Last time I left-off having built a second version of the pre-amp proper using the designers suggested layout and the circuit worked much better (as measured by the steady-state current). Now onto the rest of the pre-amp box.
Again, taking cues from the original design, I decided to include attenuators, both before and after the amplifier. To do this, I used one of many calculators online to calculate the resistors for a T-style attenuator. The resistors were ordered as a part of the original pre-amp parts order. Metal film, 1%, still pennies a piece. I also decided to include an antenna switch in the design.
When it came to construction, wary of my previous inattentiveness to layout, I wanted to do the best I could to keep the leads short and provide a solid ground plane, even just for the attenuators. I decided to use a strip of PCB scrap as the common ground throughout the signal path. I also decided, in what is likely an abundance of caution, to use RG-316 coax between the attenuators.
The attenuators would be switched, and I used the leads of the switch as mounting points for the resistors. The switches were DPDT, bypassing the attenuator in one position and routing through it in another. Only the signal side of the attenuator was switched, the ground side was directly connected to the PCB strip.
Using an existing enclosure needing to finally have a project to house, I prepped the front plate for mounting the switches, punching guide holes for all the switches and drilling them out with a hand drill. The results were not the prettiest but most of the failings in my handiwork are hidden by the switches mounting hardware.
Here are the results as seen from the inside of the enclosure.
The back side of the enclosure was used to mount the three input antenna jacks, the output jack, and the power jack. This was all much simpler; just drilling holes and mounting the hardware; the coax connections come later.
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