a wooden box that is exactly the right size for my BITX copper clad board. I put the BITX in the box yesterday. I kind of miss the exposed electronics.
The far left control is AF gain. The need for a few inches of wire to the pot has introduced a bit of AC hum. I'll try to knock this down with better shielding on the lead to the pot.
But this gets brings us too a bigger question: the need for a cabinet that shields. Obviously the wood shields it only from dust. I know there are some benefits to putting this thing in a proper metal box. The AC hum would be less of a problem. Also -- listen to this -- in the morning, before 17 opens, I can hear -- faintly -- the WWV transmission on 5 MHz (recall that the IF in this rig is 5 MHz). And if I ever build an external linear amp for this rig (I might), I guess a proper metal box would help prevent the kind of oscillation that often drives me crazy on these kinds of projects.
So, what do you guys think? Stick with the wood, or put it in a metal box? Any thoughts on putting metal shielding material around the inside of the box (thick aluminum of tin foil)?
(The other black control knob is for a rotary switch that will allow me to select among two or three crystals for the VXO. )
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